St. Marys and Calvert County Maryland HVAC Services   ♦   We Make Your Air Flow!

Southern Maryland
St. Marys and Calvert County Maryland HVAC Services
We Make Your Air Flow!

Southern MD air conditioning repairs

Great Mills Heating and Air Conditioning, Inc. is a locally owned and operated full service residential, business and commercial heating and air conditioning contractor.

We have been repairing, servicing, and installing Carrier equipment and others in Southern Maryland in St. Mary's County and Southern Calvert County (Prince Frederick & South) since 1972. Great Mills specializes in the repair, maintenance and replacement of existing residential and commercial comfort control systems.

Some of our many HVAC services include: heating repair in Southern Maryland, furnace repair in Southern Maryland, oil furnace repair in Southern Maryland and gas furnace repair in Southern Maryland. We are a heating contractor in Southern Maryland, oil furnace contractor in Southern Maryland, gas furnace contractor in Southern MD.

Southern MD Heat Pumps, Heating & Cooling System Installation Services & System Types:

  • Direct Heating & Cooling System Replacement
  • Heating & Cooling System Service & Repair
  • Oil Tank Installations
  • Oil Tank Service & Repair
  • Oil Furnaces
  • Oil Furnace Service & Repair
  • Gas Furnaces
  • Gas Furnace Service & Repair
  • Propane Furnaces
  • Propane Furnace Service & Repair

  • Radiant Heating
  • Radiant Heating Service & Repair
  • Heat Pumps
  • Heat Pump Service & Repair
  • Air Conditioning
  • Air Conditioning System Service & Repair
  • Heating & Cooling Zoning
  • Heating & Cooling System Service Agreements
  • Heating & Cooling System Service & Repair

St Marys HVAC

Google Reviews

J. Petrosillo
These guys were great! Honest and to the point. They didn’t try to pressure you into buying things like the other guys.

M. Periman
Fast, professional, kind.

Mark W
Excellent experience! Furnace not working and 20 degrees outside... Great Mills H&AC answered my call at 7:15 am. Setup the appointment for 8:00 am. Arrived at 7:50 am. 2.5 hours later problem fixed and heat back on. Technicians did an EXCELLENT job. Very professional. Total bill... Less than $200 including parts and labor for two technicians! AWESOME!!

Bree Daisy
I called GM HVAC due to smelling gas the second time we ran our heat for the season and they had a technician out to my home within 20 minutes. He completed the task within an hour and sealed our leak very well. The tech was friendly, polite, and respectful. Highly recommend!

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