Author Topic: Efficiency / appliance question  (Read 717 times)

jgoody

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Efficiency / appliance question
« on: March 04, 2019, 12:09:23 PM »
I've got an efficiency/energy question for the engineering folks.  I have a relatively large espresso machine that takes a good 20 minutes to really warm up in the morning.  I love a cappuccino first thing in the morning, so I have it on a timer so it's ready to go when I wake up.  On the weekend, I will often have more than one cup at random times extending from morning until late afternoon, so I tend to just leave it on during the weekend daylight hours.  While I love the convenience of this, I've always been troubled by the electricity usage/waste of keeping the thing fired up.  But then I got to thinking, isn't the vast majority of electricity usage/waste from this appliance just helping heat my house?  Do I really need to sweat this issue at all in the Winter?  Obviously, it's a different scenario in the Summer, but can I at least assuage my guilt this time of year?

Prairie Stash

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Re: Efficiency / appliance question
« Reply #1 on: March 04, 2019, 03:48:04 PM »
Do you normally heat your house with electricity? If you do then its similiar to your main heat source.

If you use natural gas, it's about 15% of the cost to heat your house (on a pure heat basis); so your only wasting 85% of your money... This is similiar to the debate people had when incandescents were phased out, for the vast majority of people its an inefficient way to heat the house.

Although heat is the same no matter the source, it doesn't all cost the same to produce.

This isn't likely your biggest energy waste, most people have other phantom loads. You could try offsetting it by finding other reductions in an effort to assuage the guilt, I didn't mean to make you feel worse, I'm sorry if I ruined your cappucino this weekend.

jgoody

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Re: Efficiency / appliance question
« Reply #2 on: March 04, 2019, 09:34:09 PM »
Aw man... now my cappuccino is ruined :-)  Seriously, thanks for the reply.  We do heat our house with electricity.  We have a heat pump, though rarely use it for cooling in the summer.  We usually set the thermostat to only kick the AC on above like 84 and our house rarely exceeds that on even the hottest days. 

Where should I look for the worst offending "phantom loads" elsewhere in the house?  I recall renting a Kill-a-Watt once from the library years ago and hooking it up to a number of my appliances, but just not being surprised by any of them.  If anything, I recall being vaguely surprised that some of the appliances from the 80s and 90s fared just fine relative to the new energy star models.  Might not be the case for 50s or 60s era appliances...

HipGnosis

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Re: Efficiency / appliance question
« Reply #3 on: March 05, 2019, 10:15:45 AM »
some of the appliances from the 80s and 90s fared just fine relative to the new energy star models.
I find this very hard to believe.
I watched an info-news show last weekend that said current washers and refrigerators only use about 10% of the energy of 10 yr old models.

Prairie Stash

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Re: Efficiency / appliance question
« Reply #4 on: March 05, 2019, 12:56:13 PM »
If you are super ambitious/extreme I found my microwave is a (small) phantom, its the LED display. Gaming consoles, stuff that has standby modes, is also a common one, standby means power is being used waiting for signals.

The solution is a cheap digital timer turning it off overnight or a power bar for stuff that's rarely used. The alternative was a kill switch (off/on) but that requires more effort on a regular basis and I like automated stuff.

Most of the stuff I found was $2-5/year, its not getting rich money. Its purely curiosity that made me do it, but if you think a cappucino maker is bad then maybe your inclined to be inquisitive.

I asume the heat pump is fairly cheap to operate compared to the heat output, although it runs on electricity its not getting its Heat energy that way. There's probably some BTU/Therms/Heat output rating on it; you can compare costs/unit of heat which is what really matters, the trouble is getting everything into comparable units. For example 1 kwh is roughly 3400 Btu and a therm is 100,000 btu (now we have electricity and gas in the same units of BTU!). A therm (I think thats what americans use) costs approx. $0.60 while a kwh costs $0.15, so you see its better to heat with gas than electricity. Thats more math than you probably wanted.

But how many BTUs is your heat pump yielding per dollar of electricity it uses? That one eludes me but I bet you have some sort of rating on it and its cheaper than pure electric heat (or you would heat with pure electric...)

Cadman

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Re: Efficiency / appliance question
« Reply #5 on: March 06, 2019, 12:37:39 PM »
some of the appliances from the 80s and 90s fared just fine relative to the new energy star models.
I find this very hard to believe.
I watched an info-news show last weekend that said current washers and refrigerators only use about 10% of the energy of 10 yr old models.

When it comes to electrical usage, the old appliances were generally just as efficient as new ones, in some cases more so due to extensive insulation use. With one glaring exception....late 60's and 1970's frost-free refrigerators. So...many...heating elements.

Now, when it comes to hot water usage, modern dishwashers and clothes washers do use a lot less hot water, but at the expense of runtime and power usage. I also don't like the idea of replacing them every few years..not only for the waste but also the environmental cost to produce those new goods in China and transport them half way across the world.

