The Ranking
Our top 8 window companies in Denver
Denver's housing stock gives window and door companies a mix of jobs. Bungalows, Denver squares and Victorians in older neighborhoods often have original wood windows that rattle in the wind, while postwar ranches and 1970s homes tend to carry thin aluminum or early vinyl units that leak heat. Newer builds usually need patio doors, large picture windows or hail-damaged replacements. Homes in Denver's landmark and historic districts may need design review before windows change, so ask your installer and the city before you order.\n\nThe climate does most of the damage. At a mile above sea level, the sun is intense and fades interiors through clear glass, hail can crack glass and dent frames, and wide temperature swings stress seals, which is why fogged double-pane units are common. Energy costs make the glass package matter. Ask for the NFRC label, which lists the U-factor and solar heat gain coefficient for each window, and look for Energy Star certification. A lower U-factor holds heat in during winter, and a lower solar heat gain helps on west-facing walls in summer.\n\nHomes built before 1978 may have lead paint on old window frames. Under the EPA's Renovation, Repair and Painting rule, a company that disturbs that paint should be an EPA lead-safe certified firm, so ask for the certificate number. Colorado has no state licence for window installers, so the checks are different. Look up the company's registration with the Colorado Secretary of State, ask for a certificate of liability insurance, and ask whether your project needs a permit from Denver Community Planning and Development. Changing the size of an opening usually does.\n\nThis list starts from Google Maps searches for window replacement, windows and doors companies, and entry door and patio door installation in Denver, merged in Google's order and checked against each company's own website. We kept companies with a street address in Denver, a working site, a real logo, at least 4.5 stars and at least 50 Google reviews, and dropped big-box stores, glass repair shops, commercial glazing contractors, suburban offices and sites we could not verify. A few national brand locations could not be checked because their sites blocked automated reading, so they are not listed. Ratings were read on November 3, 2026. Get two written quotes that name the brand, series and glass package for every opening, plus the warranty terms and the installation crew.
