Direct Answer
To hire a reliable commercial glass & curtain wall installation contractor in Duluth: (1) Get 3 written quotes with line-item breakdowns, (2) Verify MN license at Minnesota Department of Labor (dli.mn.gov), (3) Confirm active general liability and workers' comp insurance, (4) Check Google and BBB reviews specific to Duluth projects, (5) Never pay more than 10-30% upfront — never pay in full before completion.
Full Explanation
Red flags specific to Duluth contractors: no physical Duluth-area address, pressure to start immediately, cash-only payment demands, and license numbers that don't verify at Minnesota Department of Labor (dli.mn.gov). Seasonal demand during summer brings out less reputable contractors.
Local Factors in Duluth
📍Verify license: Minnesota Department of Labor (dli.mn.gov)
📍File complaints: Minnesota Department of Labor (dli.mn.gov)
📍Homeowner protections under MN consumer protection law
📍BBB Greater Duluth chapter for complaints history