Improvements in energy efficiency can significantly reduce the annual growth in greenhouse gas emissions. Such improvements occur when energy intensity is reduced; no reduction in energy services is required. Using the concept of ‘‘cost of conserved energy’’ to develop conservation supply curves similar to resource supply curves, researchers consistently find that electricity and natural gas savings of nearly 50% of current consumption are possible for U.S. buildings. Such reductions in energy consumption directly reduce emissions of greenhouse gases.To capture these savings, we must continue to develop energy‐efficient technologies and strategies. This paper describes three recent energy‐efficient technologies that benefitted from energy conservation research and development (R&D) funding: high‐frequency ballasts, compact fluorescent lamps, and low‐emissivity windows. Other advanced technologies and strategies of spectrally selective windows, superwindows, electrochromic windows, advanced insulation, low‐flow showerheads, improved recessed lamp fixtures, whitening surfaces and planting urban trees, daylighting, and thermal energy storage are also discussed.