Before you hire
In Maryland, look up the company with the State Board of HVACR Contractors, and for home improvement contracts the Maryland Home Improvement Commission. In Virginia, HVAC tradesmen must hold state certification from the Department of Professional and Occupational Regulation, and contracting businesses are licensed by its Board for Contractors. In Washington DC, the Office of the Attorney General advises that refrigeration and air conditioning mechanics need a trade license and that most home improvement work needs a District permit. This directory does not verify licenses. Ask for the license number and look it up before you sign, and ask for a Manual J load calculation before anyone sizes a heat pump.