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Learning, Sharing, and Teaching => Ask a Mustachian => Topic started by: Case on December 10, 2018, 07:12:13 AM

Title: minimum safe house temperature for when away at work
Post by: Case on December 10, 2018, 07:12:13 AM
There are other threads on this, I know.  I've looked through then.  I'd like to keep this concentrated on a particular topic which I think is worth revisiting, and probably relevant to most people.

My house temperature cycles as follows: thermostat to 55 F when away at work, and then spike up to 66 F for when active in the house, and for 62 F at bed time.  I want to optimize.

From an efficiency standpoint, I would think the temperature should be as low as possible when unoccupied, as long as it's not so cold that the pipes freeze and our cat is significantly uncomfortable.  From what I've read, cats/pets have fur and so are totally fine within any typical human indoor temperatures.  Pipes freezing is variable and depends on the location in your house and insultion/etc.  My pipes are mostly exposed and insulation in reasonably good... no pipes are located inside exterior walls; I do have pipes in a underhouse crawlspace, and I monitor the temperature.  So, I'm not so concerned about pipes freezing.

What I am thinking about is the effect of more extremely temperature cycling on the house and whether this will cause bad things.  For example, constant expanding/contracting of the building materials, and cycling humidity levels.

Along this lines, any thoughts/experience on the lowest practical away-from-house temperatures?

Title: Re: minimum safe house temperature for when away at work
Post by: Rosy on December 10, 2018, 07:35:23 AM
We stick to 80 degrees in summer when away from the house and in winter simply shut off the heat while we are gone.
Our pipes are less than ideal and some are exposed and not insulated.
The few days when temps have dropped to the 30's for a few hours at night, maybe two days a year if at all, haven't caused any problems.

For us, the problem is the heat. Mold will occur if the house is shut down tight with no AC on at all. Florida is bug country, no telling what infestations will occur if the house is simply closed up.
The AC will definitely run in the summer even if we set it at 85, we choose to go with 80 degrees.
For us, simply being able to open the window and have cool fresh air coming in is, like today:) is a blessing. 
Title: Re: minimum safe house temperature for when away at work
Post by: Bracken_Joy on December 10, 2018, 07:48:55 AM
Yeah depending on where you are, it's either the cold or the humidity that'll cause problems. Age of house, whether you have a basement, etc can also play a role. Age of your pet matters too- older mammals have their skin and body fat layers thin out, and are less cold tolerant.

Which is to say, there's really no easy answer to this!
Title: Re: minimum safe house temperature for when away at work
Post by: GuitarStv on December 10, 2018, 07:54:52 AM
Turn off the water mains valve to your home and then drain all the pipes.  Then you can confidently turn the heat down to just above freezing without worrying about burst pipes.
Title: Re: minimum safe house temperature for when away at work
Post by: I'm a red panda on December 10, 2018, 07:55:49 AM
We keep our thermostat on 55 when we are gone in the winter. We used to do 50; but then we put a thermometer in the basement and found rooms as cold as 35. Which meant that areas we couldn't measure might be colder, and that was getting awfully close to freezing pipes!   I'd rather pay a heating bill than redo all the plumbing, dry wall, and flooring due to burst pipes.  If we are gone for extended periods, we turn the water line off; but even just being gone for the day, I don't want it getting too low.

In the summer we leave it at 82; higher than that the humidity gets so insane I worry about the house.
Title: Re: minimum safe house temperature for when away at work
Post by: Morning Glory on December 10, 2018, 08:49:20 AM
We turn ours down to 50 when we go away for vacation, and it gets as low as -20F here. No problems except one time some soda froze and exploded in an unheated coat closet located in a poorly insulated part of the house that had once been a porch.
Title: Re: minimum safe house temperature for when away at work
Post by: dcheesi on December 10, 2018, 08:58:27 AM
The highest I'll go in the summer is 77F (25C), since that's the top of the rated storage temperature for some medications etc. On the low end, I try to keep it at 60 or above, but I've had it go colder than that (mostly when the power was out) with no problems. 60 is more comfortable for my cats, and in my old place it the thermostat was upstairs, so it actually got colder than that in the basement. In my new apartment I'm on the top floor, so my heating bill is never as large as my A/C bill in the summer anyway.
Title: Re: minimum safe house temperature for when away at work
Post by: frugalnacho on December 10, 2018, 10:19:56 PM
I've found you get rapidly diminishing returns.  If your house is 62 at night and 55 when unoccupied, realistically how high is your heating bill even in the dead of winter?


