Is the HVAC contractor licensed to do the repair? Is the contractor certified by either the manufacturer or NATE? Is the contractor sufficiently insured?

Get a firm bid for the work prior to hiring the contractor. You do not want any surprises once the work has been done. Having a signed work order or contract is the best policy.

Depending on your current unit, the best HVAC repair contractor may be one that is factory trained for that unit. Are the repairs needed immediately? If so, you may need to make the best choice from the list of repair contractors that are available right away.

Is the HVAC contractor who installed the unit originally still in business? If so, that contractor may be your best choice for a repair. Is your unit still in warranty? There are often rules concerning warranty work that need to be followed. Check the paperwork and be sure you follow those rules.

Will the HVAC contractor you are considering back their work? Ask for references from past customers. Call each one and ask especially if they had to call in the contractor more than once to get the work properly done.