BillC wrote:
"Noon-Air" wrote in message
news

"BillC" wrote in message
link.net...
HI,

I set the thermostat timer for a minimum overnight temperature of 45
degrees, to heat to 70 at 6:30 AM. Effectively, this leaves the furnace
turned off overnight. I figure that saves wear on the furnace / fan and
saves fuel costs overnight.
However, I heard on a radio program that thermostat timers should
only have a max differential of about 8 or 10 degrees.

Anybody know what the best settings are?

use 10 degree setbacks for best efficiency and least problems

OK, but why? Does 15 or 20 plus degrees of heat differential mean the
furnace gets too hot when running to close the gap, or what?

If you have a heat pump, 8-10 is likely to produce the best savings in
most areas. A larger setback can cause more time in supplemental heat mode
where it is less efficient.

For resistance heat, every degree of additional setback will save money,
but too much could cause damage to pipes and furniture. With the addition
of a grand piano my nightly setback has been reduced.

For gas heat, like I have, you still can have some reduction in
efficiency, but for the most part the problem is the secondary effects. I
would stick to 15 or less.


--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math