John, in MN responds:

And maybe I'm getting screwed. Hard to tell. I was told that when the air is
much below freezing, heat pump efficiency drops dramatically. I'll have to
dig
out some information on the thing, as we seldom get down to 10 degrees here,
so
a setting of, say, 20 or so if it is reasonably efficient, might prove a
money
saver when the guy in the rolling propane bottle pops down the drive.

Charlie, I did a temp plot last night of the heat pump. It started to
lose ground at about 10 deg. About 30 minutes later it switched over
to the propane furnace. We had 9 below last night. At 20 degrees
your pump should be happy. The manual for mine specs down to 0 for
outside operating temp. Also the measured power on ours is about
2200 watts. So it only costs about 7 cents per hour of run time.

Eeeeeeeeeee! Nine below? Just think, I moved down here as a geographic cure for
a marriage that had failed, and escaped that kind of weather, too. It did hit
five below here...IIRC, in 1985.

Thanks. I'll have the guy who's coming check the settings--and show me how to
recheck and reset--and I'll also make sure he gives the whole shooting match a
good going over. It has been in just over three years, so I don't foresee big
problems for another four or five.

I don't even know if we GOT a manual with this thing. I'll check around the
washing machine area (basement appliance manual files).

Charlie Self
"It is when power is wedded to chronic fear that it becomes formidable." Eric
Hoffer