A sliding patio door does double duty — it floods your living space with natural light and gives you an easy, wide-open connection to your backyard or deck. At GT Doors, we supply and install energy-efficient sliding doors designed to perform through Ontario's full range of weather, from summer heat to winter cold. Our patio doors feature durable frames, weather-sealed tracks for smooth operation year after year, and glass options that help reduce energy loss — so your new door looks great and helps lower heating and cooling costs. As with all our installations, every sliding door project starts with a free in-home measurement and quote, so you know exactly what to expect before any work begins. We install throughout Whitby, Ajax, Oshawa, Pickering, and the wider Durham Region.