There could be a couple of reasons why your heat pump is not putting out hot air. Two of the most common reasons are that your heat pump is low on refrigerant liquid and needs to be refilled, or that a part is out of place or broken and is in need of repair. No matter what the reason is for your heat pump not working, give the HVAC technicians a call at Triple Service Inc and they will give you a professional, up-front repair estimate.