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
×
Excellence Defines GSMS
Comprehensive, Expert Care for Every Room
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

Douglas BrodR
21:06 10 Sep 25
The technician, Mark, was very knowledgeable of Rinnai hot water heaters and explained things clearly.No other vendors who have come in the past, did or recommended, the heat exchanger cleaning Mark did. In fact the last service provider just said you need a new unit without even looking at it.There dispatch via texting, email or phone was simple and up to date and on time.Very happy with GSMS and will be using them in the future.

Patrice Sabbagh
17:34 26 Aug 25
GSMS is reliable and very knowledgeable. It is a comforting and safe feeling working with them.

John Spellacy
19:59 30 Jul 25
Jack was very knowledgeable and helpful. Thank you for everything!