Author Topic: Overheard at Work  (Read 6415118 times)

Imustacheyouaquestion

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Re: Overheard at Work
« Reply #18500 on: August 30, 2017, 09:47:26 AM »
Carpooled with a few co-workers to lunch last week (there were 6 of us) and one woman suddenly realized her Ford Explorer had six seats and offered to drive. She didn't know how to access the back row of seats because she had never used it. Single lady with a small dog driving a giant SUV with a third row that she had so little use for that she's literally never had anyone seated there.

RidetheRain

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Re: Overheard at Work
« Reply #18501 on: August 30, 2017, 09:54:44 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.
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RWD

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Re: Overheard at Work
« Reply #18502 on: August 30, 2017, 10:15:38 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

Agreed. Even in non-ridiculous areas it's probably good practice to set a maximum reasonable temperature than to turn it off entirely.

The point though is that if it's more efficient to turn it off entirely then it's also going to be more efficient to raise the temperature threshold while you're out rather than leave it flat.

cheapass

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Re: Overheard at Work
« Reply #18503 on: August 30, 2017, 10:24:19 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

Agreed. Even in non-ridiculous areas it's probably good practice to set a maximum reasonable temperature than to turn it off entirely.

The point though is that if it's more efficient to turn it off entirely then it's also going to be more efficient to raise the temperature threshold while you're out rather than leave it flat.

Good point. There is an optimum temperature threshold, just gotta find it.
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bender

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Re: Overheard at Work
« Reply #18504 on: August 30, 2017, 10:57:54 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

Agreed. Even in non-ridiculous areas it's probably good practice to set a maximum reasonable temperature than to turn it off entirely.

The point though is that if it's more efficient to turn it off entirely then it's also going to be more efficient to raise the temperature threshold while you're out rather than leave it flat.

Good point. There is an optimum temperature threshold, just gotta find it.

What kind of temps are we talking?  90+?  Is the fridge in direct sunlight?  The argument that it takes less electricity to keep an entire home cooler does not make sense unless you're leaving the fridge door open.  I think it may be time for a new fridge.

Also the argument about keeping maintaining a consistent indoor air temp all summer is a myth.  It's much better to only run it when you're at home.  Modern AC units can efficiently cooling a place down very quickly.


RidetheRain

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Re: Overheard at Work
« Reply #18505 on: August 30, 2017, 11:06:47 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

Agreed. Even in non-ridiculous areas it's probably good practice to set a maximum reasonable temperature than to turn it off entirely.

The point though is that if it's more efficient to turn it off entirely then it's also going to be more efficient to raise the temperature threshold while you're out rather than leave it flat.

Good point. There is an optimum temperature threshold, just gotta find it.

What kind of temps are we talking?  90+?  Is the fridge in direct sunlight?  The argument that it takes less electricity to keep an entire home cooler does not make sense unless you're leaving the fridge door open.  I think it may be time for a new fridge.

Also the argument about keeping maintaining a consistent indoor air temp all summer is a myth.  It's much better to only run it when you're at home.  Modern AC units can efficiently cooling a place down very quickly.

I admit, mine was an extreme case, but the point stands I think. I was living in a really, really crappy apartment where the only a/c was a wall unit about 8 feet away from the fridge. Downstairs temps averaged the mid-80s w/ a/c. Upstairs temps were typically 90-100 range (no a/c). It's amazing what you'll live with when you teeter on the poverty line. I have since moved.

But, that's extreme. In the real world, central air is at maximum efficiency when working on high. But central air also turns on and off as required so depending on your location, home insulation, and energy costs your results may vary.
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M5

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Re: Overheard at Work
« Reply #18506 on: August 30, 2017, 11:22:37 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

Agreed. Even in non-ridiculous areas it's probably good practice to set a maximum reasonable temperature than to turn it off entirely.

The point though is that if it's more efficient to turn it off entirely then it's also going to be more efficient to raise the temperature threshold while you're out rather than leave it flat.

Good point. There is an optimum temperature threshold, just gotta find it.

What kind of temps are we talking?  90+?  Is the fridge in direct sunlight?  The argument that it takes less electricity to keep an entire home cooler does not make sense unless you're leaving the fridge door open.  I think it may be time for a new fridge.

Also the argument about keeping maintaining a consistent indoor air temp all summer is a myth.  It's much better to only run it when you're at home.  Modern AC units can efficiently cooling a place down very quickly.

HA! I've had the exact same argument with people I work with. As long as your house is pretty well insulated, you should have no problem leaving your a/c or heat off while you aren't home (unless you will be gone for several days). I have found that even in 100 degree weather my house never climbs above 80. When I get home, I turn the a/c on for a couple hours and it's cool enough to last another 24hrs before repeating. Of course, if the outside temperature will be cool enough overnight, I open windows and let mother nature do the work for me.

Just for kicks, I left my a/c set at 72 for a couple days.. energy cost was more than double for those days!

frugalnacho

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Re: Overheard at Work
« Reply #18507 on: August 30, 2017, 11:33:03 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

No fucking way this is true.  It doesn't even make sense.  You just had a malfunctioning fridge that couldn't keep cold enough, or the efficiency difference between your fridge and AC unit was so disparate that no one should have been using that fridge (ie it was clearly malfunctioning). 

I also call bullshit on anyone saying it takes 3 days to recool their house or anything else.  It takes less energy to turn the AC or heater off/down while you are away and only run it while you are home, absolutely no exceptions.   You can make the argument that you are more comfortable for some short period by keeping a constant temperature rather than turning the unit off then back on and waiting for it to reach your ideal temperature, but leaving it on uses more total energy absolutely no exceptions ever.  That's just the laws of thermodynamics. 

