Therm-O-Loc Windows has been building vinyl windows since 1984. We have always used only top-grade virgin vinyl in all of our window frames and sashes. Decades of experience have given Therm-O-Loc the expertise needed to build the highest quality windows on the market today. We are deeply committed to product excellence and customer service, and satisfaction. Today you have many choices in style and quality, and we do our best to give you both. We are always looking for ways to improve our vinyl windows. We strive to practice the Golden Rule by treating You the same way we want others to treat us. Putting this into practice means delivering honest and reliable service. If we say we’ll come out to give you an estimate or install your windows, we will do our best to be there on time. We procure our vinyl from VEKA, a family-owned global supplier of extruded vinyl products. With the standard LoĒ and argon glass package, all our 1000 series Double Hung, Slider, and Picture windows and the 300 series Casement windows meet the ENERGY STAR® requirements.