To the OP, the price has really come down on Kill-a-watts to the point you might consider buying one outright. Out of curiosity, what's the wattage on that coffee maker?

jgoody

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Re: Efficiency / appliance question
« Reply #6 on: March 07, 2019, 11:42:53 AM »
To the OP, the price has really come down on Kill-a-watts to the point you might consider buying one outright. Out of curiosity, what's the wattage on that coffee maker?

I just checked the label and it says 1.45 KW, 13 A.  It is a pretty large machine, so I was surprised when I looked up a little Mr Coffee Espresso machine and found mine is only about 50% bigger in terms of wattage.

As for the Kill-a-watt, it just seems an unnecessary item to own for me.  My use would consist of plugging things into it for a day each, collecting the data, and then taking action on that data (if appropriate).  I can easily finish all of that in a month and then return it to the library for someone else to use.  Plus then I don't have to store it.

jgoody

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Re: Efficiency / appliance question
« Reply #7 on: March 07, 2019, 12:10:34 PM »
some of the appliances from the 80s and 90s fared just fine relative to the new energy star models.
I find this very hard to believe.
I watched an info-news show last weekend that said current washers and refrigerators only use about 10% of the energy of 10 yr old models.

Two thoughts on this. 
1.) I was wrong about the age of some of my appliances.  Though my fridges may LOOK like they were purchased in the 80s or 90s, I checked the tags and they are actually from '02 and '06. 

2.) That's still > 10 yrs old and their energy usage was nowhere near 10X the new energy star appliances.  Your info-news show was grossly blowing the energy differences out of proportion at least with regards to refrigerators.  There is money to be made in selling new appliances.  I think some degree of skepticism is in order.  I also dislike the idea of dumping these massive appliances into the landfill every 10 years. 
« Last Edit: March 07, 2019, 12:13:57 PM by jgoody »

robartsd

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Re: Efficiency / appliance question
« Reply #8 on: March 07, 2019, 12:23:42 PM »
Aw man... now my cappuccino is ruined :-)  Seriously, thanks for the reply.  We do heat our house with electricity.  We have a heat pump, though rarely use it for cooling in the summer.  We usually set the thermostat to only kick the AC on above like 84 and our house rarely exceeds that on even the hottest days. 
The appliance is converting 100% of the electricity it uses into heat within your home. The heat pump collects heat from outside and moves it into your home. The heat pump should be many times more efficient at heating your home than the appliance is.

I just checked the label and it says 1.45 KW, 13 A.  It is a pretty large machine, so I was surprised when I looked up a little Mr Coffee Espresso machine and found mine is only about 50% bigger in terms of wattage.
I would expect the machine to use close to the full rating when warming up (so a bit less than .5 kWh to fully warm up if it takes 20 minutes), but drop down in usage once up to temperature.

As for the Kill-a-watt, it just seems an unnecessary item to own for me.  My use would consist of plugging things into it for a day each, collecting the data, and then taking action on that data (if appropriate).  I can easily finish all of that in a month and then return it to the library for someone else to use.  Plus then I don't have to store it.
Yes, borrow the Kill-A-Watt from the library. Let the machine warm up fully, then check how much energy was used. Leave it on for an hour and see how much additional energy was used. This will let you calculate how expensive it is to have the all day convenience on the weekend. Of course if you did turn it off after your first cup, then came back and turned it on for a second cup a few hours later, it might not have cooled down completely, so the energy needed to bring it back online would be less than the initial warm up.

Something else to consider is that the warm up time (and energy use) probably depends on how much water is in it. If it has enough water for 4 cups, it will take nearly 4x the energy to warm up as it would if it had just enough for 1 cup. Energy required to hold the water at ready temperature is likely pretty similar regardless of water level (and may actually require slightly more energy as water level goes down).

Cadman

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Re: Efficiency / appliance question
« Reply #9 on: March 07, 2019, 12:50:04 PM »
To the OP, the price has really come down on Kill-a-watts to the point you might consider buying one outright. Out of curiosity, what's the wattage on that coffee maker?

I just checked the label and it says 1.45 KW, 13 A.  It is a pretty large machine, so I was surprised when I looked up a little Mr Coffee Espresso machine and found mine is only about 50% bigger in terms of wattage.

As for the Kill-a-watt, it just seems an unnecessary item to own for me.  My use would consist of plugging things into it for a day each, collecting the data, and then taking action on that data (if appropriate).  I can easily finish all of that in a month and then return it to the library for someone else to use.  Plus then I don't have to store it.

I'd find it hard to believe it would use 1.45KW for any extended period, so a KaW would definitely be in order.

Good points on storage, etc. I ended up buying my own to gather week-long data on different fridges, AC units, and other cyclic loads. For the big stuff, I pull the breaker panel cover and use a current clamp and Fluke meter, but that's overkill for many.