VELUX venting Skylight Systems bring fresh air into your home, improving air circulation, ventilation, and air quality. These skylights transform and visually expand a room using natural light from above, and the integrated solar powered shade gives you effortless control over that light. The shade also helps block the sun's heat during the summer and retain your home's heat in the winter, which improves your skylight's energy efficiency up to 45% (depending on model & size.) Deck mount skylights are secured directly to the roof deck, so it's important to know your rough opening size when ordering this type of skylight.