- Vents attics up to 2300 square feet. - Automatic thermostat. - Patented ring design makes the fan more efficient and quieter than traditional fans. - Reduce heat and moisture in you attic. - Help protect your roof, cooler shingles last longer. - Saves energy costs - Dimensions: 17 3/4 Inch Length, 17 3/8 Inch Width, 4 Inch Depth - Reduce air conditioning costs. - Help control ice build-up on roofs during winter.