[whitedavidp]

Originally Posted by whitedavidp

You are correct. It is a heat pump.

Thanks once again for your response. I found some info on the internet here <en.allexperts.com/q/Heating-Air-Conditioning-696/2008/2/Heat-pump-thermostat-control.htm>
and here <en.allexperts.com/q/Heating-Air-Conditioning-696/2008/2/Heat-pump-thermostat-control.htm>
that made me start checking things more carefully.

When this cold spell hit, I raised the temperatures on my thermostat schedules. I have never done this before. Under the previous schedule, I had simply raised the temp manually on the thermostat to what I wanted when needed. Thinking back, this is when I typically saw the aux heat indicator show on the thermostat.

So I just manually raised the temperature from its current setting by a couple degrees and indeed the thermostat does show the aux heat indicator. For this reason, I am thinking that the aux heater does, in fact, work.

However, I am not sure about if it is working during the defrost cycle of the heat pump. I only found out recently that there was such a thing. I may never have noticed it before because it has never been this cold this long since I have been in this house with the heat pump. Maybe the heat pump only has to go through a defrost cycle when it is very cold. Or maybe it does it frequently but I have only noticed it now because the air being used right now is so very cold.

Do I have to call in a pro to see it the thing is properly set/wired so that the aux heat comes on during the defrost cycle? Or is there some way I can check that?

Thanks and happy holidays to all!