The test house is a double-wide manufactured home built to the HUD standard that applies nationwide to manufactured homes. It has three bedrooms, two baths, a kitchen, and a family, dining and living area. The house has a floor area of 140 m2 and a volume of 340 m3.The exterior construction consists of insulated wood-frame walls, with exterior vinyl siding and an interior finish of vinyl covered drywall without taped and textured joints, as well as a vapor retarder in the walls, ceiling and floor. The house's heating, ventilating and air-conditioning system consists of a 22 kW gas furnace, a 15 kW air conditioner, and a forced air re-circulation fan with a design airflow rate of 470 L/s. In addition there are whole house, kitchen, and two bathroom exhaust fans in the house. There are several options for ventilating the house. One option is simply to rely on envelope infiltration driven by the wind and indoor-outdoor temperature differences, as is done in most single-family dwellings. Infiltration may be supplemented by periodic operation of local exhaust fans in the bathrooms and kitchen. The house can also be ventilated through an outdoor air intake duct on the return of the forced air fan, which draws in outdoor air whenever the fan is operating. This fan can operate either continuously or by thermostat control. In addition, the whole house exhaust fan can be operated with or without passive window vents open.