Big L Windows & Doors in Buffalo, NY offers replacement windows and doors for homeowners and builders. Get a free estimate on your next home project today! Our customers turn to us for all of their home window replacement and patio door replacement projects. Our products, which include Marvin, Therma-Tru, Infinity by Marvin, and ProVia feature a "no call-back" quality, so you are guaranteed an outstanding experience. We service the Western New York area, specifically Greater Buffalo and Niagara Falls, including, Erie County, Niagara County, Chautauqua County, Wyoming County and Orleans County.