Prairie Stash

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Re: Overheard at Work
« Reply #18508 on: August 30, 2017, 11:58:16 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

No fucking way this is true.  It doesn't even make sense.  You just had a malfunctioning fridge that couldn't keep cold enough, or the efficiency difference between your fridge and AC unit was so disparate that no one should have been using that fridge (ie it was clearly malfunctioning). 

I also call bullshit on anyone saying it takes 3 days to recool their house or anything else.  It takes less energy to turn the AC or heater off/down while you are away and only run it while you are home, absolutely no exceptions.   You can make the argument that you are more comfortable for some short period by keeping a constant temperature rather than turning the unit off then back on and waiting for it to reach your ideal temperature, but leaving it on uses more total energy absolutely no exceptions ever.  That's just the laws of thermodynamics.
It could be true if it was severely malfunctioning. In that case the solution should have been a fridge replacement but the AC was used instead. Possibly the coils were severely dust laden, a good cleaning would fix it, that's my guess for poor heat transfer. Maybe the guy had empirical evidence, but holy CRAP! What kind of electric bills would show much difference? Is the guy saying he can notice changes in his bill, which is lower, when the AC is on? HOLY Heatwave Batman, how large are the electric bills when AC causes them to appear smaller? This requires more electricity to be used in running the pump then in the actual heat transfer, its ridiculous.

Although extremely silly, never underestimate the ability of people to need a face punch. Instead of fixing problems, like dirty coils that need a good vacuum or replacement, some people will turn up the AC to have their whole house operate as a fridge.

OP - Clean your fridge coils. If that doesn't work, get a new fridge, yours is broken.

zolotiyeruki

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Re: Overheard at Work
« Reply #18509 on: August 30, 2017, 11:57:39 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.
If it helps, you can think about A/C as a heat-removal machine.  The more heat it removes from your home, the higher your bill.  The other side of the equation is things that put heat into your home.  Appliances, computers, stoves, outside air, and of course, the sun.  Let's ignore the man-made stuff and the sun, and focus on the outside air.  The amount of heat that enters your home through the walls is proportional to the temperature difference between inside and outside.  Roughly speaking, you get twice as much energy entering your 75-degree home if it's 95 degrees outside (20 degree difference) vs 85 (10 degree difference).

Let's do a case studey: For simplicity's sake, let's say that during the 10 hours you're away from home for work, the average temperature outside is 85 degrees, and your thermostat is set at 75.  We'll compare two houses one where the A/C is left on during the day, and one where the A/C is turned off when you leave and turned on when you return.  Let's say that the houses are insulated so that when it's 10 degrees warmer outside, enough energy enters the home to increase interior temperatures by 1 degree per hour.  We'll call that amount of energy X btu/hour.  Whatever the total energy input into the houses over the 10 hours must be removed by the A/C.

For the A/C-always-on house, the calculation is simple: 10 hours * X btu/hour.

For the A/C-off-during-the-day house, the calculation is a bit more complex and probably involves calculus.  Roughly speaking, during the first hour, the house gains X btu, which causes the temperature to rise by 1 degree.  During the second hour, however, the temperature difference is only 9 degrees, so the energy gained is only 0.9X btus.  During the third hour, the delta-T is 8.1 degrees, so 8.1X btus are added, and so on.  By the end of the day, the temperature has risen 4.5 degrees, and the total energy gained is only about 6.5 * X btus. 

Now, this ignores other heat sources (sun, appliances, etc), but it's not a big deal--as they heat up the house faster, the delta T between inside and outside shrinks, and the house will gain less energy from the outside air.

It's also worth pointing out that the cooler the outside air, the more efficient your A/C will be.  Running the A/C in the middle of the day when it's 95 degrees requires more energy to expel X btus from the house than when it's only 85.  So by waiting until late afternoon to cool the house, you save even more.

I'll grant that it's nice to come to a nicely climate-controlled house.  But that's why you get a programmable thermostat.  Have it maintain 75 degrees (or whatever) from one hour before arrival, and switch to 95 degrees (so it basically turns off) one hour before you leave in the morning.  Now you get the savings from turning off your A/C during the day, and still come home to a cool house.

dragoncar

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Re: Overheard at Work
« Reply #18510 on: August 30, 2017, 12:29:02 PM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

"The EPA says it's better to shut off the air conditioner if you will be away for more than a few hours."
https://www.acdoctor.com/blog/turn-off-ac-or-leave-it-on/

* Assuming you live in a non-ridiculously hot area. I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.

No fucking way this is true.  It doesn't even make sense.  You just had a malfunctioning fridge that couldn't keep cold enough, or the efficiency difference between your fridge and AC unit was so disparate that no one should have been using that fridge (ie it was clearly malfunctioning). 

I also call bullshit on anyone saying it takes 3 days to recool their house or anything else.  It takes less energy to turn the AC or heater off/down while you are away and only run it while you are home, absolutely no exceptions.   You can make the argument that you are more comfortable for some short period by keeping a constant temperature rather than turning the unit off then back on and waiting for it to reach your ideal temperature, but leaving it on uses more total energy absolutely no exceptions ever.  That's just the laws of thermodynamics.

