Many critical factors have to come together for a successful grow room. The Active Air 4-Inch In-Line Fan is an ideal tool to make sure one of those factors -- ventilation – helps ensure successful growth of your plants. An exhaust/intake fan is essential to get rid of odors and help with temperature control, creating a healthy growing environment for your indoor plants. Calculating the fan capacity your grow room needs takes in many factors, including the climate where you live, the stage of growth your plants are in, and, critically, the type of grow lights you're using. HID and HPS light bulbs use lots of energy and emit quite a bit of heat, so a stronger in-line fan may be needed. LED and fluorescent lights, on the other hand, put out less heat. As a general rule, you want a fan that exchanges the grow room's air at least once per minute this Active Air fan has a capacity of 165 cubic feet per minute. Active Air fans are known for their quiet operation. They have a thermally protected AC motor, as well as a ceramic coating that helps prevent rust and degradation of the metal. They also come with all the needed mountain brackets and hardware you'll need to install them. These fans do not include a built-in speed adjuster, but one can be purchased separately it can make the fan even quieter and more efficient. This in-line fan can be adapted to other ventilation uses, too, including in bathrooms, attics, and just about anywhere you need to move some air. Active Air is part of Hydrofarm. Active Air products include filters, fans, CO2 systems, air conditioners, and dehumidifiers.