Trapped heat and moisture in one's attic not only diminishes the comfort of one's home environment, but they also reduce the life expectancy of your entire roof. This product is an ideal ventilation choice for your home, garage, storage shed, garden shed, utility shed, greenhouse and even your dog house. CONTENTS INCLUDE: The Solar RoofBlaster Fan (patent-pending) comes pre-installed on a galvanized 8" metal can roof vent with flashing (16.5"x16.5"). A 3W solar panel will be attached to the top of the vent hood by four unique, stainless steel clips and is wired to a two-ball bearing, 2700rpm, 39cfm fan that is rated for 50,000 hours. Unlike the plastic vents of many other products on the market, this metal vent is designed to last on a lifetime roof. Plastic will fade and become brittle over time especially on top of a hot roof. INSTALLATION: Install the vent as you would any roof vent - remembering to always vent to code. This product does not allow you to install less vents. Its benefit is to boost the effectiveness of your passive roof ventilation system with the power of the sun! HOW MANY FANS SHOULD I ORDER FOR MY ROOF? We recommend 1 for every 600 sf of roof area. A typical home (1200sf) would take 3-5 vents. It is crucial that a home's attic is ventilated uniformly across the entire attic space. That is why most homes have numerous passive vents or ridge venting installed. BENEFITS: The idea is that cool air will come in from the eave's soffit vents and run along the entire roof deck to escape at the top through the passive vents. This uniform air movement helps keep your roof's deck (the plywood, the trusses, and the rafters) dry & moisture free. It also helps keep your insulation's r-value from decreasing due to condensation dripping down from the roof deck. DOES THIS FAN INCLUDE A THERMOSTAT OR ON/OFF SWITCH? No, not needed. Ideally, the fan should run in summer, to remove excessive heat, and winter, to remove moisture due to condensation.