I replaced our A-C/propane-heat roof-top unit (it died) with a heat pump about two years ago. Our goal was to move to something sustainable, and we have solar panels for electricity, but not enough for the heatpump. Even if a lot of the electricity provided by Edison is produced with a carbon footprint now, that might not be the case in the future.

I'm not an engineer, but I read somewhere that the colder it is outside the less advantage there is to a heat pump. And our experience is that when it's close to freezing outside, the heat pump struggles and is quite noisy, the unit spends a lot of time in defrost-mode, etc.

Our thinking is, perhaps heat pumps are more appropriate for a more temperate climate than where we live (San Joaquin Valley in Ca., elevation about 800 ft.). However, we have it now. So, how do we get the best from it?

For example, if it's 40F. outside at 10pm and it will be 30F at the 6a following, maybe we ought to crank it up at night so the house will stay warmer through the night. Or, perhaps we should be using some plain-old resistance-electric heaters in smaller areas of the house when it's near freezing outside.

If anyone can direct me to some technical data on this matter, I'd really appreciate it. Somehow I have not been successful in getting the information from the manufacturer of our unit. But this kind of information must be available in this modern web age.. I just don't know where to look.

Sincerely,

Ken Elias
Three Rivers, CA