In July 2008, SB 1141 (known as the Energy-Efficient Manufactured Homes Incentive Program) was enacted, which amended the sales tax cap to provide for a full sales tax exemption for manufactured homes purchased between July 1, 2009, and July 1, 2019, if the home has been designated by the U.S. Environmental Protection Agency and the U.S. Department of Energy as meeting or exceeding each agency's energy saving efficiency requirements or has been designated as meeting or exceeding such requirements under the federal Energy Star program.
Homes that do not meet Energy Star standards but still meet certain state standards may qualify for a $300 sales cap. Efficiency standards include: storm or double-pane glass windows, insulated or storm doors; and a minimum thermal resistance (R) rating of the insulation of R-11 for walls, R-19 for floors and R-30 for ceilings. Variations of these ratings are accepted if the total heat loss for the home does not exceed that calculated using the levels of R-11 for walls, R-19 for floors and R-30 for ceilings. The current edition of the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) guide is used to determine heat-loss calculation.