Electric-powered attic vents use a thermostat to fight heat and a humidistat control ("All Season" model only) to help prevent moisture buildup inside the attic. Featuring a low-profile dome, the power attic vent is unobtrusive when installed on the roof face slanting away from the front of your home. It's an efficient option to replace wind turbines or roof pots already in place. The All Season™ model combines automatic thermostat and humidistat to protect attics from excess heat and humidity year-round. Roof-mount power attic ventilators are available in several CFM capacities and dome colors that blend with the color of your roof shingles. ASRHPBR Roof mounted power attic ventilator Brown 25" diameter metal dome 1500 cfm Ventilates up to 2100 sqft Adjustable thermostat from 60 to 120 degrees & adjustable humidistat from 20% to 90% Thermostat runs fan in summer, humidistat runs fan in winter 4.3 amp motor 6 bladed fan blade 14-1/2" diameter opening Needs 720 sqin of net free intake area. WARNING: Cancer and Reproductive Harm.- www.p65Warnings.ca.gov