Present home energy retrofit programs do not account for the effect of retrofits on indoor environmental quality conditions that influence comfort and health. This project developed a systematic procedure for selecting packages of retrofits that have the potential to simultaneously save energy and improve indoor environmental conditions in apartments. The procedure was used to select retrofits for 16 apartments and the resulting changes in indoor environmental conditions and apartment energy use were assessed. Implementation of the retrofits resulted in overall, but not universal, improvements in indoor environmental quality conditions. Ideally, the project would have provided unambiguous evidence of simultaneous energy savings. However, based on the large year-to-year changes in energy use in non-retrofit control apartments, the study was too small for accurate measurement of energy savings. Communication of study methods and results to utilities, policy makers, and owners and managers of subsidized multifamily housing has raised awareness of the opportunity to simultaneously save energy and improve comfort and indoor air quality when apartments are retrofit.