Today, I had my furnace guy come for the annual check-up, cleaning etc. I've known the guy for many years. I was telling him that next year we would be spending winter in the South and was planning on setting my furnace thermostat at 50 Degrees. He advised me not to do that. He said 60 Degrees minimum for my high efficiency furnace. He said moisture will accumulate in the heat exchanger if the furnace doesn't cycle enough and get hot enough. The life of the furnace will be reduced. I had never heard of that before. He said to think about it like a car exhaust. If all you do is drive it to the store and back, the exhaust never gets hot enough to evaporate the moisture and it rusts prematurely. He said the same thing happens with these high efficiency furnaces. So what do you think? What type of heating system do you have and what temperature do you leave your thermostat set to when away?

It may depend on your location, We have set ours between 50 - 55 degrees the past 15 years and no problem yet but it is an 80 year old house in northern MN and even at that temperature it runs plenty.

This can be a real problem.Since there is no good way to tell if it will affect YOU or not, I suggest that you take the advice of an "expert".Also....there might be some nooks and crannies in your house that will get below freezing if the general temperature is set too low.If there are any water pipes in that area........

I have a Heat Pump. Bought the house brand new and never went anywhere, the first Heat Pump lasted 10 years. The first pump went out the week before we left for the first winter. We've had this pump for 14 years and we go away for 4 or 5 months at a time and we leave it on 54 degrees while away.

Ours is never set below 60F. (high efficiency natural gas furnace)

What temperature do you leave your home at | Good Sam Community

ramsaymike
Explorer
Jan 17, 2020
We are going to be a bit of an outlier here but this is what we have done for several years...
- 1600 sf bungalow in Peterborough Ontario area, well insulated and sealed (R2000 construction)
- House is winterized - water off, all pipes blown out and drains protected (just in case...)
- Thermostat (wifi) set at no more that 5C (41F)
- Heat is provided by 2 ton heat pump with 15kw resistance heater.
- House monitored remotely by camera - furnace performance and temperature/humidity recorded top to bottom
- Never any issues (min temp recorded was 3.5C)
- Heating Cost <$100 for 5.5 months

For what it is worth....
zcookiemonstar
Explorer
Jan 17, 2020
If you want your furnace to run longer to dry everything in the system out why not use a pogramable thermostat? You can set the temp several degrees warmer for one hour aday every day or just a couple days a week. A WiFi unit would work too but then you have to pay for internet service while your gone.
obgraham
Explorer
Jan 16, 2020
Mine's in a relatively dry area. Set it to 55, with a web connected Honeywell thermostat and a camera looking at the front door.

Snowed there today. Too bad!
wilber1
Explorer
Jan 16, 2020
16C or 61F. Hi efficiency natural gas. Nest thermostat, can check and see what it is doing each day online. Also have two 70% efficient gas fireplaces with thermostats set to 13C or 55F just in case the furnace quits.
babock
Explorer
Jan 12, 2020
DustyR wrote:
The four years I spent south I always set the thermostat at 60*, because of wanting good heat on the pluming. The most concern is in the case of severe weather, you need a friend or electronic device to be sure the heating system is functioning.
That's why you get an internet thermostat.
DustyR
Explorer
Jan 06, 2020
The four years I spent south I always set the thermostat at 60*, because of wanting good heat on the pluming. The most concern is in the case of severe weather, you need a friend or electronic device to be sure the heating system is functioning.
bucky
Explorer II
Jan 05, 2020
Without a automatic propane whole house generator with a huge tank all of the above except the Minnesota crowd are just sharing ideas. Most will have family or friends nearby that can check but they will be helpless in an extended outage.
Ice storms can be brutal on the electric grid.
Whiskey_River
Explorer
Oct 23, 2019
Jumping back in...
After 46 posts it appears you should set the thermostat at your sticks & bricks at what you want.
I do 45 as does sidecar & turn off the water & open cabinet doors.
Some have said low temps may cause structural damage. Not sure what that would be as all outside walls & root trusses including the bottom cord (ceiling) are all at outside ambient temp or very close to it, no heat there.
I heard years ago that plastered walls should not be left in the cold for any length of time. Don't know if that's true or not. With the introduction of dry wall 50 or 60 years ago, plastered walls have mostly gone with the dodo bird.
My thought is the interior heat is for the comfort of the occupants of the house. The couch just sits there & doesn't care if its 45 or 55 degree's. The carpet just lays there & does not care if its 55 or 65 degree's.
And I don't know what some folks pay for electric or gas, but in a Pittsburgh winter its a lot more than penny's between 45 degrees & 65 degrees. I'm not against using my share of the "carbon footprint" either, when I'm home in winter, its 70 degrees...…….
BarneyS
Explorer III
Oct 22, 2019
I always set ours at 56 degrees. I figured that at that temp the furnace would come on enough to keep the humidity where it should be but not come on enough to break the bank. Worked fine for all the 19 years that we snowbirded.
Barney
almcc
Explorer
Oct 21, 2019
After reading the link above from the contractors it brings up some additional thoughts and comments about the condensation that's causing the heat exchanger damage.

I assume that the condensation occurs on the warm air side of the exchanger, if so whether your furnace gets damaged may depend on the climate conditions where you live. Here in the cold dry north the inside humidity level is so low in the house during the winter that the wood cabinets shrink due to moisture loss. I don't think that running the house temp lower than 60F will damage our furnace. Maybe a heating contractor/tekkie can comment.