In this thread, there are two separate arguments:

1) it's cheaper to turn off the AC when you are gone.  I think this is true 99% of the time.  I actually have a corner case because I have a smart meter with "flex days" which basically means on certain high usage days the cost skyrockets ($1/kWh from 1pm-7pm).  These days are typically the hottest days.  We rarely use ac, but when we get a few super hot days in a row, night temps don't drop enough to cool our house so we close up the windows and precool the house in the morning while rates are low.  I know from experience that the house will gain 10-15 degrees on the hottest days, so if it starts off at 75-80, we are risking very uncomfortable temps in the late afternoon when it would cost a small fortune to tune AC.  So let's say we wake up and it's like 80 inside and the weather is looking to be 110. I'm going to turn on the AC and probably run it until we get down to 70 or it's 1pm which ever comes first.  Even if I leave the house I'm leaving the AC on. Because I don't want to come home at 1pm to a warm house and have to turn of the ac.  This scenario has happened maybe 1-2 times, but it's just an example of how energy pricing can mess up your standard assumptions

2) it's "better" to turn of the ac where "better" is some combination of cost and comfort.  I'd say this is where most of the so called "exceptions" come into play.  Even if it takes your house 3 full days to recover from the ac being off, it'll still be cheaper.  But most people will say it's not "better" because it would be uncomfortable. 

Another example would be if you have perishables that you can't keep in the fridge- expensive chocolates or wine or whatever.  If the house gets too hot they could be ruined.  Of course it would be cheaper to refrigerate them but if you don't have an extra wine fridge it could be cheaper to set the thermostat vs letting it all melt.  I had some chocolate melt on vacation but luckily it wasn't expensive and I just used it for baking.
« Last Edit: August 30, 2017, 12:32:53 PM by dragoncar »

frugalnacho

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Re: Overheard at Work
« Reply #18511 on: August 30, 2017, 12:30:51 PM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.
If it helps, you can think about A/C as a heat-removal machine.  The more heat it removes from your home, the higher your bill.  The other side of the equation is things that put heat into your home.  Appliances, computers, stoves, outside air, and of course, the sun.  Let's ignore the man-made stuff and the sun, and focus on the outside air.  The amount of heat that enters your home through the walls is proportional to the temperature difference between inside and outside.  Roughly speaking, you get twice as much energy entering your 75-degree home if it's 95 degrees outside (20 degree difference) vs 85 (10 degree difference).

Let's do a case studey: For simplicity's sake, let's say that during the 10 hours you're away from home for work, the average temperature outside is 85 degrees, and your thermostat is set at 75.  We'll compare two houses one where the A/C is left on during the day, and one where the A/C is turned off when you leave and turned on when you return.  Let's say that the houses are insulated so that when it's 10 degrees warmer outside, enough energy enters the home to increase interior temperatures by 1 degree per hour.  We'll call that amount of energy X btu/hour.  Whatever the total energy input into the houses over the 10 hours must be removed by the A/C.

For the A/C-always-on house, the calculation is simple: 10 hours * X btu/hour.

For the A/C-off-during-the-day house, the calculation is a bit more complex and probably involves calculus.  Roughly speaking, during the first hour, the house gains X btu, which causes the temperature to rise by 1 degree.  During the second hour, however, the temperature difference is only 9 degrees, so the energy gained is only 0.9X btus.  During the third hour, the delta-T is 8.1 degrees, so 8.1X btus are added, and so on.  By the end of the day, the temperature has risen 4.5 degrees, and the total energy gained is only about 6.5 * X btus. 

Now, this ignores other heat sources (sun, appliances, etc), but it's not a big deal--as they heat up the house faster, the delta T between inside and outside shrinks, and the house will gain less energy from the outside air.

It's also worth pointing out that the cooler the outside air, the more efficient your A/C will be.  Running the A/C in the middle of the day when it's 95 degrees requires more energy to expel X btus from the house than when it's only 85.  So by waiting until late afternoon to cool the house, you save even more.

I'll grant that it's nice to come to a nicely climate-controlled house.  But that's why you get a programmable thermostat.  Have it maintain 75 degrees (or whatever) from one hour before arrival, and switch to 95 degrees (so it basically turns off) one hour before you leave in the morning.  Now you get the savings from turning off your A/C during the day, and still come home to a cool house.

Not necessarily true.  An AC's efficiency is dependent on outside temperature.  It takes a lot less energy to move heat outside when it's only 70* outside as opposed to 100*.

bender

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Re: Overheard at Work
« Reply #18512 on: August 30, 2017, 12:34:27 PM »
Since I'm not always home at the same time, I prefer to under-do the "return home" setpoint of programmable thermostats.  Most programmable thermostats have 4 setpoints - here's what I do:

In the Summer, I either use manual mode or I set all 4 points to extreme temp (essentially off).  Programmable mode ensures that if I forget the AC on it will turn itself off at some point.  My system reacts fast enough that I'm only uncomfortable for a few minutes, and many times I'm comfortable at higher temps if the humidity isn't too bad.  So automatically turning on the AC is a waste for me.  Automatic shutoff is an insurance policy.

dragoncar

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Re: Overheard at Work
« Reply #18513 on: August 30, 2017, 12:40:11 PM »
  An AC's efficiency is dependent on outside temperature.  It takes a lot less energy to move heat outside when it's only 70* outside as opposed to 100*.

Admittedly I'm no expert in mechanical thermodynamics but...

Isn't ac efficiency also dependent on inside temperature?  Or more specifically the difference between inside and outside temperature.  My instinct tells me it will be more efficient to cool a 100 degree home when it's 109 outside than an 80 degree home when it's 85 outside.

