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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 340 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

Manchester, NH - GSMS HomeClub Plumbing visit today. There were no issues found other than the high water pressure. We will send a quote to install a Pressure Reducing Valve. Please see the form for details of todays planned service. Thank you!
Jack D.
Jack D. Checked in
GSMS HomeClub Plumbing visit today. There were no issues found other than the high water pressure. We will send a quote to install a Pressure Reducing Valve. Please see the form for details of todays planned service. Thank you!
Manchester, NH 03104
Completed the whole house plumbing inspection. All the fixtures and drains looked great, no leaks. I adjusted the tightness of the handle for toilet on the second floor bathroom. The client said that sometimes it would stick causing the toilet to run constantly. I replaced the clients sentiment filter. He had a new one available for me. Checked for leaks after and there were no leaks. I left them with a new filter for next time. The only thing that I noticed was one of the connections for the new water system that was installed has been and was leaking a little amount of water. We will schedule an appointment to fix that connection.
Completed the whole house plumbing inspection. All the fixtures and drains looked great, no leaks. I adjusted the tightness of the handle for toilet on the second floor bathroom. The client said that sometimes it would stick causing the toilet to run constantly. I replaced the clients sentiment filter. He had a new one available for me. Checked for leaks after and there were no leaks. I left them with a new filter for next time. The only thing that I noticed was one of the connections for the new water system that was installed has been and was leaking a little amount of water. We will schedule an appointment to fix that connection.
Qwentin G.
Qwentin G. Checked in
Completed the whole house plumbing inspection. All the fixtures and drains looked great, no leaks. I adjusted the tightness of the handle for toilet on the second floor bathroom. The client said that sometimes it would stick causing the toilet to run constantly. I replaced the clients sentiment filter. He had a new one available for me. Checked for leaks after and there were no leaks. I left them with a new filter for next time. The only thing that I noticed was one of the connections for the new water system that was installed has been and was leaking a little amount of water. We will schedule an appointment to fix that connection.
Bedford, NH 03110
Jack D.
Jack D. Checked in
Fix issue with fast stat wiring. Everything works properly now. Thank you!
Bedford, NH 03110
Manchester, NH - Replaced air eliminating valve due to old one leaking. Bled air out of the system. Return came back hot.
Qwentin G.
Qwentin G. Checked in
Replaced air eliminating valve due to old one leaking. Bled air out of the system. Return came back hot.
Manchester, NH 03102
Jack D.
Jack D. Checked in
Snake upstairs guest bathroom tub shower.
Merrimack, NH 03054
Qwentin G.
Qwentin G. Checked in
Found that the collector box gasket has failed. We ordered the new gaskets and will let the client know as soon as possible when we can come out to repair it.
Concord, NH 03301
Today I completed the annual maintenance on your Lennox Signature Series natural gas furnace. Everything went smoothly. Please see the maintenance form for details of todays servicing. Thank you!
Today I completed the annual maintenance on your Lennox Signature Series natural gas furnace. Everything went smoothly. Please see the maintenance form for details of todays servicing. Thank you!
Jack D.
Jack D. Checked in
Today I completed the annual maintenance on your Lennox Signature Series natural gas furnace. Everything went smoothly. Please see the maintenance form for details of todays servicing. Thank you!
Bedford, NH 03110
Jack D.
Jack D. Checked in
Snake out the bathroom sink and bathroom tub drain due to continued clogging. Remove piping in wall to access sink drain piping due to snake not being able to make the turn. The TEE was blocked and is now freed up. The blockage is now cleared up. Tested for leaks and all set. Thank you!
Litchfield, NH 03052
Review
Excellent work
Turning - Manchester, NH 03103
Completed the system 2000 gas boiler maintenance today. I started off with checking all the wiring connections and everything looked good. I checked all the boiler accessories and everything looked good. I pulled out the flame sensor and electrode setup and I cleaned it. I checked incoming and outgoing gas pressures and those were according to manufacturer's specifications. I performed a combustion analyzer test that checks the units CO, CO2, oxygen levels and draft. I had to adjust the air setting a tad bit. The client had to replace the draft inducer about 2 years ago because of corrosive build up on the gasket. I found out through tech support that water is making it's way back to the inducer so we should add in a drain line to prevent this. I will send over the estimate next week for the drain line.
