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

heating ac repairs

Great Mills Heating and Air Conditioning, Inc. is a Southern MD, locally owned, HVAC contractor specializing in the repair, installation and servicing of Carrier home, residential, commercial, heat pumps, gas furnaces, propane furnaces, oil furnaces, water heaters, humidifiers and radiant heating. We also repair any make or model of heating and cooling comfort control system, heat pump or furnace.

About Us

Great Mills Heating and Air Conditioning was founded in June of 1972 by Charles E. Aud, Sr. We now have three owners: Charles E. Aud, Sr. (President), Kirk E. Kuginskie (Vice President) and Lisa M. Aud (Secretary/Treasurer). We are a Factory Authorized Carrier Dealer. Since 1972, we have been installing and servicing Carrier heating and cooling equipment, and improving indoor air quality in the St. Mary’s County and Southern Calvert County, Southern Maryland areas.

Great Mills Air Conditioning

Phone: 301-994-0522 

Emergency Service after 4:30pm:


Financing for Heating & Cooling Heat Pump Systems Great Mills Heating and Air offers financing and also accepts all credit cards.

Free Estimate

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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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All credit cards