So the more heat you remove the higher your bill, all things being equal.  You could be suggesting something along the lines of my precooling scenario above, where you run the ac in the morning when both inside and outside temps are 80, giving you little temperature gradient and maximum efficiency.  This is better than running in afternoon when temps are 90 inside and 110 outside, a 20 degree gradient.
« Last Edit: August 30, 2017, 12:44:53 PM by dragoncar »

frugalnacho

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Re: Overheard at Work
« Reply #18514 on: August 30, 2017, 12:45:03 PM »
In this thread, there are two separate arguments:

1) it's cheaper to turn off the AC when you are gone.  I think this is true 99% of the time.  I actually have a corner case because I have a smart meter with "flex days" which basically means on certain high usage days the cost skyrockets ($1/kWh from 1pm-7pm).  These days are typically the hottest days.  We rarely use ac, but When we get a few super hot days in a row, night temps don't drop enough to cool our house so we close up the windows and precook the house in the morning while rates are low.  I know from experience that the house will gain 10-15 degrees on the hottest days, so if it starts off at 75-80, we are risking very uncomfortable temps in the late afternoon when it would cost a small fortune to tune AC.  So let's say we wake up and it's like 80 inside and the weather is looking to be 110. I'm going to turn on the AC and probably run it until we get down to 70 or it's 1pm which ever comes first.  Even if I leave the house I'm leaving the AC on. Because I don't want to come home at 1pm to a warm house and have to turn of the ac.  This scenario has happened maybe 1-2 times, but it's just an example of how energy pricing can mess up your standard assumptions

2) it's "better" to turn of the ac where "better" is some combination of cost and comfort.  I'd say this is where most of the so called "exceptions" come into play.  Even if it takes your house 3 full days to recover from the ac being off, it'll still be cheaper.  But most people will say it's not "better" because it would be uncomfortable.

1. It uses less energy 100% of the time.  If you pay different rates for different time periods that's a separate issue and calculation.  It definitely could cost less money to keep it running depending on the different rates, but it will for sure use more energy.  We don't have tiered prices for different times.

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

dragoncar

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Re: Overheard at Work
« Reply #18515 on: August 30, 2017, 12:54:39 PM »
In this thread, there are two separate arguments:

1) it's cheaper to turn off the AC when you are gone.  I think this is true 99% of the time.  I actually have a corner case because I have a smart meter with "flex days" which basically means on certain high usage days the cost skyrockets ($1/kWh from 1pm-7pm).  These days are typically the hottest days.  We rarely use ac, but When we get a few super hot days in a row, night temps don't drop enough to cool our house so we close up the windows and precook the house in the morning while rates are low.  I know from experience that the house will gain 10-15 degrees on the hottest days, so if it starts off at 75-80, we are risking very uncomfortable temps in the late afternoon when it would cost a small fortune to tune AC.  So let's say we wake up and it's like 80 inside and the weather is looking to be 110. I'm going to turn on the AC and probably run it until we get down to 70 or it's 1pm which ever comes first.  Even if I leave the house I'm leaving the AC on. Because I don't want to come home at 1pm to a warm house and have to turn of the ac.  This scenario has happened maybe 1-2 times, but it's just an example of how energy pricing can mess up your standard assumptions

2) it's "better" to turn of the ac where "better" is some combination of cost and comfort.  I'd say this is where most of the so called "exceptions" come into play.  Even if it takes your house 3 full days to recover from the ac being off, it'll still be cheaper.  But most people will say it's not "better" because it would be uncomfortable.

1. It uses less energy 100% of the time.  If you pay different rates for different time periods that's a separate issue and calculation.  It definitely could cost less money to keep it running depending on the different rates, but it will for sure use more energy.  We don't have tiered prices for different times.


OK, so there's a third argument 3) it uses less energy 100% of the time.  Of course you are right, but my point is to be clear which thing you are arguing about.  There are threads explaining why it uses less energy, and people responding about how it's better.  I think we all can/should agree it uses less energy to turn off the AC.

Although, I think you should focus on price since this is the MMM forums.  CA has a lot of solar, and sometimes it is literally wasted or other states are paid to accept excess energy.  I would 100% spin up my AC during those times to avoid wastage except for being pissed doff my utility won't pass on the great deal to me and would likely charge me a surplus price.
« Last Edit: August 30, 2017, 12:56:18 PM by dragoncar »

dragoncar

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Re: Overheard at Work
« Reply #18516 on: August 30, 2017, 12:58:23 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

frugalnacho

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Re: Overheard at Work
« Reply #18517 on: August 30, 2017, 01:00:00 PM »
  An AC's efficiency is dependent on outside temperature.  It takes a lot less energy to move heat outside when it's only 70* outside as opposed to 100*.

Admittedly I'm no expert in mechanical thermodynamics but...

Isn't ac efficiency also dependent on inside temperature?  Or more specifically the difference between inside and outside temperature.  My instinct tells me it will be more efficient to cool a 100 degree home when it's 109 outside than an 80 degree home when it's 85 outside.

So the more heat you remove the higher your bill, all things being equal.  You could be suggesting something along the lines of my precooling scenario above, where you run the ac in the morning when both inside and outside temps are 80, giving you little temperature gradient and maximum efficiency.  This is better than running in afternoon when temps are 90 inside and 110 outside, a 20 degree gradient.

Yes it depends on both.  But "the more heat you remove the higher your bill" is not necessarily true, because the cost to remove a given unit of heat is variable.  So I guess my "no exceptions ever" statement might not be true either when it comes to AC...

If for some reason you had a cloud of hot ass air moving towards your house that would cause the outdoor temperature to jump 30*F in a matter of one minute you would be better off (use less energy, and less money) to run the AC and get your internal temperature down to an ideal spot before the hot air shows up, then not run it after the hot air gets there (because your house is already cooled) rather than inverting that.  Not really a realistic scenario though.  A much more likely scenario is the one you suggest of precooling the house when it's cooler outside, but the problem with that is that your house is not perfectly insulated.  You may be moving units of heat "cheaper" in the morning because it's more efficient, but you end up moving more units of heat total by precooling it and then maintaining that temperature.  The end result is that it still requires more energy to precool than it does to turn it off and on as needed. 

bender

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Re: Overheard at Work
« Reply #18518 on: August 30, 2017, 01:04:32 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

An AC running 24x7 will have a significantly shorter lifespan than one that cycles on/off reasonably.

