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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 366 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 plumbing visit today. I started off with completing the maintenance on the Rinnai tankless water heater. I ran a cleaner through it for 40 minutes. Next I flushed it out with 10 gallons of water. I cleaned the water inlet screen. I vacuumed out the inside of the unit and the air filter. I inspected all the fixtures and drains and everything looked great!
Bedford, NH 03110
Bow, NH - Pm on rinnai
Mark D.
Mark D. Checked in
Pm on rinnai
Bow, NH 03304
Bedford, NH - I started off with replacing the failing inducer capacitor on the basement furnace. Next I replaced the furnace trap and re did the piping. I ran the furnace and tested operation and everything worked as it should and there was no leaks. Next I completed the plumbing maintenance. I started off with running a cleaner for 40 minutes through the Rheem tankless water heater. I then flushed 10 gallons of water through it. I pulled the inlet filter screen and I cleaned it. I vacuumed out the inside of the unit. There was a lot of rust and corrosion inside of the unit. I'd highly recommend thinking about replacing it since the unit is over 20 years old and doesn't look too good inside. Other than that there was no leaks and everything went good today.
Qwentin G.
Qwentin G. Checked in
I started off with replacing the failing inducer capacitor on the basement furnace. Next I replaced the furnace trap and re did the piping. I ran the furnace and tested operation and everything worked as it should and there was no leaks. Next I completed the plumbing maintenance. I started off with running a cleaner for 40 minutes through the Rheem tankless water heater. I then flushed 10 gallons of water through it. I pulled the inlet filter screen and I cleaned it. I vacuumed out the inside of the unit. There was a lot of rust and corrosion inside of the unit. I'd highly recommend thinking about replacing it since the unit is over 20 years old and doesn't look too good inside. Other than that there was no leaks and everything went good today.
Bedford, NH 03110
Londonderry, NH - Install 2 supply valves, cutout old ice maker valve, cutout and bypass water softener system.
Jack D.
Jack D. Checked in
Install 2 supply valves, cutout old ice maker valve, cutout and bypass water softener system.
Londonderry, NH 03053
Qwentin G.
Qwentin G. Checked in
Completed the plumbing inspection today. I started off with inspecting all the fixtures and drains and everything looked really good. I did not flush the indirect water tank due to the age and no record of it being flushed. The water tank is over 11 years old but looks to be in good condition. I labeled a few emergency shut off's as well.
Auburn, NH 03032
Mark D.
Mark D. Checked in
We are going to install the InSinkErator Evolution 1 HP (Advanced Series). While it matches the 1-horsepower strength of your previous unit, the technology inside is completely different. Your old disposal used a single grinding ring, but this new Evolution model uses 4-Stage MultiGrind™ technology. What that means for you: It Liquefies Everything: It has special 'shear rings' and 'undercutters' that slice food into near-liquid form. It can handle things your old unit couldn't, like celery and potato peels, without jamming. It's Silent: It features the highest level of 'SoundSeal' insulation, making it the quietest disposal on the market—you will barely hear it running compared to your old one.
Bedford, NH 03110
Jack D.
Jack D. Checked in
Air bound second floor loop due to mono flow tee piping. Installed air vent to air in purging of system. We ensured warm supplies and returns! Thank you.
Milford, NH 03055
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
Boiler PM! Everything went great!
Boiler PM! Everything went great!
Jack D.
Jack D. Checked in
Boiler PM! Everything went great!
Gilmanton, NH 03837
Qwentin G.
Qwentin G. Checked in
Replaced the deteriorating anode rod. Bled all the air out of the lines. Tested and made sure there was no leaks, everything went great.
Hooksett, NH 03106
Jack D.
Jack D. Checked in
Low psi. Filled up. No visible leaks anywhere. Heat is working.
Exeter, NH 03833
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
Fantastic service
Laszlo - Manchester, NH 03104
Review
Very knowledgeable & very helpful
Steve - Nashua, NH 03064
Review
Quentin arrived in time, was courteous and professional and answered all my questions.
BJ - Merrimack, NH 03054
Review
Excellent and professional work , all great
Alison - Bedford, NH 03110
Review
Qwentin is awesome, very knowledgeable and an overall good guy
James - Manchester, NH 03104
Review
Excellent!!!
Kathleen - 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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