Completed the system 2000 gas boiler maintenance today. I started off with checking all the wiring connections and everything looked good. I checked all the boiler accessories and everything looked good. I pulled out the flame sensor and electrode setup and I cleaned it. I checked incoming and outgoing gas pressures and those were according to manufacturer's specifications. I performed a combustion analyzer test that checks the units CO, CO2, oxygen levels and draft. I had to adjust the air setting a tad bit. The client had to replace the draft inducer about 2 years ago because of corrosive build up on the gasket. I found out through tech support that water is making it's way back to the inducer so we should add in a drain line to prevent this. I will send over the estimate next week for the drain line.
Qwentin G.
Qwentin G. Checked in
Completed the system 2000 gas boiler maintenance today. I started off with checking all the wiring connections and everything looked good. I checked all the boiler accessories and everything looked good. I pulled out the flame sensor and electrode setup and I cleaned it. I checked incoming and outgoing gas pressures and those were according to manufacturer's specifications. I performed a combustion analyzer test that checks the units CO, CO2, oxygen levels and draft. I had to adjust the air setting a tad bit. The client had to replace the draft inducer about 2 years ago because of corrosive build up on the gasket. I found out through tech support that water is making it's way back to the inducer so we should add in a drain line to prevent this. I will send over the estimate next week for the drain line.
Hudson, NH 03051
Windham, NH - Completed the plumbing walkthrough of the house. I checked all the fixtures and drains and the only thing that I noticed was the kitchen sink trap nut was a little bit loose so it's been dripping water. After tightening it, it wasn't dripping anymore. I completed the maintenance on the rinnai. I ran cleaner through it for about 40 minutes. I flushed it after with 10 gallons of water. I cleaned the supply water inlet screen. I vacuumed out the inside of the unit. I checked incoming gas pressure and that was according to manufacturer specifications. Everything went good today.
Qwentin G.
Qwentin G. Checked in
Completed the plumbing walkthrough of the house. I checked all the fixtures and drains and the only thing that I noticed was the kitchen sink trap nut was a little bit loose so it's been dripping water. After tightening it, it wasn't dripping anymore. I completed the maintenance on the rinnai. I ran cleaner through it for about 40 minutes. I flushed it after with 10 gallons of water. I cleaned the supply water inlet screen. I vacuumed out the inside of the unit. I checked incoming gas pressure and that was according to manufacturer specifications. Everything went good today.
Windham, NH 03087
Review
Great service!
Colleen - Manchester, NH 03104
Review
Working with GSMS was a fantastic experience. There was attention to detail from the estimate to the clean up at the end of the project. Especially during the planning process, Zak helped me evaluate different options, quickly readjusted as I changed my mind... without ANY pressure! Superior, prompt communication during the whole (and post) process.
Ethel - Londonderry, NH 03053
Review
No heat emergency situation handled immediately on a Sunday evening. Great service!
Paul - Amherst, NH 03031
Review
Excellent service
Paul - Nashua, NH 03062
Review
Qwentin did the annual maintenance on our furnaces. He checked everything thoroughly via checklist and itemized was done.
Lori B - Nashua, NH 03064
Review
The experience started with Gina in the office who was very responsive and accommodating and made the scheduling process super efficient and friendly. Then Mark came and brought his expertise to my home and systems to point areas of installation failures by the company that installed my system. Just using the basic manual to point out how they cut corners. Mark spent the time to correct the exhaust piping to fix leaks and improve air flow. He was friendly and accommodating.
Nelson - Merrimack, NH 03054
Review
Whenever Mark is on the way, you know it’s gonna be fixed correctly. He is awesome!
Kathleen - Nashua, NH 03064
Review
Mark is always very professional and clearly communicates all options. He and his team are able to accommodate us and get the job done in a timely manner. THANK YOU!
Joyce - Hudson, NH 03051
Review
Arrived on time. Work was completed timely. Cleaned up afterwards. Very pleased with the service.
Charlie - New Boston, NH 03070
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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