RMUH wrote:
One of my customers asked me whether she should believe a furnace
installer who told her it is more efficient to leave the heat on all
night than to turn it off.

Clearly, the heat loss from the building is less if the temperature
inside is lower, as it would be when the heat is off.

However I have heard it stated so often and by people who ought(!) to
know, that I wonder if there is some reason not to turn the heat off.
Anybody really know exactly why this is or is not true?

Thanks

It it is not a heat pump then it is a good bet that turning it down or
off will reduce total usage. If it is a heat pump, it may increase
electricity usage reduce it or make no difference depending on many
variables.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math