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Our Service Area

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 466 customer reviews

Customers say: The overall sentiment across these reviews is overwhelmingly positive, reflecting high levels of customer satisfaction and appreciation. Customers consistently express enthusiasm about the quality of service they received, with recurring praise for professionalism, expertise, and efficiency. A dominant theme throughout is the technical skill and knowledge demonstrated by the service team, with many reviewers highlighting how thoroughly problems were diagnosed and resolved. The interpersonal qualities of the technicians emerge as another strong positive trend, with customers frequently describing them as friendly, personable, pleasant, and respectful. Communication stands out as a particularly valued aspect, with reviewers appreciating clear explanations, patience in answering questions, and being kept informed throughout the service process. Timeliness and punctuality are consistently mentioned as strengths, alongside respect for customers' property and maintaining clean, orderly work practices. Many customers express strong loyalty and trust in the company, with several indicating they are repeat customers or plan to continue using the service. The tone is enthusiastic and grateful, with multiple reviewers offering strong recommendations and expressing genuine happiness with the results. Overall, these reviews paint a picture of a service provider that excels in both technical competence and customer care, creating consistently positive experiences that foster long-term customer relationships.

Job Locations and Reviews

Review
Quentin was friendly, personable, knew his business, and professional. Answered all my questions. Made recommendations that made sense. Would use him and GSMS anytime
Dale - Nashua, NH 03062
Qwentin G.
Qwentin G. Checked in
Completed the AC maintenance today. Everything went great. Please see the attached form.
Bedford, NH 03110
Jack D.
Jack D. Checked in
Well Water test Comprehensive + radon.
Amherst, NH 03031
Completed the AC maintenance and the furnace maintenance today. Everything went great! Please see the attached maintenance forms. I will send over the estimate for the hot water heater repairs.
Completed the AC maintenance and the furnace maintenance today. Everything went great! Please see the attached maintenance forms. I will send over the estimate for the hot water heater repairs.
Qwentin G.
Qwentin G. Checked in
Completed the AC maintenance and the furnace maintenance today. Everything went great! Please see the attached maintenance forms. I will send over the estimate for the hot water heater repairs.
Nashua, NH 03062
Na
Na
Qwentin G.
Qwentin G. Checked in
Na
Dover, NH 03820
Mark D.
Mark D. Checked in
This proposal outlines the replacement of your failed 40-gallon Bradford White power-vented natural gas water heater. Because your tank is currently covered under the manufacturer's warranty, the physical cost of the new tank itself is covered. The pricing in this proposal strictly covers the professional labor, the distributor's warranty processing fee, the necessary structural plumbing modifications, and the required safety code upgrades to properly install the new unit. Scope of Work 1. Demolition & Warranty Processing Removal: We will safely drain, disconnect, and remove your existing failed water heater. Warranty Handling: GSMS will handle the logistics of returning the failed tank and will cover the $100 warranty processing fee charged by the distributor on your behalf. 2. Equipment Installation & Code Upgrades The New Tank: We will supply and install your new warranty-replacement 40-gallon Bradford White power-vented natural gas water heater in the exact same footprint. Conn
Amherst, NH 03031
Qwentin G.
Qwentin G. Checked in
Removed the dip tube and the anode rod. Cleaned the threads on the tank really well. Taped and used pipe sealant on the threads. I let the client know that the wet sensor got a little bit of water on it so I left it unplugged so it can dry out.
Bedford, NH 03110
Completed the Central AC maintenance and the mini split maintenance. Everything went great! I found inside of the furnace two gas leaks and a gas leak below the shut-off for the furnace. After repairing the leaks I gas sniffed all lines with my electronic sniffer and everything was good. No more leaks. Please see the attached form as well.
Completed the Central AC maintenance and the mini split maintenance. Everything went great! I found inside of the furnace two gas leaks and a gas leak below the shut-off for the furnace. After repairing the leaks I gas sniffed all lines with my electronic sniffer and everything was good. No more leaks. Please see the attached form as well.
Qwentin G.
Qwentin G. Checked in
Completed the Central AC maintenance and the mini split maintenance. Everything went great! I found inside of the furnace two gas leaks and a gas leak below the shut-off for the furnace. After repairing the leaks I gas sniffed all lines with my electronic sniffer and everything was good. No more leaks. Please see the attached form as well.
Milford, NH 03055
Review
very courteous, efficient. a pleasure to work with.
Peter - Merrimack, NH 03054
Qwentin G.
Qwentin G. Checked in
Installed new thermostat. Tested operation and everything was working as it should.
Windham, NH 03087
Jack D.
Jack D. Checked in
This proposal outlines the rapid replacement of your existing, failed Fujitsu multi-zone system. Because your current system has suffered a refrigerant leak, we will completely remove the old equipment and replace it with a highly reliable Mitsubishi 2-zone ductless system. Based on our load calculations, your current capacities are perfectly sized for the spaces. We will be installing a standard Mitsubishi heat pump (non-Hyper Heat), which acts as a direct equivalent to your previous system. This will provide you with excellent, reliable air conditioning throughout the summer, as well as highly efficient supplemental heating during the milder spring and fall shoulder seasons. Scope of Work 1. Demolition & Equipment Removal Safe Extraction: We will safely recover any remaining refrigerant, disconnect the electrical components, and completely remove the existing Fujitsu outdoor condenser and the two indoor wall heads. 2. Indoor Equipment (2 Zones) We will supply and install two (2
Merrimack, NH 03054
Review
CALL BACK IS IN THE WORKS- THERMOSTAT IS BLACK - NO REPSOPONSE.
Montcalm - Nashua, NH 03060
Mark D.
Mark D. Checked in
Found overflow switch off.Looks like air was blowing on it from door cover moved switch .
Nashua, NH 03060
Review
First time using this company, and I was very impressed with the service as well as the knowledge of the Technician
Eileen - Hooksett, NH 03106
Review
Excellent as usual
John - Hollis, NH 03049
Review
Great service, right on time. Jack did a great job picking out my new faucets.
Lisa - Merrimack, NH 03054
Review
Qwentin was right on time and provided friendly and thorough service for my boiler. He answered all of my questions and the pricing felt very fair. Thanks!
Daniel - Manchester, NH 03102
Review
Arrived quickly to my situation and solved the problem immediately
Kathleen - Merrimack, NH 03054
Review
Excellent service, hard working individual, arrived on time
Kathleen - Merrimack, NH 03054
Review
Great job
Levasseur - Manchester, NH 03102
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 service again. On time and professional. I 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
Prompt, profession and knowledgeable. Always a great experience
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
I needed to have shut off valves under my kitchen sink and a new hose attachment on my sprayer since the cheap plastic tubing was cracked. Mark was punctual, professional and extremely knowledgeable regarding the job. I am always impressed with GSM and how they run their family business. Mark completed the job quickly and efficiently. I can trust GSM and will continue to seek their help in the help in the future. GSM has installed a mini split, oil boiler, hot water heater in my home and I would highly recommend them to family and friends.
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.

Trusted Quality & Service