24/7 HVAC Repair & Service in
Southern Maryland


When your heating or air conditioning system breaks down, you need a trusted local company that can respond fast. Tri-County Aire has been the HVAC repair and service company Southern Maryland homeowners and businesses rely on since 1987. Our NATE-certified technicians diagnose and repair all makes and models — and we're available 24 hours a day, 7 days a week for emergencies.


Call us anytime: 800-890-5123


Same-Day & Emergency HVAC Service

We know a broken AC in the middle of a Maryland summer — or a failed furnace in January — can't wait. That's why Tri-County Aire offers same-day service and 24/7 emergency dispatch across Calvert, Charles, and St. Mary's Counties. When you call, a real person answers. We'll get a technician to your door as quickly as possible.


What We Repair

Our factory-trained technicians service and repair all major residential and light commercial HVAC systems, including:

  • Central air conditioners — all makes and models
  • Gas and oil furnaces
  • Heat pumps (including geothermal systems)
  • Ductless mini-split systems
  • Indoor air quality equipment — air handlers, humidifiers, UV air purifiers
  • Thermostats and controls


We work on equipment from Trane, Carrier, Lennox, Rheem, Mitsubishi, WaterFurnace, and most other major brands.


Common HVAC Problems We Fix

Not sure if what you're experiencing warrants a service call? These are the issues our technicians handle most often in Southern Maryland homes:


  • AC not cooling or blowing warm air
  • Furnace not heating or cycling on and off
  • Unusual noises — banging, rattling, squealing, or grinding
  • System running constantly but not reaching set temperature
  • High energy bills without a change in usage
  • Frozen evaporator coil
  • Refrigerant leaks
  • Thermostat not responding
  • Uneven heating or cooling room to room


If your system is doing any of these things, don't wait — small problems become expensive repairs when ignored.


Why Southern Maryland Chooses Tri-County Aire for HVAC Repair

38+ years of experience. We've been servicing Southern Maryland HVAC systems since 1987. We know the homes, the climate, and the equipment common to this region.


NATE-certified technicians. Every technician on our team is factory-trained and NATE-certified — the highest industry credential for HVAC service professionals.


30-vehicle fleet with GPS dispatch. Our dispatchers track every service vehicle in real time, so we can get the closest available tech to your home fast.


Honest, upfront pricing. We diagnose the problem, explain your options, and give you a clear price before any work begins. No surprises.


BBB-accredited business. We've maintained our Better Business Bureau accreditation for decades because we stand behind our work.


Financing available. If your repair leads to a larger system need, we offer financing options — including 0% APR plans — to help you manage the cost.

FAQ: HVAC Repair in Southern Maryland

  • How quickly can Tri-County Aire respond to an HVAC repair call?

    For emergency HVAC repairs in Southern Maryland, Tri-County Aire is available 24 hours a day, 7 days a week. During regular business hours — Monday through Friday, 7:30 a.m. to 4:00 p.m. — our team can often schedule same-day service. After hours, our answering service connects you directly to an on-call technician.

  • Do you repair all brands of HVAC equipment?

    Yes. Tri-County Aire's technicians are trained to repair all major HVAC brands, including Trane, Carrier, Lennox, Rheem, Mitsubishi, and WaterFurnace. Whether we installed your system or not, we can service it.

  • How much does HVAC repair cost in Southern Maryland?

    HVAC repair costs vary depending on the problem, the part needed, and the equipment type. Minor repairs may run $150–$400; more complex issues involving refrigerant or major components can cost more. Tri-County Aire provides an honest diagnosis and a clear estimate before any work begins. We never start work without your approval.

  • Should I repair or replace my HVAC system?

    A good rule of thumb is the "5,000 rule": multiply the system's age in years by the estimated repair cost. If that number exceeds $5,000, replacement is often the smarter investment. Our technicians will walk you through the options honestly — we're not going to push a new system when a repair makes sense.

  • Is it worth getting an HVAC maintenance plan to avoid repairs?

    Yes. Regular maintenance by a certified technician reduces the likelihood of unexpected breakdowns, extends equipment life, and keeps your warranty valid. Ask us about Tri-County Aire's maintenance agreements — they're designed to keep your system running right all year long.

  • Do you offer financing for HVAC repairs or replacement?

    Yes. If your repair leads to a system replacement, Tri-County Aire offers financing options, including 0% APR plans for qualified customers. Ask our team about current offers when you call.

Service Areas

Tri-County Aire provides HVAC repair and service throughout Southern Maryland and into northern Virginia, including:

  • Calvert County: Prince Frederick, Dunkirk, Chesapeake Beach, North Beach, St. Leonard, Huntingtown
  • Charles County: La Plata, Waldorf, White Plains, Indian Head, Bryans Road
  • St. Mary's County: Leonardtown, Lexington Park, California, Great Mills, Hollywood
  • King George County, VA


Schedule HVAC Repair Service Today

Don't let a malfunctioning heating or cooling system disrupt your comfort. Tri-County Aire's certified technicians are ready to diagnose and fix the problem — fast.

📞 Call 800-890-5123 — available 24/7 for emergencies

🖥️ Request Service Online — our team will respond promptly.