The energy use implications of design choices in commercial buildings

The Energy Policy Act of 1992 (EPACT) requires that states promulgate energy codes that meet or exceed requirements of ASHRAE/IES Standard 90.1-1989 (1). This paper focuses on energy savings achieved by these code changes, through daylighting measures. A recently constructed retail building that does not meet the new standard is used as a basis to evaluate potential energy savings. TRNSYS computer simulations were used to estimate the energy use in the building. Building and equipment models were created using information from plans, site visits and interviews with occupants. The models were validated using monthly energy bills. The economic savings due to daylighting were found to be as great as savings associated with building envelope changes. Envelope changes primarily decreased heating loads in the building. Daylighting realized energy savings both in decreased consumption for lighting equipment and through the decreased cooling loads experienced by the air-conditioning system.