Panasonic FV-04VE1 WhisperComfort&trade; Spot ERV Ceiling Insert Ventilator with Balanced Ventilation and Patent-Pending Capillary Core Offers a revolutionary way to provide balanced ventilation with a ceiling insert ERV Supplies fresh air to replace exhausted air helping to balance air pressure within the home Uses two 4-Inch ducts, one duct to exhaust stale air and the other to supply fresh air from outdoors Continuous run ensures chemicals and other pollutants from cleaning fluids and building materials are vented out and replaced with fresh air Rated 40 cubic feet per minute. Heating %: 66% at 30 CFM, Cooling %: 36% at 29 CFM