Ventilation-energy liabilities in US dwellings.

The role of ventilation in the housing stack is to provide fresh air and to dilute internally-generated pollutants in order to assure adequate indoor air quality. Providing this ventilation service requires energy either directly for moving the air or indirectly for conditioning the outdoor air for thermal comfort. Different kinds of ventilation systems have different energy requirements. Existing dwellings in the United States are ventilated primatiy through leaks in the building shell (i.e., infiltration) rather than by mechanical ventilation systems. The purpose of this report is to ascertain, ftom best available data, the energy liability associated with providing the current levels of ventilation and to estimate the energy savings or penalties associated with tightening or loosening the building envelope. Various ASHRAE Standards (e.g., 62,119, and 136) are used to determine acceptable ventilation levels and energy requirements. Building characteristics, energy use, and building tightness data are combined to estimate both the energy liabilities of ventilation and its dependance on building stock dwacteristics. The average annual ventilation energy use for a typical dwelling is about 46 GJ (roughly 50% of total energy usage); the cost-effective savings potential is about 28 GJ. The associated total annual ventilation energy use for the residential stock is about 3 ET (ExaToules).