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
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
Replace the sediment filter and O-ring supplying cold water to the Rheem tankless water heater.
Excellent Service
I completed the Rinnai maintenance today. I started off with running a cleaner through it for 35 minutes. Next I flushed 10 gallons of water through it. I cleaned the water inlet screen. I vacuumed out the inside of the unit. I checked incoming gas pressure and that was according to manufacturer specifications. The water heater is 16 years old but looks to be in good shape. Everything went good today.
I found the leak at the water heater to be caused by a leaking expansion tank. I replace it and tested for leaks. All set thank you!
When the fan runs at high speed, the plastic is vibrating. That is the sound that we are hearing.
Replaced the leaking pressure relief valve. Bled the air out of all the zones. Checked the glycol level and it was in range. Made sure all returns came back hot.
Today I replaced the old thermostat cable that mice had destroyed. I ran an 8 conductor cable for the future system in mind.
Furnace PM.
Completed the gas furnace maintenance today. I started off with checking all the wiring connections and everything looked good. I pulled and cleaned the flame sensor. I flushed the trap and condensate pump with cleaner. I vacuumed out the inside of the furnace and the filter box. The air filter looked very clean so I left it in. I checked incoming and outgoing gas pressures and those were according to manufacture specifications. Lastly I ran the unit in low and high fire and performed a combustion analyzer test. This checks the units CO, CO2 and oxygen levels. The furnace was running great!
I found the cause of no heat to be a plugged furnace drain. I disassembled and cleaned the furnace trap and drain. I tested for operation after. Thank you!
Excellent service and communication. A great family business.
Quentin gave me all the information I requested and was exceptionally polite and did a through job. I highly recommend him and GSMS company !
We use GSMS for all our bathroom remodels! Mark, Jack and Zak have been awesome to work with.
Excellent service.
Amazing service as usual!!!
Professional service
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!
Full explanation of the work to be completed and suggestions for future services . Answered all my questions. Very professional and knowledgeable.
Qwentin is professional, friendly, and efficient! Excellent service.
Love dealing with this company. Their techs are always prompt, efficient and courteous. We've been happy to be their customer since 2010.
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
Qwentin was on time, very friendly and professional. He was able to identify the issue, communicate it effectively, and then fix it. Highly recommend.
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
Great water heater service. On time and professional l He gave me some helpful tips on other water related issues. Highly recommend GSMS.
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
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
top notch service, always professional. would recommend to anyone needing HVAC service, repair or install.
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!
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
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!
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.
We thank you for sharing your positive experience. It made our day.
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