
Your Trusted Plumbers, Heating & AC Repair Experts in Newmarket, NH
Since 1987, GSMS has been proud to offer top-notch HVAC services to residents of Newmarket, NH. With over three decades of experience, our family-owned business has built a reputation for excellence, reliability, and outstanding customer service.
HVAC Service
We provide a comprehensive range of HVAC services, including air conditioning repair, replacement, and maintenance, as well as heating services for furnaces and boilers. Our expert technicians are also skilled in installing and maintaining ductless mini-split systems, ensuring that your home stays comfortable year-round.
AC Repair and Furnace Installation
At GSMS, we use only the highest quality products from leading manufacturers, guaranteeing efficient and long-lasting solutions for your HVAC needs. Whether you need a quick repair, a complete system installation, or regular maintenance, our team is dedicated to providing personalized service tailored to your specific requirements.
Don’t let HVAC issues disrupt your comfort—call GSMS today at 603-424-8258 to schedule your HVAC service in Newmarket, NH, and experience the difference of working with trusted local professionals.
Local Newmarket Plumbers
In addition to our heating and air conditioning services, we offer top-quality plumbing services to the residents of Newmarket, NH. With over three decades of experience, our family-owned business has established a reputation for trust, reliability, and exceptional customer care.
Plumbing Service When You Need It
Our comprehensive plumbing services include water heater repair, replacement, and maintenance for both tank and tankless models, ensuring your home has a consistent supply of hot water.
We also specialize in kitchen plumbing, from faucet and sink installations to dishwasher and water line services. In the bathroom, our expert plumbers handle everything from toilet and shower repairs to vanity plumbing and pipe replacement.
Don’t let plumbing issues disrupt your daily routine—call GSMS today at 603-424-8258 to schedule your plumbing service in Newmarket, NH, and experience the peace of mind that comes with working with trusted local professionals.
Get the Best Plumbing & HVAC Service near Newmarket
At GSMS, we use only the highest quality materials and the latest techniques to provide efficient and long-lasting solutions for your plumbing, heating and cooling needs. Whether you require a quick repair, a complete installation, or regular maintenance, our team is committed to delivering personalized service tailored to your home’s unique requirements.
Recent Jobs and Reviews in Newmarket, NH
Our Local Reviews by City
- Amherst, NH (9)
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- York, ME (1)
Job Locations and Reviews

<p>Installation of a standalone dehumidifier to serve the finished basement room. The unit will be installed on the unfinished side of the basement, positioned in the location discussed.</p><p>Small sections of ductwork will be installed, connected to two 12" x 12" white metal wall registers (one low and one high) in the finished room to ensure optimal dehumidification. A condensate pump will be installed to drain into the main waste line, with proper plumbing including a backflow preventer to prevent any sewage from exiting the new drain line. A dedicated electrical circuit will be installed from the main panel to the dehumidifier location.</p><p>While on-site, we will also re-seal the existing mini-split line that enters the structure near the electrical panel.</p>
GSMS did an excellent job with our mini split! We are very happy with their work!

Installation of a single-zone mini-split system to provide cooling and supplemental heating to the home. This proposal includes one outdoor unit and one indoor wall-mounted head, serving the first-floor great room area. Supplemental cooling will work its way into the main living floor, with the understanding that temperatures will be skewed from one side of the home to the other. The outdoor unit will be installed on the backside of the home, to the right of the deck. It will serve the indoor wall-mounted unit in the great room, installed above the wood stove. A dedicated electrical circuit will be installed to serve the system. Important Note: This is a non-HyperHeat unit and is designed to provide reliable cooling and supplemental heating, with heating operation effective down to outdoor temperatures of approximately 20°F.

I found the leaking hybrid water heater tank to be cracked. I replaced it under warranty. Thank you!
Jack was on time and professional upon his arrival to my home. He quickly diagnosed the problem with my hot water heater and had it fixed on the same day. Granite State Mechanical offers unsurpassed customer service and expertise in the area of heating plumbing and cooling. I tell all my neighbors how great they have treated me, and I am so glad I chose GSM to install and service my home HWH and Mini split.
We thank you for sharing your positive experience. It made our day.

Pm on hot water heater,checked upper and lower elements,condensate drain and pump,cleaned air filter and checked sediment in tank.Everything is ok

GSMS HomeClub heating visit went great! Your Mitsubishi heat pump mini split is ready for another season of dependable and clean operation.