pyotr filipivich wrote:

Let the Record show that "Pete C." on or about
Thu, 29 Oct 2009 13:30:44 -0500 did write/type or cause to appear in
rec.crafts.metalworking the following:

That isn't a "pair of heating systems", nearly all heat pumps include
backup heat strips for times when the heat pump is not able to produce
enough heat such as very cold weather / high demand.


In the case you've described, you aren't dealing just with the
thermodynamics of the situation. You're also adding the complexity of
multiple heat sources that operate under different circumstances.

That complexity exists everywhere and that was my point - you have to do
the actual analysis of the home in question to get the correct answer -
you can't rely on blanket statements / myths.

An additional complication is occupancy, since for folks who are retired
or work from home, or a stay at home spouse, you loose half or more of
your theoretical savings period with the occupants not being away during
the day.

OTOH., we can turn the heat down in the rest of the house, warm
just the office, and double up the blankets at night. Just don't let
the pipes freeze. B-) (that means no coffee.)

Well, ideally you should be zoning and not heating long unoccupied rooms
beyond maintenance level anyway. Certainly I have the dampers mostly
closed on my spare bedroom and dining room pretty much all the time,
only opening them on the rare occasion those rooms will be occupied.