I'm also a heat pump owner, so I can understand the high bill frustration ($700+ for a single family home, neighbors wasn't much less and they have new windows).

If you're switching over to emergency "supplemental" heat, you are effectively making that your ONLY heat source, which is very costly. I suggest just letting the heat pump system (specifically the thermostat) use supplemental heat on an as-needed basis to assist during the colder days. If you don't think your thermostat is "smart" when it comes to managing back-up heat, it might be worth looking into one that does (I use a Honeywell VisionPRO 8000), which determines when the back-up heat is necessary and cycles it rather than leaving it on. You don't want to stop the heat pump altogether because it is still more efficient than the heat strips even down to very low temperatures. But the heat strips will help the temperature rise during the colder days.

thanks for your help.

here's what i'm confused about. Our thermostat has a manual switch for supplemental heat. It also has a red indicator light that says supplemental heat and seems to come on when it is quite cold.

i guess i'm not sure if that light is telling us that it's cold enough we should switch it over to supplemental for a period of time or is it saying that it is automatically using it as needed?

everything that you've said makes sense, i just want to make sure i understand in relation to my pump.

I don't know of any thermostat that has a light alerting you of the need to use supplemental heat, but I do know thermostats will indicate when they are using supplemental heat, so I believe this is the case. Mine will say "Aux Heat On."

oh ok. i think you're right. thanks for your help!!

Your confusion is largely over the terms "supplemental" heat and "emergency" heat. Both refer to the electric heat strips. Supplemental means the heat pump (compressor) and heat strips run at the same time. The heat strips supplement the output of the heat pump. Your indoor thermostat automatically triggers the strips when needed if it senses that the heat pump alone isn't able to maintain the desired indoor temperature. Emergency (the manual switch on your thermostat) shuts off the compressor and runs only the heat strips ... intended for use such as if the compressor fails and there's no source of heat except the strips. You can also use it in other situations such as if the weather is wet/snowy, causing the outdoor coil to ice-up quickly and need frequent defrosting.

The indicator light on your thermostat simply gives a visual indication that the heat strips are active ... perhaps as a reminder to switch it back to normal after the "emergency" is over.

thank you dadoes! that is exactly what i wasn't understanding. seems so simple now:)

thanks to you both!