Title: Re: minimum safe house temperature for when away at work
Post by: MrSal on December 11, 2018, 07:20:45 AM
I turn off the heat when away for long periods with emergency temperature kick in at 44F.

We keep at 66-67F when active and 59-60 when sleeping.

We live in Central PA so it's cold here... Low teens for lows and high 20s for highs. Since we have insulated the house pretty well recently the house rarely dips below 60...

Our average heating usage the past few cold days has been about 2.5 hours of heat usage per day
Title: Re: minimum safe house temperature for when away at work
Post by: Case on December 11, 2018, 05:29:19 PM
I've found you get rapidly diminishing returns.  If your house is 62 at night and 55 when unoccupied, realistically how high is your heating bill even in the dead of winter?

Just moved in so still establishing a baseline....
Title: Re: minimum safe house temperature for when away at work
Post by: Case on December 11, 2018, 05:35:08 PM
There are other threads on this, I know.  I've looked through then.  I'd like to keep this concentrated on a particular topic which I think is worth revisiting, and probably relevant to most people.

My house temperature cycles as follows: thermostat to 55 F when away at work, and then spike up to 66 F for when active in the house, and for 62 F at bed time.  I want to optimize.

From an efficiency standpoint, I would think the temperature should be as low as possible when unoccupied, as long as it's not so cold that the pipes freeze and our cat is significantly uncomfortable.  From what I've read, cats/pets have fur and so are totally fine within any typical human indoor temperatures.  Pipes freezing is variable and depends on the location in your house and insultion/etc.  My pipes are mostly exposed and insulation in reasonably good... no pipes are located inside exterior walls; I do have pipes in a underhouse crawlspace, and I monitor the temperature.  So, I'm not so concerned about pipes freezing.

What I am thinking about is the effect of more extremely temperature cycling on the house and whether this will cause bad things.  For example, constant expanding/contracting of the building materials, and cycling humidity levels.

Along this lines, any thoughts/experience on the lowest practical away-from-house temperatures?

I guess what im wondering is, at what point does expansion/contraction of construction materials (and wood floors) start to be affected negatively by large temperature swings?
Title: Re: minimum safe house temperature for when away at work
Post by: secondcor521 on December 11, 2018, 06:29:59 PM
There are other threads on this, I know.  I've looked through then.  I'd like to keep this concentrated on a particular topic which I think is worth revisiting, and probably relevant to most people.

My house temperature cycles as follows: thermostat to 55 F when away at work, and then spike up to 66 F for when active in the house, and for 62 F at bed time.  I want to optimize.

From an efficiency standpoint, I would think the temperature should be as low as possible when unoccupied, as long as it's not so cold that the pipes freeze and our cat is significantly uncomfortable.  From what I've read, cats/pets have fur and so are totally fine within any typical human indoor temperatures.  Pipes freezing is variable and depends on the location in your house and insultion/etc.  My pipes are mostly exposed and insulation in reasonably good... no pipes are located inside exterior walls; I do have pipes in a underhouse crawlspace, and I monitor the temperature.  So, I'm not so concerned about pipes freezing.

What I am thinking about is the effect of more extremely temperature cycling on the house and whether this will cause bad things.  For example, constant expanding/contracting of the building materials, and cycling humidity levels.

Along this lines, any thoughts/experience on the lowest practical away-from-house temperatures?

I guess what im wondering is, at what point does expansion/contraction of construction materials (and wood floors) start to be affected negatively by large temperature swings?

I don't know, but I personally wouldn't worry about my house construction materials between freezing and, say 120 degrees Fahrenheit.

I think the limiting factors would be:

1.  Not letting your pipes freeze (unlikely even if you turned your heat off while you're at work, unless you live in Alaska and do 12 hour shifts),
2.  Your cat's comfort, and
3.  The time it takes to reheat your home up to a comfortable temperature when you get home after work.
Title: Re: minimum safe house temperature for when away at work
Post by: bacchi on December 11, 2018, 07:45:21 PM
Get a cat heating pad, set the house to 55, and you're good.
Title: Re: minimum safe house temperature for when away at work
Post by: Radagast on December 11, 2018, 07:48:43 PM
How cold can your house even get in 12 or so hours? My house will not drop below 50 on a day with a high of 0 even if I set the heat to off, and I would rate it’s heating and air sealing as very average (R40ish ceiling, maybe R7ish walls, air sealing some variant of “meh”). It is alarming to hear everything popping when the heat comes back on though. In practice I also find the objects in the house retain their colder temperature for a long time after hot air starts to blow through the house which makes it feel much colder than the air temperature so I ended up keeping it at 60 if I will be back that evening. Down to 40 for a long absence.