LBNL Report Number
Measured data on the energy savings and cost-effectiveness of conservation measures and practices installed in existing multifamily buildings are compiled and analyzed for over 100 buildings. Factors that explain the range in energy savings are analyzed including energy use before the retrofit, the level of investment, and choice of measures.Energy savings achieved are typically 10 to 25 percent of pre-retrofit energy use although large variations are observed in energy savings and in costs per unit of energy saved. The median retrofit investment in multifamily buildings is approximately $530 per unit. Many conservation investments are attractive investments from a building owner's perspective: the median real rate of return for buildings in this study is 22 percent. Preliminary results also suggest that some envelope measures (e.g., "shell" packages and window measures) have longer payback periods than many of the heating system retrofit strategies.