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Our Service Area

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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 422 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

Qwentin G.
Qwentin G. Checked in
Completed the first floor mini split maintenance and the third floor central air maintenance. Everything went good for the third floor. The first floor unit I had to add two and a half pounds of R410A refrigerant. A year ago I added 1 lb so the leak is definitely getting bigger. Please see the attached forms.
Manchester, NH 03104
Jack D.
Jack D. Checked in
Planned AC service as part of maintenance agreement. Everything looked good. I repaired a few electrical connections in both condensers.
Londonderry, NH 03053
Qwentin G.
Qwentin G. Checked in
Completed the AC maintenance today. Everything is running great. Please see the attached form.
Bedford, NH 03110
Lennox propane Furnace Maintenance.
Lennox propane Furnace Maintenance.
Jack D.
Jack D. Checked in
Lennox propane Furnace Maintenance.
Deerfield, NH 03037
Jack D.
Jack D. Checked in
Mitsubishi system not working due to two zones being in opposite function modes.
Greenland, NH 03840
Jack D.
Jack D. Checked in
GSMS HOMECLUB AC maintenance.
Amherst, NH 03031
Review
Qwentin did maintenance on multiple hot water tanks. All went well!
Oakwood - Nashua, NH 03060
Mark D.
Mark D. Checked in
Repaired leak on first floor kitchen drain.Had to remove dish washer and refrigerator to cut wall to locate leak.Also resealed master shower drain.
Gilford, NH 03249
Jack D.
Jack D. Checked in
Fujitsu 97 error. Outdoor fan motor has play in shaft. I reccomend replacing to prevent error from happening again.
Candia, NH 03034
Qwentin G.
Qwentin G. Checked in
Checked the charge. Everything is running great!
Bow, NH 03304
Jack D.
Jack D. Checked in
Add UV dye to ductless system.
Nashua, NH 03062
Review
Qwentin was so personable and nice He took his time explaining and did a thorough job I also added the service plan . Gina was the gal that booked my appointment and even added me to a cancellation list I really lucked out I feel great that I have such an awesome company helping me keep my home in great shape !!
Joanne - Manchester, NH 03109
Review
The team was incredibly skilled and expert in their work. Also, the team was respectful of my property. So happy with the result.
Jeff - Stratham, NH 03885
Review
Jack was so knowledgeable and kind. Found the problem right awa
Cecile - Nashua, NH 03062
Review
The service technicians are awesome great friendly guys. The installation was awesome. They did a very efficient job. Glad to be working with GSMS. Thank You!
George - Concord, NH 03303
Review
Quentin is a great ambassador for the Granite State brand! Great guy and trustworthy.
Michael Parker - Windham, NH 03087
Review
Jack arrived promptly @ 8:30a, inspected and troubleshooted to find the problem as to why the AC was not working properly and repaired it promptly. Out the door within 3 hours and AC is working properly. Thanks so much!
Peggy - Manchester, NH 03103
Review
Mark was on time (on the early side of the timeframe) and throughly checked out the ac and plumbing. Pleasant demeanor and went over everything he did and gave the systems a good bill of health.
Nelson - Merrimack, NH 03054
Review
Adam did a great job. He was very professional, experienced, and patient with all my questions and still took the time to do things the right way. GSMS is a hard to find honest and reliable company to work with!
Scott - Auburn, NH 03032
Review
Jack replaced the hot water heater in our condo. He was prompt, very professional, and was very knowledgeable. He was mindful and took care regarding the items stored in the basement. He explained what he did and ensured all questions were answered before he left. GSMS will always service our homes. Thank you Jack and everyone on the GSMS team!
Deb - Hampton, NH 03842
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.

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