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Re: Overheard at Work
« Reply #18519 on: August 30, 2017, 01:08:29 PM »

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.


This depends on what you mean by taking 3 days to recover. If you leave the AC off for 15 hours and then turn it on and it takes 3 days, yes there is a problem. But if your AC is off for 3 days and it takes 3 days to recover, that is normal in high heat situations.

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Re: Overheard at Work
« Reply #18520 on: August 30, 2017, 01:09:17 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

lol no one would say that.  I don't think you want a unit to run 24/7.  You probably want some where in the middle.  Also what if it gets a few degrees hotter? How does your AC handle that if it's already running 24/7?

Given that this is MMM this debate shouldn't even exist.  You probably aren't a perishable vegetable that needs to be refrigerated, so the most MMM thing would be to adapt to the summer weather.

frugalnacho

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Re: Overheard at Work
« Reply #18521 on: August 30, 2017, 01:12:56 PM »

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.


This depends on what you mean by taking 3 days to recover. If you leave the AC off for 15 hours and then turn it on and it takes 3 days, yes there is a problem. But if your AC is off for 3 days and it takes 3 days to recover, that is normal in high heat situations.

Where do you live, the sun?  I don't think it's normal for any place to take 3 days to recover and get down to room temperature if it has an appropriately sized AC. 

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Re: Overheard at Work
« Reply #18522 on: August 30, 2017, 01:15:25 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

No, this would be terrible for comfort. If you DO leave for a day, a week, or just want to turn it off when you're not home for 8 hours at work, you would be miserable when you do actually want it. If the unit is that undersized you would be waiting many hours to reach optimal temperature. A unit that runs 24/7 wouldn't be efficient, it would be undersized. You'd save a couple thousand on equipment costs but it wouldn't be worth the comfort/cost of running the unit when you're not home.

Maybe if you used window AC units in only the room you're currently occupying? That wouldn't be a bad strategy as far as money-saving, comfort, and equipment costs.

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Re: Overheard at Work
« Reply #18523 on: August 30, 2017, 01:36:30 PM »
Where do you live, the sun?  I don't think it's normal for any place to take 3 days to recover and get down to room temperature if it has an appropriately sized AC.

"Appropriately sized AC" along with insulation is the key. I used to live in a place with under-sized A/C and lousy insulation/leaky windows and doors, and it easily took over a day to cool down to a normal room temperature. And it was just an apartment which got very little direct sun, not a whole house or anything. My new place goes from Sahara > Antarctica in about an hour.
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Re: Overheard at Work
« Reply #18524 on: August 30, 2017, 01:41:03 PM »

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.


This depends on what you mean by taking 3 days to recover. If you leave the AC off for 15 hours and then turn it on and it takes 3 days, yes there is a problem. But if your AC is off for 3 days and it takes 3 days to recover, that is normal in high heat situations.

Where do you live, the sun?  I don't think it's normal for any place to take 3 days to recover and get down to room temperature if it has an appropriately sized AC.

No, just Chicago.

Earlier this summer, during the hottest week (of course it was the hottest week, when else does it happen?), we lost our AC. We put in a window unit in one room for the dogs, but we couldn't get the AC repaired for about 3-4 days. By that point, everything in the house was 90*, or close to it. Guess what? The repaired, efficient, correctly sized 5 year old AC in a house with good insulation took 3 days to get the house down from 90 to 72. It wasn't running the whole time--I'm guessing for efficiency reasons--but it took 3 days to cool the entire house down. Sure the area right by the thermostat was comfortable, but the upstairs was in the 80's for days 1 and 2. after the repair.

At one point I lived in a house with nearly no insulation and an undersized AC. That one required us to have a sprinkler on the house to help keep it cool. It never actually got cool, even though the AC was working correctly.

dragoncar

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Re: Overheard at Work
« Reply #18525 on: August 30, 2017, 02:00:38 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

lol no one would say that.  I don't think you want a unit to run 24/7.  You probably want some where in the middle.  Also what if it gets a few degrees hotter? How does your AC handle that if it's already running 24/7?

Given that this is MMM this debate shouldn't even exist.  You probably aren't a perishable vegetable that needs to be refrigerated, so the most MMM thing would be to adapt to the summer weather.

This guy would:

Quote
When outdoor conditions are at the design temperature, an air conditioner should run pretty much continuously and be able to keep the house at the ACCA recommended indoor design temperature of 75 degrees Fahrenheit

What if it gets hotter?  The idea is to run continuously at "design temperature."  Everything below that is gravy.


No, this would be terrible for comfort. If you DO leave for a day, a week, or just want to turn it off when you're not home for 8 hours at work, you would be miserable when you do actually want it. If the unit is that undersized you would be waiting many hours to reach optimal temperature. A unit that runs 24/7 wouldn't be efficient, it would be undersized. You'd save a couple thousand on equipment costs but it wouldn't be worth the comfort/cost of running the unit when you're not home.

Maybe if you used window AC units in only the room you're currently occupying? That wouldn't be a bad strategy as far as money-saving, comfort, and equipment costs.

Comfort would be improved because you wouldn't have the heat swings you get from the bang/bang thermostats.

You'd have to leave it on all the time, so you'd lose setback gains.  Probably more ideal for people who are home all day, like elderly retirees.

There are, however, efficiency gains.  The blower would be smaller with lower pressure and CFM, which is more efficient for the same total volume of air moved.  The AC would be smaller, and I believe wear and inefficiency are both higher on startup/shutdown, which would be eliminated with a 24 hour run time. 

