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

St Mary's County Heat Pumps, Heating & Cooling System Installation & Service Repair


Great Mills Heating & Air Conditioning Contractors Inc is a locally owned and operated full service residential, business and commercial heating and air conditioning contractor. They have been repairing, servicing, and installing HVAC equipment and others in Southern MD in St. Mary's County since 1972. Great Mills specializes in the repair, maintenance and replacement of existing residential and commercial comfort control systems as well as oil tank installations, oil furnaces, gas furnaces, propane furnaces and radiant heating.

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


Services and System Types:


  • Leonardtown Direct Heating & Cooling System Replacement
  • St. Mary's County Heating & Cooling System Service & Repair
  • Budds Creek Oil Tank Installations
  • St. Marys Oil Tank Service & Repair
  • Mechanicsville Oil Furnaces
  • Hollywood Oil furnace Service & Repair
  • Charlotte Hall Gas Furnaces
  • Great Mills Gas Furnace Service & Repair
  • Lexington Park Propane Furnaces
  • Wildewood Propane Furnace Service & Repair


  • California Radiant Heating
  • Buds Creek Radiant Heating Service & Repair
  • Leonardtown Heat Pumps
  • St. Marys City Heat Pump Service & Repair
  • Great Mills Air Conditioning
  • Charlotte Hall Air Conditioning System Service & Repair
  • Hollywood Heating & Cooling Zoning
  • St. Marys County Heating & Cooling System Service Agreements
  • Mechanicsville Heating & Cooling System Service & Repair
St Marys Carrier Heat Pump St Marys HVAC Installation

Great Mills is your St. Marys County heat pump repair, heat pump maintenance and heat pump replacement contractor in existing homes and commercial comfort control systems in the following areas: Budds Creek, Mechanicsville, Charlotte Hall, Leonardtown, Lexington Park, California, Wildewood, Great Mills, Hollywood, St Marys City and all of St. Mary's County, Maryland.


Financing Options


Great Mills Heating and Air offers various financing options:


Call the office for other options 301-866-1433.


Call Us or Email Us


for Info on SMECO Rebates and Carrier Spring Rebates On complete HVAC system installations!




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