In an effort to further reduce cooling energy and to mitigate urban heat islands, Energy Secretary Steven Chu announced that as of June 1, 2010 roof replacements and roofs for new construction on all DOE buildings shall be cool roofs, unless they are determined to be uneconomical by a life-cycle cost analysis. In addition, new roofs shall have a thermal resistance of at least R-30. This is an update of DOE Order 430.2B “Departmental Energy, Renewable Energy and Transportation Management.” The DOE announced that any questions on cool roof installations and economics may be directed to Mr . Richard Kidd, Director of the Federal Energy Management Program.
In the DOE program both low slope and steep slope cool roofing are defined using solar reflectance and thermal emittance, as measured in accordance with the Cool Roof Rating Council program.. Low slope criteria for cool roofing include a minimum 3-year aged solar reflectance of 0.55 and aged thermal emittance of 0.75. Another option for low slope roofing is a minimum 3-year aged solar reflectance index (SRI) of 64, per ASTM E1980-01. Steep slope cool roofing must have a minimum SRI of 29.