Even better would be a variable speed compressor/blower that can adjust down from max design temperature as things cool off.  That would make the equipment more expensive of course.

Like I said, I hardly ever use AC anyways, since our house is almost never gets uncomfortably hot even on 100+ days.  But it's an interesting theoretical problem, although perhaps impossible to solve without doing actual math or real world tests vs the butt-math we are using here.

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Re: Overheard at Work
« Reply #18526 on: August 30, 2017, 02:19:34 PM »

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.


This depends on what you mean by taking 3 days to recover. If you leave the AC off for 15 hours and then turn it on and it takes 3 days, yes there is a problem. But if your AC is off for 3 days and it takes 3 days to recover, that is normal in high heat situations.

Where do you live, the sun?  I don't think it's normal for any place to take 3 days to recover and get down to room temperature if it has an appropriately sized AC.

No, just Chicago.

Earlier this summer, during the hottest week (of course it was the hottest week, when else does it happen?), we lost our AC. We put in a window unit in one room for the dogs, but we couldn't get the AC repaired for about 3-4 days. By that point, everything in the house was 90*, or close to it. Guess what? The repaired, efficient, correctly sized 5 year old AC in a house with good insulation took 3 days to get the house down from 90 to 72. It wasn't running the whole time--I'm guessing for efficiency reasons--but it took 3 days to cool the entire house down. Sure the area right by the thermostat was comfortable, but the upstairs was in the 80's for days 1 and 2. after the repair.

At one point I lived in a house with nearly no insulation and an undersized AC. That one required us to have a sprinkler on the house to help keep it cool. It never actually got cool, even though the AC was working correctly.

If I understand how this system works, the issue is that the thermostat was signalling that the building was cool, so the AC stopped cooling. Then warmer air gradually drifted and heated the area near the thermostat, and got cooled, and so on. It was the air movement that took the time. If it happens again, see if running a $20 fan to move the air around the house helps.

mtn

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Re: Overheard at Work
« Reply #18527 on: August 30, 2017, 02:43:09 PM »

2.  I tried to keep to to a an actual energy usage basis rather than making a judgement call about "better" or not.  That's a value judgement everyone has to make for their own situation.  But if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.


This depends on what you mean by taking 3 days to recover. If you leave the AC off for 15 hours and then turn it on and it takes 3 days, yes there is a problem. But if your AC is off for 3 days and it takes 3 days to recover, that is normal in high heat situations.

Where do you live, the sun?  I don't think it's normal for any place to take 3 days to recover and get down to room temperature if it has an appropriately sized AC.

No, just Chicago.

Earlier this summer, during the hottest week (of course it was the hottest week, when else does it happen?), we lost our AC. We put in a window unit in one room for the dogs, but we couldn't get the AC repaired for about 3-4 days. By that point, everything in the house was 90*, or close to it. Guess what? The repaired, efficient, correctly sized 5 year old AC in a house with good insulation took 3 days to get the house down from 90 to 72. It wasn't running the whole time--I'm guessing for efficiency reasons--but it took 3 days to cool the entire house down. Sure the area right by the thermostat was comfortable, but the upstairs was in the 80's for days 1 and 2. after the repair.

At one point I lived in a house with nearly no insulation and an undersized AC. That one required us to have a sprinkler on the house to help keep it cool. It never actually got cool, even though the AC was working correctly.

If I understand how this system works, the issue is that the thermostat was signalling that the building was cool, so the AC stopped cooling. Then warmer air gradually drifted and heated the area near the thermostat, and got cooled, and so on. It was the air movement that took the time. If it happens again, see if running a $20 fan to move the air around the house helps.

No, it is central AC with air going to all rooms evenly. What happens is that the air is cooled down, but it takes a long time to cool down the walls, couches, counters, beds, etc. So the air is cooled, but then warmed by the rest of the house.

It is much, much easier to keep something cold or keep something warm than it is to make it cold or make it warm.

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Re: Overheard at Work
« Reply #18528 on: August 30, 2017, 03:28:59 PM »
if your house is taking 3 days to recover and cool down you either have an over sized house or an undersized AC unit and you should probably worry about that rather than whether to run your undersized AC 24/7 or not.

some would say your AC is perfectly sized if it runs 24/7 and maintains a comfortable temperature.  Is it better to have an oversized AC that can cool your house in 2 hours and then cycles on and off, or a much smaller, more efficient unit that runs 24/7?  I said better, but I'm open to answers for energy usage, total cost including equipment, and comfort.

lol no one would say that.  I don't think you want a unit to run 24/7.  You probably want some where in the middle.  Also what if it gets a few degrees hotter? How does your AC handle that if it's already running 24/7?

Given that this is MMM this debate shouldn't even exist.  You probably aren't a perishable vegetable that needs to be refrigerated, so the most MMM thing would be to adapt to the summer weather.

This is what I do, but I'm in a moderate climate. It's different when you're in the desert or something.

Where I live, it doesn't get any hotter than 90-95 degrees F in the hottest weeks of the year. When I close the curtains on the sunny side of the house, it means it gets up to about 80 F inside the house and for a few weeks a year, you can easily survive that.

During winter, we do it the other way round and let it cool to about 65 F before we put on the heating. In a moderate climate where winter temperatures vary between 20 and 50 F, that means we barely have any heating costs and no cooling costs at all. We have a portable fan from when we lived in a top floor apartment that we've been hanging on to 'just in case' but we could just as well declutter that. 

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Re: Overheard at Work
« Reply #18529 on: August 30, 2017, 03:52:42 PM »
It is much, much easier to keep something cold or keep something warm than it is to make it cold or make it warm.

