"---MIKE---" wrote in message
...
I have a small log home. The logs are efficient insulators plus they
act as a heat sink. My heat is baseboard hot water and I have two
thermostats controlled by a homemade switcher. The "day" thermostat is
set to 65° and the night one is 57°. This does save some oil. My
question is about daytime if I leave the house. Does it make sense to
go on the lower setting for just four hours? It would use less oil
during that time but then it would use more to "catch up" when I get
home. What would be the minimum number of hours that would give the
best savings on oil?



http://www.mge.com/home/saving/thermostat.htm
http://www.energy.iastate.edu/news/p...backtherm.html
A common misconception associated with programmable thermostats is that a
furnace works harder than normal to warm the home back to a comfortable
temperature after the thermostat has been set back, resulting in little or
no savings. Years of research and numerous studies have shown that the fuel
required to reheat a home is roughly equal to the fuel saved as the home
drops to the lower temperature. This will result in fuel savings between the
times the temperature stabilizes at the lower level and the next time heat
is needed. The longer the house remains at the lower temperature, the more
energy saved.