Premier Heating, Air & Plumbing from a Family-Run New Hampshire Business
We're Local. We're Family-Owned
HVAC Contractor & Plumber Services For Homes & Businesses
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Excellence Defines GSMS
Comprehensive, Expert Care for Every Room
GSMS Joins Lennox in Spreading Warmth Through the “Feel the Love” Program
This year, our team had the privilege of installing a brand-new Lennox system for a local public figure whose selfless work continues to empower young women and strengthen our community.
Trusted Quality & Service
Since 1987
Why Choose GSMS
Family Business
You're supporting a local NH family with its second generation of ownership, not some big out-of-state corporation.
WOW Warranty
We only install systems that meet our standards. That means we stand behind them with industry-leading labor warranties.
GSMS Smart Monitoring
Our unique sensors analyze your air and heating systems daily. This allows us to predict issues before they happen.
Helping Our Community
Through our "We Heart Local" initiative, we donate a portion of our profits every month to local NH organizations in need!
Great Service Promise
Affordable pricing, 5-star service, and pride in our work. If you're not satisfied, we'll make it right. It's how we've worked since 1987.
Let's Make Home Enjoyable Again.
Countless 5-Star Reviews
Great Service Makes For Great Reviews
Nadeau JW
21:12 23 Dec 25
Mark and his team always does a great job! They understand our request and complete work in a timely manner. They also go the extra mile to check every aspect of the heating system. The price is reasonable too! That is why we always call them :)
Larry Casey
20:52 19 Dec 25
This was our first experience with GSMS and our service tech Quentin was a cut above what we’ve been used to. Friendly, knowledgeable, efficient and totally focused on satisfying our needs. It’s a comfort to know we have this level of service available to us when needed.
melissa grover
15:27 17 Dec 25
Mark arrived on time and was professional. He did a great job cleaning my boiler and offered a solution to an issue that saved me money. He was even able to navigate my messy basement with ease.
