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Proudly Serving New Hampshire Homeowners

At GSMS, we are proud to serve New Hampshire with our comprehensive range of HVAC and plumbing services.

As a family-owned business with 35+ years of experience, we have built a reputation for excellence, reliability, and outstanding customer care. Our skilled technicians are dedicated to providing top-quality repairs, installations, and maintenance tailored to meet the unique needs of New Hampshire homeowners.

Explore our service area below, read reviews in your city, and see why homeowners across New Hampshire trust GSMS for their HVAC and plumbing needs.

Contact us online today or call 603-424-8258 to schedule your service and experience the GSMS difference.

Recent Jobs and Reviews

Rated 5.0 out of 5 stars based on 372 customer reviews

Customers say: The recent reviews exhibit a predominantly positive sentiment, with recurring themes of satisfaction, professionalism, and expertise. Customers express gratitude, recommend the company, and acknowledge the quality of the work performed. Positive reviews frequently mention friendly and knowledgeable technicians, timely responses, and efficient service. Negative reviews are minimal and do not represent a clear, recurring trend. Overall, the reviews suggest a positive experience with the company, with many customers expressing satisfaction with their HVAC and plumbing needs.

Job Locations and Reviews

Furnace PM.
Furnace PM.
Jack D.
Jack D. Checked in
Furnace PM.
Manchester, NH 03102
Completed the gas furnace maintenance today. I started off with checking all the wiring connections and everything looked good. I pulled and cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I vacuumed out the inside of the furnace and the filter box. The air filter looked very clean so I left it in. I checked incoming and outgoing gas pressures and those were according to manufacture specifications. Lastly I ran the unit in low and high fire and performed a combustion analyzer test. This checks the units CO, CO2 and oxygen levels. The furnace was running great!
Completed the gas furnace maintenance today. I started off with checking all the wiring connections and everything looked good. I pulled and cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I vacuumed out the inside of the furnace and the filter box. The air filter looked very clean so I left it in. I checked incoming and outgoing gas pressures and those were according to manufacture specifications. Lastly I ran the unit in low and high fire and performed a combustion analyzer test. This checks the units CO, CO2 and oxygen levels. The furnace was running great!
Qwentin G.
Qwentin G. Checked in
Completed the gas furnace maintenance today. I started off with checking all the wiring connections and everything looked good. I pulled and cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I vacuumed out the inside of the furnace and the filter box. The air filter looked very clean so I left it in. I checked incoming and outgoing gas pressures and those were according to manufacture specifications. Lastly I ran the unit in low and high fire and performed a combustion analyzer test. This checks the units CO, CO2 and oxygen levels. The furnace was running great!
Nashua, NH 03063
Jack D.
Jack D. Checked in
I found the cause of no heat to be a plugged furnace drain. I disassembled and cleaned the furnace trap and drain. I tested for operation after. Thank you!
Bedford, NH 03110
Qwentin G.
Qwentin G. Checked in
Found that the gas valve has failed after only being in for about 5 months. I was able to turn on the heat pump and we are running that for now until the gas valve is able to be replaced. The office will reach out to you as soon as we know when the part is coming in.
Merrimack, NH 03054
Jack D.
Jack D. Checked in
No heat for furnace caused by bad thermostat. I replaced it today. The ductless system was not working due to the outdoor power being shutoff via the disconnect.
Londonderry, NH 03053
Qwentin G.
Qwentin G. Checked in
Completed the plumbing maintenance today. The indirect water tank is from 2003 so I did not drain it due to the age. I inspected all the drains and the fixtures and everything looked great. The only thing I noticed was the expansion tank has failed. The client also wanted us to run drain cleaner in the bathroom sink and bathtub. I will send over two separate estimates.
Manchester, NH 03102
Jack D.
Jack D. Checked in
GSMS HomeClub plumbing visit. Everything went well. There are only a few repairs that I reccomend and I have sent over in an estimate!
Amherst, NH 03031
Review
Excellent service and communication. A great family business.
Paul - Nashua, NH 03062
Mark D.
Mark D. Checked in
Checked system everything looked fine added a couple of han gers.She doesn't like the thermostat we put in going to look for simple with better df.
Merrimack, NH 03054
Jack D.
Jack D. Checked in
Could not find cause of error code. System running properly. I replaced dripping relief valve. Thank you!
Windham, NH 03087
Review
Quentin gave me all the information I requested and was exceptionally polite and did a through job. I highly recommend him and GSMS company !
John - Weare, NH 03281
Found that some wires were chewed by a mouse. Waiting for Mitsubishi to call me back to get availability on parts and or a new unit. We will let you know as soon as we hear back from them.
Found that some wires were chewed by a mouse. Waiting for Mitsubishi to call me back to get availability on parts and or a new unit. We will let you know as soon as we hear back from them.
Qwentin G.
Qwentin G. Checked in
Found that some wires were chewed by a mouse. Waiting for Mitsubishi to call me back to get availability on parts and or a new unit. We will let you know as soon as we hear back from them.
Weare, NH 03281
Review
We use GSMS for all our bathroom remodels! Mark, Jack and Zak have been awesome to work with.
Peggy - Granite State Home Improvements - Strafford, NH 03884
Review
Excellent service.
Kathleen - Merrimack, NH 03054
Review
Amazing service as usual!!!
Scott - Merrimack, NH 03054
Review
Professional service
Paul - Nashua, NH 03062
Review
Qwentin, once again, did a exceptional job. He is always professional, courteous and gets the job done right and quickly. Qwentin and GSMS never let me down!
Jared - Hooksett, NH 03106
Review
Full explanation of the work to be completed and suggestions for future services . Answered all my questions. Very professional and knowledgeable.
Paul - Nashua, NH 03062
Review
Qwentin is professional, friendly, and efficient! Excellent service.
Ginger - Hollis, NH 03049
Review
Both guys very helpful & solved the problem
Steve - Nashua, NH 03064
Review
Love dealing with this company. Their techs are always prompt, efficient and courteous. We've been happy to be their customer since 2010.
Skip Sagris - Bow, NH 03304
Response from GSMS Air•Heating•Plumbing:

