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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 316 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

Mark D.
Mark D. Checked in
Replaced shower cartilage
Barrington, NH 03825
Hudson, NH - Replace 2 - 3/4 female adapters solder. Checked for leaks and all set!
Jack D.
Jack D. Checked in
Replace 2 - 3/4 female adapters solder. Checked for leaks and all set!
Hudson, NH 03051
Completed the maintenance on all four gas boilers. On all of them I pulled out the burner tubes and cleaned them. I vacuumed out the burner box. I cleaned the flame sensors as well. Inspected all the boiler accessories. The only unit that I found any issues with was the boiler that serves 117 Main St. There is a leaking high vent and a leaking relief valve as well.
Completed the maintenance on all four gas boilers. On all of them I pulled out the burner tubes and cleaned them. I vacuumed out the burner box. I cleaned the flame sensors as well. Inspected all the boiler accessories. The only unit that I found any issues with was the boiler that serves 117 Main St. There is a leaking high vent and a leaking relief valve as well.
Qwentin G.
Qwentin G. Checked in
Completed the maintenance on all four gas boilers. On all of them I pulled out the burner tubes and cleaned them. I vacuumed out the burner box. I cleaned the flame sensors as well. Inspected all the boiler accessories. The only unit that I found any issues with was the boiler that serves 117 Main St. There is a leaking high vent and a leaking relief valve as well.
Nashua, NH 03060
Nashua, NH - Rinnai Tankless water heater maintenance as part of HomeClub! Thank you!
Jack D.
Jack D. Checked in
Rinnai Tankless water heater maintenance as part of HomeClub! Thank you!
Nashua, NH 03062
Mark D.
Mark D. Checked in
Did work from estimate
Barrington, NH 03825
Finish boiler maintenance agreement work.
Finish boiler maintenance agreement work.
Jack D.
Jack D. Checked in
Finish boiler maintenance agreement work.
Londonderry, NH 03053
Qwentin G.
Qwentin G. Checked in
I started off with pulling out all the air filters and cleaning them with soap and hot water. I rinsed all the indoor coils with coil cleaner and then rinsed with water. I cleaned the out side of the unit with a wet rag. I completed the ERV maintenance. I cleaned the filters with soap and hot water. I inspected all the components inside. I vacuumed out the core and the inside of the unit. I cleaned the inside of the unit with a wet rag as well.
Pelham, NH 03076
Completed gas piping to gas generator
Completed gas piping to gas generator
Adam P.
Adam P. Checked in
Completed gas piping to gas generator
Merrimack, NH 03054
Review
Service
Guimont - Manchester, NH 03103
Jack D.
Jack D. Checked in
Replace failed zone board with oem replacement. Test operations of each zone. Replace supply air sensor in RTU for the economizer control. Test operations. All set, thank you!
Nashua, NH 03062
Replacement of the existing gas furnace and central air unit with a new high-efficiency variable-speed system. A new furnace will be installed with new 2" venting for fresh air and exhaust. The existing CSST gas line will be replaced with black iron piping running from the gas regulator to the new furnace. The return drop will be modified to allow for the installation of our AirBear filtration unit, and all other connections will be remade. The new A/C unit will be placed in the same location, installed on a new gravel footing and a composite unit pad, with a new disconnect and updated electrical connections. The entire system operation will be controlled by a new Lennox S40 smart thermostat.
Replacement of the existing gas furnace and central air unit with a new high-efficiency variable-speed system. A new furnace will be installed with new 2" venting for fresh air and exhaust. The existing CSST gas line will be replaced with black iron piping running from the gas regulator to the new furnace. The return drop will be modified to allow for the installation of our AirBear filtration unit, and all other connections will be remade. The new A/C unit will be placed in the same location, installed on a new gravel footing and a composite unit pad, with a new disconnect and updated electrical connections. The entire system operation will be controlled by a new Lennox S40 smart thermostat.
Adam P.
Adam P. Checked in
Replacement of the existing gas furnace and central air unit with a new high-efficiency variable-speed system. A new furnace will be installed with new 2" venting for fresh air and exhaust. The existing CSST gas line will be replaced with black iron piping running from the gas regulator to the new furnace. The return drop will be modified to allow for the installation of our AirBear filtration unit, and all other connections will be remade. The new A/C unit will be placed in the same location, installed on a new gravel footing and a composite unit pad, with a new disconnect and updated electrical connections. The entire system operation will be controlled by a new Lennox S40 smart thermostat.
Bow, NH 03304
Review
Excellent Service!
E Z - Manchester, NH 03102
Review
Quick service call to replace thermostat. Done in about 15 minutes, explained the workings. Very satisfied Great service as usual
Joseph - Merrimack, NH 03054
Review
Our furnace kept shutting off. Mark identified the issue and resolved the problem. Very much appreciate the service!
Oakwood Prop - Milford, NH 03055
Review
Jack was polite and very neat.
Sharon - Merrimack, NH 03054
Review
We have been working with GSMS for 8 years. They provide the best service for installs and maintenance. The people are very professional, friendly and do great work. Today Qwentin was the tech doing the service maintenance. This young man came at the time scheduled, knew what he was doing and did excellent work. If you are in need for heating, air conditioning and plumbing work, this is the company for you!
Claire - Merrimack, NH 03054
Review
Jack did a great job. Provided a lot of good information. Thank you
Don - Merrimack, NH 03054
Review
Excellent service
Kathleen - Merrimack, NH 03054
Review
Excellent Service
Sharon - Merrimack, NH 03054
Review
Excellent
Sharon - Merrimack, NH 03054
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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