[maxerickson]

How is the insulation in the house? Poor insulation and an undersized system will be a bad experience regardless of the heat source.

[baggy_trough]

It wasn't a bad experience before, but now it is, because of: new heat pump

[maxerickson]

Well what capacity does each system have?

That they came back and added resistive heating suggests your contractor may not have been too worried about sizing the system correctly in the first place.

[baggy_trough]

Seems like it's harder to correctly size a heat pump system, perhaps because it costs more if right sized, if it's even possible to right size it at all.