Granite State Mechanical Services, LLC

A 5.0 average across 257 Google ratings is the kind of number that usually means a thin sample. This one isn't: 154 written reviews going back to 2021, and 34 of them in the last six months alone. Granite State Mechanical Services — GSMS to the customers who keep writing about it — runs heating, cooling and plumbing calls out of Manchester, and its New Hampshire HVAC licence is active. Reviewers describe a family business and name the same handful of people over and over: Zak, Adam, Mark, Jack, Qwentin, and Gina handling the scheduling. What customers keep describing is diagnosis and explanation rather than a fast push to replace. Writing in 2025, one homeowner said Mark knew Rinnai water heaters well enough to clean the heat exchanger — work no previous vendor had done or even recommended, one of them having said she simply needed a new unit without looking at it. In March a couple hired the company to install a make-up air system for a new stove and hood during a kitchen remodel, after collecting five quotes and hearing several approaches. Jack came out on the Fourth of July and got a boiler diagnosed and running again. A new customer in May was surprised to get service the same day she called. The bigger jobs take real time. A July install of five mini-split heads ran two and a half days, so pin down the schedule if you're replacing a whole system rather than fixing one part of it. And while heating and cooling dominate the calls, plumbing genuinely is part of the work: reviewers describe a spigot fixed, a walk-through of a house's pipes and water system, and hybrid and tankless water heater installs. On price, the comments run one way. A homeowner replacing a boiler in 2025 said the quote came in well under three other companies. A commenter in r/newhampshire named GSMS as one of two shops he uses for a lot of work and said both give fair prices — one anonymous voice, but it points the same direction as the reviews. This is the right call for a New Hampshire homeowner who wants one small crew for the annual furnace clean and, eventually, for the system that replaces it. Its BBB page carries an A+ and accreditation. Ask for the written options up front: a customer writing in 2021 described getting a free estimate with several options and no pressure, and that's the pattern worth holding them to.