The problem with that argument is that if your walls and furniture have so much thermal mass that they take forever to cool back down, then they're also going to take forever to warm up after you turn the air off.  It's not like you turn the air off at 8 when you leave for work and at 9am everything in your house has normalized to 95F.  First the air has to warm up, which takes time, then everything else follows behind it.  If all your stuff has enough thermal mass to have to keep it in consideration, then it's still going to be cool when you get home from work, helping to keep the house cool throughout the day.

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Re: Overheard at Work
« Reply #18530 on: August 30, 2017, 05:01:54 PM »
It is much, much easier to keep something cold or keep something warm than it is to make it cold or make it warm.

The problem with that argument is that if your walls and furniture have so much thermal mass that they take forever to cool back down, then they're also going to take forever to warm up after you turn the air off.  It's not like you turn the air off at 8 when you leave for work and at 9am everything in your house has normalized to 95F.  First the air has to warm up, which takes time, then everything else follows behind it.  If all your stuff has enough thermal mass to have to keep it in consideration, then it's still going to be cool when you get home from work, helping to keep the house cool throughout the day.
Seriously guys, don't make me dig out my engineering manuals and math.  Actually, the main manual is propping up my 2nd monitor.

So, I should be working, but I googled.  A few places on the interwebs note that heating and cooling do not happen at the same rate.  (Heating comes from adding energy, cooling from removing energy.  It's harder to remove energy than add it because of entropy.)

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Re: Overheard at Work
« Reply #18531 on: August 30, 2017, 05:05:37 PM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

By that logic, you should just leave the oven on all day so it doesn't have to heat up from room temperature when it's time to make dinner.

Not quite the same logic, actually.

When our AC was out for a couple of days, it took about 3 days to get the house back cool. Why? Because everything in the house was hot. The couches, walls, floors, beds, tables, everything was over 90*. So the air was cooled, but the things were not.

It doesn't take very long to heat 5 cubic feet of air. It takes a LONG time to cool/heat a lot of things, and air.

I'm not saying he's right--but he has a valid, though mis-led point.

three days seems extreme.

Where I work we regularly have days over 48C during the day (google tells me this is 118F) and it wont drop below 30C over night  (86F) I am probably the only person who I work with who doesnt leave my aircon all day while I am at work. It doesnt take that long for me to get it back to a regular temperature, I put it on 24C when I get back and its fine. Admittedly my accommodation at work is small but it doesnt take long for the place, including bed, couch, other furniture to cool down.

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Re: Overheard at Work
« Reply #18532 on: August 30, 2017, 05:28:33 PM »
I'm old enough to remember when this was the Overheard at Work thread.


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Re: Overheard at Work
« Reply #18533 on: August 30, 2017, 05:56:40 PM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

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Re: Overheard at Work
« Reply #18534 on: August 30, 2017, 07:16:44 PM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

Well done! I hope to have a similar amount as you and also be retired by that age, though maybe not long retired


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TexasStash

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Re: Overheard at Work
« Reply #18535 on: August 30, 2017, 07:17:17 PM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

Well done! I hope to have a similar amount as you and also be retired by that age, though maybe not long retired


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TexasStash

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Re: Overheard at Work
« Reply #18536 on: August 30, 2017, 07:18:41 PM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

Well done! I hope to have a similar amount as you and also be retired by that age, though maybe not long retired


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TexasStash

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Re: Overheard at Work
« Reply #18537 on: August 30, 2017, 07:17:50 PM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

Well done! I hope to have a similar amount as you and also be retired by that age, though maybe not long retired


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Playing with Fire UK

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Re: Overheard at Work
« Reply #18538 on: August 31, 2017, 12:16:57 AM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

That's a neat way of explaining it. Not necessarily the final value but the concept (while still MMM-light), is achievable for many.

TartanTallulah

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Re: Overheard at Work
« Reply #18539 on: August 31, 2017, 02:58:48 AM »
Yesterday a kind coworker told me "if you pay yourself first and save one hour of each day's paycheck, by the time you're my age [54], you could have $500k!"

I smiled because she had really good advice and knew what she was talking about. Of course I didn't tell her by the time I'm her age I'll have three times that amount (hopefully) and be long retired!

I think that's quite lovely advice, and could be a very apt image for making the concept of regular saving real to people whose minds work that way. I wouldn't hesitate to offer advice like that to my young co-workers, taking the risk that some of them may already be socking away 70% of their income.



LennStar

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Re: Overheard at Work
« Reply #18540 on: August 31, 2017, 03:09:09 AM »
No, it is central AC with air going to all rooms evenly. What happens is that the air is cooled down, but it takes a long time to cool down the walls, couches, counters, beds, etc. So the air is cooled, but then warmed by the rest of the house.

It is much, much easier to keep something cold or keep something warm than it is to make it cold or make it warm.

Yes, look at The Mustache himselfs posts when he writes about the thermal mass of his new home. Or have a look at earthships which use a passive heat storing system to cool in the summer and heat warm in the winter.

Not overheard the earthships at my work, but I COULD HAVE.

barbaz

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Re: Overheard at Work
« Reply #18541 on: August 31, 2017, 04:04:26 AM »
It is much, much easier to keep something cold or keep something warm than it is to make it cold or make it warm.

Yes, look at The Mustache himselfs posts when he writes about the thermal mass of his new home.
1) Thermal mass helps to smooth the temperature curve without using artificial heating/cooling, but when you use devices, then turning them off will always save energy, because during the time when the temperature difference is reduced you will have less heat flow between inside and outside. Whether that's cost-effective, comfortable, or "easier" depends on a whole lot of other factors though.

2) Going back to the preferred temperature should always take less time than the device was turned off. Otherwise, how were you able to maintain the temperature in the first place? The only exception is when the heating/cooling device cannot run non-stop.