Thank you so much for the kind words and for being part of the GSMS family since 2010! It means the world to us to have earned your trust over the years. I’m proud of our team for continuing to deliver the kind of service that keeps clients like you coming back. We truly appreciate your loyalty and support. – Zak D., Second-Generation Owner

Review
Qwentin was on time, very friendly and professional. He was able to identify the issue, communicate it effectively, and then fix it. Highly recommend.
Phil Cutler - Bedford, NH 03110
Response from GSMS Air•Heating•Plumbing:

Thank you so much for the kind words and for trusting GSMS to take care of your home. Qwentin is a rising star on our team, and it means a lot to hear that his professionalism and communication made a strong impression. As a local, family-run business, we’re grateful for your recommendation and honored to have earned your trust. – Zak D., Second-Generation Owner

Review
Great water heater service. On time and professional l He gave me some helpful tips on other water related issues. Highly recommend GSMS.
Katherine Turner - Exeter, NH 03833
Response from GSMS Air•Heating•Plumbing:

Thank you for the great review! I’m glad to hear our Specialist was able to get your water heater squared away and offer some extra tips while he was there. We always aim to go beyond just the repair, and I really appreciate you taking the time to share your experience. Thanks for choosing GSMS — it means a lot to our family and our team. – Zak D., Second-Generation Owner

Review
David DiNardo - Bedford, NH 03110
Response from GSMS Air•Heating•Plumbing:

Thank you for the 5 stars, David! We really appreciate you choosing GSMS and supporting our family-run team. If there’s ever anything more we can do for you, don’t hesitate to reach out. – Zak D., Second-Generation Owner

Review
claire lafond - Merrimack, NH 03054
Response from GSMS Air•Heating•Plumbing:

Thank you so much for the 5 stars, Claire! We’re grateful for your support and truly appreciate you choosing GSMS. It means a lot to our family and our entire team. – Zak D., Second-Generation Owner

Review
Great work, fair prices.
Tom Grasse - Manchester, NH 03104
Response from GSMS Air•Heating•Plumbing:

We thank you for sharing your positive experience. It made our day.

Review
top notch service, always professional. would recommend to anyone needing HVAC service, repair or install.
Ben Bouchard - Nashua, NH 03062
Response from GSMS Air•Heating•Plumbing:

It was a pleasure serving you and your family. Thank you for sharing your kind words with us. It means the world to us and to our entire team!

Review
Had an issue with our heat pump. Reached out for assistance and they had someone on site that afternoon. Problem was resolved quickly. Super friendly service. The tech was exceptionally friendly and an excellent communicator. Highly recommend
Mark Cooke - Greenland, NH 03840
Response from GSMS Air•Heating•Plumbing:

It was a pleasure serving you and your family. Thank you for sharing your kind words with us. It means the world to us and to our entire team!

Review
Adam, Quin and Mark did a wonderful job installing my replacement oil boiler and oil tank. I have trusted GSM for 3 installs at my house because of their professionalism, workmanship, honesty, transparency and integrity for how they conduct their family business. Everyone who has worked at my house has always been informative, on time and respectful. I would recommend GSM to anyone who needs to have major plumbing or heating/cooling done in their home. Gina in customer service is the best at relaying information and gets back to you in a timely fashion. Zak is wonderful to work with and the entire team at GSM treats you with kindness. Thank you again for another wonderful experience because when it comes to your home it is one of the largest investments you will make in your life, and I trust GSM to be there for me in the future.
Kimberly Cichon - Newmarket, NH 03857
Response from GSMS Air•Heating•Plumbing:

We thank you for sharing your positive experience. It made our day.

Review
As usual, Jack's work is stellar.
Bob Bedrosian - Merrimack, NH 03054
Response from GSMS Air•Heating•Plumbing:

We are so glad to hear that you had a good experience.

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