Kenneth wrote:
On Fri, 30 Nov 2007 22:21:13 -0500, Jim Behning
wrote:

Now that has a few good answers. I would not have thought about the
freezing closed loops.
....
Any responsibly designed system protects against such
freezing...

....

My thinking precisely. The response basically is a bunch of
weasel-words. The upshot basically is if the aux heat issue is taken
care of properly and one doesn't mind the recovery time, setback will
save. For a reasonable source capacity, our experience was that while
the outlet temperatures aren't equivalent to gas, they're sufficiently
high the air feels "warm enough" circulating as opposed to the and as
compared to air-air heat pump that felt cool...

If there's freeze-up w/ a few degrees setback so the unit runs a little
less at night, there's going to be freeze up on other days as well...

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