Energy-efficient and environmentally friendly features are very popular in new home construction, according to a recent survey by the National Association of Home Builders (NAHB). Survey results show all 337 respondents said they use at least one green building product or practice. In addition, 95 percent said they use low emissivity (low-e) windows in their projects, which improve a home's efficiency by allowing natural light into the home while reflecting ultraviolet rays. The next most popular item was high-efficiency heating, ventilation, and air conditioning systems, used by 92 percent of respondents. Other often-used items include programmable thermostats, Energy Star appliances, and duct systems designed to minimize leakage. Improvements to a home's thermal envelope, moisture control measures, and energy-efficient construction techniques to minimize the use of materials were all used by 67 percent of builders, while 64 percent said their new homes include water conserving faucets and fixtures, and 51 percent use materials from regional suppliers. The least popular green building products or practices were energy management systems, cited by 11 percent of respondents, passive solar design, and solar water heaters.