Manufactured homes are less energy efficient than site-built homes.
On October 24,1994 a new minimum energy conversation standard became effective. The new energy standards are resulting in lower monthly energy bills, a factor industry officials say will enhance the affordability of manufactured housing and, perhaps, improve mortgage underwriting terms. Improved home ventilation standards have also been adopted in conjunction with the energy standards, a step that will improve indoor air quality and condensation control in manufactured homes.
The new standards rely on computer modeling to identify the optimum cost-effective conservation level for a home located in any one of three regions in the nation. In developing the standards, the U.S. Department of Housing and Urban Development followed Congress mandate to establish standards that "minimize the sum of construction and operating costs" over the life of the home. This emphasis on "lifecycle" energy costs is unique among national energy standards.
A new thermal zone map for manufactured housing identifies three regions: the southeastern states are grouped from South Carolina to Texas in Zone I; the mid-zone of the nation is grouped from North Carolina across to California in Zone II; and the remaining northern part of the country is grouped together in Zone III.
HUD's new standards require that manufactured homes comply with one of three alternative options: design the home's overall thermal efficiency to account for heat loss through the insulted surfaces of the thermal envelope (better known as Uo-values) for three zones; adjust Uo values with credits for high efficiency heating and cooling equipment; or by totally redesigning the home with new innovative technologies that use no more energy than published Uo values. Zone II, including Oklahoma, requires a Uo of 0.096. These efforts are ensuring that manufactured homes remain affordable, not only in start-up costs, but for the life of the home.