My Carrier heat pump is not working properly. The air flow coming out the vents is drastically lower than it normally is. The maximum room temperature achivable is 65 degrees when the outside temperature is 20 degrees even when the auxiliary heat is on and with constant running. The air filters are clean. The unit is less than 2 years old and was installed in a new house.

At 2 years old, it should be under warranty,since you are sure the filter is clean,could be a problem with the blower motor,, at 20 degrees the heat pump won`t be of much help, so ,yes the aux heat should be doing a much better job, is the aux heat electric or gas furnace? This would be a need to know in order to help you,, is the aux/furnace also 2 years old?

The auxiliary heat is electric. The auxiliary heat is included and is part of the Carrier heat pump.

I would check the reversing valve. You can tap on it lightly with a scewdriver handle, maybe the slide is stuck. Another problem is to check the connection at the reversing valve. Disconnet it then reconnect it you should hear a distinct sound. Another thing to check is the thermostat and make sure it is hooked up properly. I believe the blue wire is for ememergency haet.

Were filter neglected for two years? If so, cond/evap coil could be plugged, not likely. If temp outside is low enough, compressor won't even kick on (on some heat pump units), so you are left strictly with electric backup. But your problem sounds like an airflow problem. Are you sure airflow has decreased, or just the temp of air coming out.

Post is over a month old,, I would hope its fixed by now,:)

Good call, I didn't even look at post date. Hope they are warm and fuzzy. Would have been nice for them to let the nice folks here know how it turned out. Oh well, not the first time and won't be the last.