3) The only interesting question arises in the scenario described by RidetheRain
I live in the desert and if I turn off the a/c while I'm at work then my fridge has to work overtime because of the heat. I end up with a ridiculously high bill because of the fridge and any food in the door goes bad (I hide dairy in the back corner to this day). For me, just cooling the place is cheaper although I do have different temps for when I'm home vs not home.
Does this mean the fridge sucks or is it normal that AC units are more energy efficient than fridges?

Feivel2000

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Re: Overheard at Work
« Reply #18542 on: August 31, 2017, 05:09:24 AM »
I once had an AC that pushed out foam instead of cold air.

Only solution was to turn it off and move it to the room for the foam party. This way people could enjoy the foam and my work room was almost foam free.


87tweetybirds

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Re: Overheard at Work
« Reply #18543 on: August 31, 2017, 05:39:02 AM »
Long time lurker of this post, but I don't think I've posted before

Not really overheard, but work related. My employer produces a quarterly "flyer" that has your benefits and investment info, basically telling you how much money the company has spent on your benefits, how much you have spent on benefits, etc, but there is also a part that is called "your FIt age. Financially Independent time? I think- it's the soonest they think you will have saved enough to retire at your current rate. I noticed it said "55", and I thought, no way, I should be FI before that, then I noticed the small writing below it says something like, "55 is the earliest our software will compute a retirement age" So I guess the company doesn't think its possible to Retire very early.

And then, not at work, but my Brother (#3) and SIL are pretty deep into debt with student loans, she recently had her laptop computer "die", and they bought a new one-with $ from their student loans that they'll be paying on for the rest of her life. She gave the laptop to one of my brothers(#2), who isn't in a tech field, but is pretty computer savy. (I'm not super tech savy) He told me he had to do a couple of things, and then reinstall the software, but was able to bring the laptop back to life. He offered it back to my SIL, but she said, "Oh, I don't need it, we already bought a new one." Now granted she's in school and may have needed a computer, but I know brother #3 has a laptop, and they have a desktop, so it's not like she didn't have other options while it was being worked on. Oh well, my brother #2 was thrilled to have acquired a "free" laptop.

Rollin

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Re: Overheard at Work
« Reply #18544 on: August 31, 2017, 05:47:39 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

I remember that the Florida Solar Energy Center website had something on this (BTW you are correct). Maybe take the easy road in explanation though and tell him with his theory he should leave his car running all day (while at work of course) with the AC on.
I love being outside.

marty998

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Re: Overheard at Work
« Reply #18545 on: August 31, 2017, 06:12:11 AM »
I once had an AC that pushed out foam instead of cold air.

Only solution was to turn it off and move it to the room for the foam party. This way people could enjoy the foam and my work room was almost foam free.

I see what you did there ;)

I also think everyone needs to practice badassity and not use aircon at all.

wauske

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Re: Overheard at Work
« Reply #18546 on: August 31, 2017, 10:22:44 AM »
One of my colleagues strongly believes that it is less expensive to run his A/C the whole day while he's at work, than to turn it off when he leaves, then back on again.

Because, he says, it uses more energy to start the cooling process over again and cool the room, than to maintain a given (cold) room temperature. I'm pretty sure that's ignoring very basic principles of thermodynamics. Appreciate if any of you have a concise, yet authoritative site on the topic.

By that logic, you should just leave the oven on all day so it doesn't have to heat up from room temperature when it's time to make dinner.

Not quite the same logic, actually.

When our AC was out for a couple of days, it took about 3 days to get the house back cool. Why? Because everything in the house was hot. The couches, walls, floors, beds, tables, everything was over 90*. So the air was cooled, but the things were not.

It doesn't take very long to heat 5 cubic feet of air. It takes a LONG time to cool/heat a lot of things, and air.

I'm not saying he's right--but he has a valid, though mis-led point.
The same applies when you're hearing too, when you come back from a holiday mid winter and your house is cold the air is easy to heat but the other stuff needs to heat up as well. Depending on you house's insulation it can actually be better to keep a certain temperature constantly rather than lower the temp dramatically and reheating it a few hours later...
Everything I say is my personal opinion which is based on my subjective experience.

Raenia

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Re: Overheard at Work
« Reply #18547 on: August 31, 2017, 10:31:38 AM »
Just had a really sad "overheard at work" to share.  My employer runs a shuttle from the site to the train station for employees who take public transit.  From what I can tell, the company hires a contractor company, who in turn hires the driver (and probably provides the van?)  Two of my coworkers to take the train were talking about it, and apparently the guy who drives the van told them that he has to drive 180 miles each way to get from his home to the site, over 2 hours of unpaid driving before he even gets to work.  Apparently he's been sleeping in the van in the parking lot some night because he was too exhausted to drive home.  He's getting older and having some health concerns which might make it dangerous for him to drive, but no one is taking action.  And to top it off, he was recently asking for advice on his legal rights when his paycheck from the contract company bounced when he tried to cash it- which has apparently happened multiple times!

This poor guy cannot possibly be paid enough to make this gig worthwhile.

Debts_of_Despair

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Re: Overheard at Work
« Reply #18548 on: August 31, 2017, 10:51:35 AM »
Pretty common in the transportation industry.  If you aren't driving "loaded" miles you might not be getting paid.

RyanAtTanagra

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Re: Overheard at Work
« Reply #18549 on: August 31, 2017, 11:05:33 AM »
Depending on you house's insulation it can actually be better to keep a certain temperature constantly rather than lower the temp dramatically and reheating it a few hours later...

Still faulty logic.  If your insulation is so bad that the temp of the house changes dramatically while you're at work, that means it's also bad enough that your a/c or heater is going to be working hard all day to keep a constant temp while no one is there.