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Air Conditioning Service Experts in Gaithersburg

When the seasons being to change & the first glimpse of spring air hits Gaithersburg, turn to the experts at Mannix Heating & Cooling for your air conditioning needs. It is imperative to perform pre-season maintenance on your air conditioning system before the warm weather hits. Professional maintenance is needed for any make, model or year of air conditioning system. Annual AC maintenance will help cut down on untimely breakdowns & utility costs. Uninterrupted, cool air delivery is our goal to you for the entire summer season. For any air conditioning repair, service or installation call (703) 777-9211 to speak to one of Mannix Heating & Cooling’s HVAC experts.

Heating Repair & Furnace Installation in Gaithersburg, MD

Are you finding that your furnace is struggling to keep you warm at night? Are there any loud bangs or whistles coming from your heating system? Is your furnace constantly running? If you answered yes to any of these questions, it may be time to schedule heating repair service with Mannix Heating & Cooling. One of our highly trained technicians will come into your home & help diagnose the issue. We keep our service trucks stocked with many HVAC parts so we can get your heating system repaired in the same day. Sometimes our team of experts find that a heating system may be beyond repair. When that situation arises, Mannix Heating & Cooling offers a wide range of Carrier heating systems to best fit your heating need. Our heating installation technicians will advise on the best heating system for your home. Mannix Heating & Cooling also offers financing options with approved credit to help with your purchase. For heating, air conditioning or electrical needs, contact Mannix Heating & Cooling at (703) 777-9211!

Air Conditioning Installation, HVAC Service, AC Service, HVAC Repair & AC Repair Gaithersburg, MD, Chantilly, VA, Dulles, VA, Leesburg, VA, Potomac, MD & Rockville, MD

A/C Service Gaithersburg, MD | AC Service Chantilly, VA | Heating Repair Dulles, VA

Air Conditioner RepairAir Conditioning RepairAir Conditioner ServiceCentral Air RepairAir Conditioning Service ∴ Dulles, VA ∴ Gaithersburg, MD ∴ Leesburg, VA

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Customer Reviews

Shondra J ones

They were lifesavers!!! My furnace went out and after three days of dealing with the home warranty company and the unscrupulous vendor they sent to my home, I called Mannix. The service technician was friendly, efficient but most of all honest. He found the problem after twenty minutes, saving me thousands in unnecessary replacement costs. It is refreshing to know that honest people still exist.

Lynne Wilson

I contacted Mannix from a referral of a friend who has benefitted from the excellent service this company provides. I found out a couple I know in Vienna had their heat pump stop working a few months ago and needed to be replaced. I called up the Mannix office later in the day on Monday 11/30/20 and provided information needed. I had a proposal in my email the next morning 12-01-20. This will enable me to discuss with my friends how they wish to proceed with fair financing options available too. This is EXCELLENT customer service and I would like Mr. Mannix to know that Sarah is an amazing professional face for his company. I plan to become a customer of theirs by signing up for the annual maintenance plan which is very reasonable priced. Sincerely, Lynne Wilson

Philip Slingerland

Been a happy Mannix customer for a few years now, but recently had them replace our aging HVAC system. The whole process was very painless, from Eric helping us decide which system was right for our home, to the efficient and professional installation by Billy and Matt. I am very pleased with the new system and very impressed with the level of service, communication, and detailed information I received from everyone involved. Highly recommend!


Before dealing with Mannix I used two very well-known and “reputable” HVAC companies who did nothing but rip us off over the years. I was frustrated and found Mannix Heating & Cooling about 10 years ago. They installed a new HVAC system in my old home, and installed a water heater and various other items in my new home. They also have been doing yearly maintenance for years. Their employees are the most honest, reliable, and knowledgeable individuals in this industry. We recently had an issue with our HVAC system and they came out within a few hours on an emergency call. The technician was prompt, kind, professional, and very fair. He figured out what was wrong with our system quickly and remedied it immediately. Do not hesitate to call them if you need anything–you won’t regret it!

Wendy Collins

Mannix has always been professional from service calls to repairs and replacements. The technicians are always polite and knowledgeable. They consistently exceed our expectations.

Gary Hendricks

Mannix proved very responsive in fixing my A/C system. The tech, Erick, was very professional by taking the time showing and explaining to me the system problem prior to taking action replacing the coil. Ashleigh, customer service, was excellent in addressing and following through on concerns in order to achieve total customer satisfaction.

M. Reyzer

My 24-year-old heat pump finally decided to stop working. I sent a request for a replacement estimate late one night through the Mannix website and received a phone call early the very next morning to set up an appointment. Eric Holzworth stopped by my house the next day to go over my options. He was wonderful and so easy to work with and answered every question I had. He definitely listened to me and my concerns did not push me into purchasing a high-end system which I didn’t need. The technicians arrived at 8am and were finished with the entire installation by 1pm. They were very courteous and left my house in pristine condition. I HIGHLY recommend Mannix! They always returned my calls and emails right away, and Eric made sure I received all of my equipment on time–even with Carrier factory delays/limited supplies due to COVID. So glad I chose Mannix. I love my brand new Carrier system and my cold house during these hot and humid days.


We were in desperate need of a fix on our AC system during the July heatwave. The issue arose on a Saturday. Mannix came to the rescue in short order, fixed it, and at a reasonable price.

Silvio G was the technician, and he was GREAT.

We would definitely use Mannix again!

Patricia Ryan

I have been using Mannix for years. They have replaced my HVAC system and I have them do maintenance twice a year. The past couple of visits have been done by Ramiro. He is professional, polite, knowledgeable, and very helpful in assisting me with tips on the best ways to operate my system. Today, he installed a water safety device and taught me exactly how it works and how to reset it. I’m so impressed with him! I will continue with Mannix for years to come as I find them to be very reputable and reliable. Thank you!

Rachel Craft

I’ve been using Mannix for years and have never been disappointed. They’ve replaced my HVAC, hot water heater and installed a humidifier on my furnace. Whenever I need them, they can get me on the schedule in a timely manner. All the personnel are great and I trust Jerry and his team with their recommendations and the work they do. Would highly recommend.

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