Main Stream Mechanical

Two names keep turning up in Main Stream Mechanical's reviews: Nick, who leads the installs, and Brenda, who runs the office. Customers name them the way people name the staff at a shop they've used for a decade — which, for a lot of these reviewers, is exactly what happened. It's a small Amesbury operation. Its BBB page describes a Massachusetts corporation incorporated in 1996 with six employees, Eric Schuberth as president and Brenda Castonguay as office manager, doing residential and commercial plumbing, heating and air conditioning. The company says it has worked Massachusetts and southern New Hampshire for more than 25 years, and lists furnaces, boilers, central and ductless AC, Mitsubishi heat pumps, water heaters and generators. The written history runs 2021 through 2025 — 36 Google reviews behind a 4.9 average across 136 ratings — and heating work dominates it. A homeowner writing in 2023 described an oil-to-gas conversion the company did back in 2012 in Danvers, oil tank removal included, and said the furnace was still running eleven years on; that customer came back for whole-home air conditioning. A 2025 reviewer had the same conversion done and said the crew explained the process and finished on schedule. In 2024, a customer with a 25-year-old oil-fired steam system wrote that the technician tested individual radiators after the repair and left it quieter than before; another that year credited a technician with catching a cracked heater head in a tenant's furnace. Ductless mini-splits are the newer thread. A 2025 bedroom install drew comment for confirmed appointments and for the company arranging the electrical service upgrade itself, so the homeowner didn't have to chase a second trade. Urgency shows up too: a 2023 customer came home to a soaked ceiling and a dead central AC unit and had the whole system replaced against a tight deadline. In 2026 a commenter in r/newhampshire named them, unprompted, as a company they'd had good experiences with. One thing to settle before booking. Its Massachusetts HVAC licence, number 12625-SM-J1, came back expired in a July 2026 state registry check. The company's own site lists MA #12625 and NH #3855, and its BBB profile lists a master plumber registration under that same base number — those are the company's and the directory's claims, not a registry confirmation. Ask which licence covers your job and what its current status is. The right call for a furnace, boiler, water heater or mini-split replacement north of Boston or over the New Hampshire line, with a long trail of customers who came back for a second and third job. Confirm the licence status and get the scope in writing before the truck rolls.