Heat Pumps and Electric Heating - auxillary heat question

We just had a new heat pump/aux heat/ac unit put in. It is a 3.5 ton with a 4 ton blower. It is in the low 30's last night & this morning. We put it over to Aux. heat & the air coming out feels cool unlike our last unit that would blow so much warmer when on the aux heat. I put a little thermostat on one of the vents & it was blowing out 79 degree air. The thermostat was on 66 at 8:20am and it is now 9:12 am & the temp has only come up one degree. What temp should the Aux. heat unit be putting out? It feels more like the heatpump only is putting out air, but I went outside and it is not running which tells me only my aux. heat is going (which that is what I have it on). Can anyone help me?

Aux Heat is additional heat for the heat pump.
Let the heatpump run and the thermostat will control Aux heat will come on when needed.

The Aux/EM emergency switch is only when your compressor is not working and you need some heat from your electric heat strips.

The reason why your new heater in Aux/EM heat is not heating as much as your old one may be do to a smaller kw heat strip.

Not sure what you have there just post the brand and model numbers.That should indicate the Heat strip sizing. Sometimes a installer gets in a hurry and will miss the sequencer wiring and only have part of the 15KW heat coils pulling in. Some units can be staged where only 5 or 10 KW comes in as aux with the heat pump but all 15KW comes in when the tstat is set to Emer heat etc. just according to what you have there. Probably just need to get the installer back out to check it.

My heat pump model is RHEEM PQL -JEZ 15 SEER
Comfort Control System

Unit in basement is RHLLHM4821JA

Thanks for the help!!

Hmmm a Rheem then huh. Field installed aux heat coils then, it should show on your paperwork what they purchased and installed. 3.5 ton should have 15kw if they installed something less have them change them out. I like to stage the Rheems using 10kw as aux to kick in with the heat pump as supplemental then have all 15kw kick in on emergency heat setting (you will need a tstat that is capable of giving you that control). A nice Honeywell 8000 with the outdoor sensor gives you verything you need including heat pump lockout so you have ultimate control over your system. Rheem makes good equipment, once this system is set up correctly you should be pleased I am a bit surprised that you had to got to emergency heat at 30f there may be a problem with the installation of this unit.................

I agree, you shouldn't have to switch over to Emg heat when it's that mild out.

What do you have for t-stat? (Make/model) As FM pointed out, a good t-stat will control this all for you.