Direct Answer
To hire a reliable hvac contractor in Gaithersburg: (1) Get 3 written quotes with line-item breakdowns, (2) Verify MD license at Maryland Home Improvement Commission (dllr.state.md.us), (3) Confirm active general liability and workers' comp insurance, (4) Check Google and BBB reviews specific to Gaithersburg projects, (5) Never pay more than 10-30% upfront — never pay in full before completion.
Full Explanation
Red flags specific to Gaithersburg contractors: no physical Gaithersburg-area address, pressure to start immediately, cash-only payment demands, and license numbers that don't verify at Maryland Home Improvement Commission (dllr.state.md.us). Seasonal demand during summer brings out less reputable contractors.
Local Factors in Gaithersburg
📍Verify license: Maryland Home Improvement Commission (dllr.state.md.us)
📍File complaints: Maryland Home Improvement Commission (dllr.state.md.us)
📍Homeowner protections under MD consumer protection law
📍BBB Greater Gaithersburg chapter for complaints history