Which is more energy efficient? A programmable thermostat OR leaving furnace set at certain temp?

I have heard both it is more cost effective to leave your thermostat at a constant temp and it is more cost effective to have it vary depending if someone is home.

One more factor is what the temp is outside. Here in New England, it can get quite cold. So if the temp outside is lets say 12 degrees, from what I am told it is more cost effective to leave it on a constant setting. In the spring and fall when the daytime temps are higher, it is more cost effective to adjust your thermostat. It has to do with what it would take to bring the temp in your home back up to the temp you prefer. It is more difficult to do that if the outside temp is really cold. Especially if the wind is blowing.

I hope this adds to your information about programmable thermostats.

a programmable thermostat will give you better energy efficiency. Yes, perhaps there is a little more energy used to turn it on and off, but if you are off to work for the day, having that thermostat raise the temperature 2-5 C will save much more than is used to start it up.

Here is a good schedule for a programmable thermostat:

8am temp goes up 5 degrees

5pm temp comes down to your comfort level

12am temp goes up a few degrees

6:30am temp goes down

Good answers above, but the short answer is that if nobody is home during the day, a programmable thermostat that keeps the furnace from running during the day is better, but if someone is there all day it is better to set it at the lowest comfortable temperature and leave it there.

Really depends on how you program the thermostat, but yes sometimes it is better to in fact leave at at a certain temperature.

Someone can leave their thermostat at like 22C in the winter. Another person can program theirs to be at say 20C in the morning when everyone is gone and on again at 24C. Average is 22C.

It all depends on how you use your thermostat. Big changes on not good.

What I do with mine is start off with 20C in the morning then gradually during the day it will reach 22C until 11 o'clock at which point it goes back down to 20C.

Depends on your climate. But if you lower your thermostat at night and during the day when you are away you have to save on energy. It will only run for a little more time than "normal" to get it up to temperature. If you are home all day it is a moot point, because you won't tolerate so low a temperature. (during the winter for example)

So your keeping it at like 55 degrees during the day and at night, you have to save oil that way. It is like 18 hours of the 24.

Mine is set at 64 all the time. On weekends when I am home I set it back to 60. So far its been relatively warm here in VA. My kids like to sit under blankets when watching tv or surfing internet, We also wear socks and long sleeves around the house if necessary.