I live in an apartment/condominium renting from an owner directly. We are directly responsible for any maintenance or repair work. Our heating unit is blowing out cold air past two days. Please advise on what could be possibly going wrong and how to resolve the problem without hiring someone.

First you need to find out and tell us what kind of heat you have, Heatpump? Electric? Gas? A name brand and model number could help also. Any and all information would help