The requirements for the credit call for an emmissivity of "at least 0.9." We have used a metal roofing product that is energy star rated but has an emmissivity of 0.85. Because there is no standard referenced for the emmissivity requirement, we cannot tell if it is unreasonable to round the 0.85 value up (since the credit requirement is set at one decimal position). Furthermore, we are questioning if a range of emmissivity values is more appropriate in response to climatic differences. This roofing material achieved this credit under the 1.0 rating system. Under a strict interpretation of the requirement, metal roofing products can no longer achieve the credit. Please let us know if the product we have selected is able to achieve this credit.
The TAG Committee ruled that the LEED language requires an emmissivity of "AT LEAST" 0.9; therefore rounding up from a lower value is not allowed.