Great Mills Heating & A/C, Inc.

Great Mills Heating & A/C, Inc. Family owned and operated Heating & Cooling company since 1972. We provide HVAC services to part of Calvert and Charles county, along with all of St.

Mary’s County. Great Mills Heating & A/C, Inc provides residential and commercial air conditioning, heating, furnaces, water heaters, mini splits, indoor air quality, and geothermal sales and service to St. Mary's County, MD, and surrounding areas.

09/02/2026

Some spaces in the home never seem to match the rest when it comes to temperature control. Mini split systems offer zoned comfort, letting each room stay just the way your family prefers it. It’s a flexible way to improve comfort without overworking your main system.

Get in touch to explore a setup that fits your home’s needs. Visit https://www.greatmillshtgac.com/s/K3J5W7t

08/26/2026

When Maryland's humidity and seasonal weather put your HVAC system to the test, experience matters. Great Mills Heating & Air Conditioning provides customized solutions designed to keep your home efficient and comfortable in every season.

Discover how our NATE-certified technicians handle even the toughest heating and cooling challenges. Visit https://www.greatmillshtgac.com/s/d4p7c0A

08/21/2026

: How often should I change my air filters?

Air filters are a small part of your HVAC system, but they make a big difference in performance and air quality. 🌬️ Keeping them clean helps your system run smoothly and efficiently.

General guidelines:
🗓️ Every 1–3 months for most standard homes
🐾 More often if you have pets or allergies
🏠 More frequently during heavy HVAC use seasons
🧹 Check monthly to avoid buildup

A clean filter helps your system breathe easier and work more efficiently. Visit https://www.greatmillshtgac.com/s/y2S0e1i

If your AC unit or furnace is getting older, you've probably been putting off an entire replacement for a while now.May...
08/20/2026

If your AC unit or furnace is getting older, you've probably been putting off an entire replacement for a while now.

Maybe you heard the federal tax credit could knock $2,000 off a new heat pump. Then you heard it went away.

So now you're stuck wondering if you missed your window. That worry is real, and you're not alone in feeling it.

Here in Southern Maryland, summers turn humid and winters bite hard. An aging HVAC system always picks the worst moment to quit.

The good news is simple. The federal credit is gone, but Maryland rebates are still very much alive.

https://www.greatmillshtgac.com/blog/2026/august/maryland-hvac-rebates-in-2026-the-federal-credit/

Upgrading your AC isn’t just about staying cool—it’s about making a smarter long-term investment. ❄️🏠A properly installe...
08/17/2026

Upgrading your AC isn’t just about staying cool—it’s about making a smarter long-term investment. ❄️🏠

A properly installed system can improve comfort, lower energy use, and reduce breakdowns during the hottest days.

Here’s what we focus on during installation:
🌱 Energy-efficient systems with eco-friendly refrigerants
🌡️ Equipment matched to your home’s exact cooling needs
📊 Solutions designed for local climate performance
💳 Flexible financing and payment plan options

We help you think beyond “right now” so your new system works for years—not just seasons. Visit https://www.greatmillshtgac.com/s/T1s688D

If you are considering an HVAC repair or new system installation for your Maryland home, here is a recent customer's exp...
08/14/2026

If you are considering an HVAC repair or new system installation for your Maryland home, here is a recent customer's experience:

“I must say, they are an exceptionally skilled group. They completed both the removal and installation swiftly and efficiently. Their work was tidy, and they approached every task thoughtfully, transforming my initial dread into a sense of relief.”

08/11/2026

We truly appreciate you trusting us with both your water heater and HVAC system, Kathryn. It means a lot to hear you’ve had a strong experience more than once! Visit https://www.greatmillshtgac.com/s/n6l189y

08/06/2026

At Great Mills Heating & Air Conditioning, we combine decades of experience with a commitment to quality, precision, and customer care. Fully licensed and insured, our team makes it easy to get free estimates and stress-free HVAC solutions.

Learn more about why Southern Maryland homeowners continue to trust our service. Visit https://www.greatmillshtgac.com/s/06C2j0b

08/03/2026

If the air inside feels heavy or uneven, your HVAC system may be circulating more than just cool air. Dust buildup, humidity imbalance, and poor filtration can all affect how comfortable your home feels day to day. Improving air quality helps every room feel more consistent and refreshing.

Contact our team to help improve the air you breathe at home. Visit https://www.greatmillshtgac.com/s/L4l4e8U

Address

21305 Great Mills Road
Lexington Park, MD
20653

Opening Hours

Monday 7:30am - 4:30pm
Tuesday 7:30am - 4:30pm
Wednesday 7:30am - 4:30pm
Thursday 7:30am - 4:30pm
Friday 7:30am - 4:30pm

Telephone

+13019940522

Website

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