Sri Roof Rating

Solar reflective index sri is important to understand when selecting a highly reflective roof coating that will help lower energy cooling costs.

Sri roof rating.

Asphalt shingle products with an energy star rating do not utilize the sri compliance path. These ratings are presented below. Recycled content of berridge metal. Solar reflectance index sri.

Solar reflectance is the amount of solar energy or uv rays that is reflected away from the building back into the atmosphere. The sri is a calculation method using solar reflectance and thermal emittance values to determine the roof s overall capacity to refuse solar heat. These shingles must have an initial solar reflectance of at least 0 25 and a three year solar reflectance measurement of at least 0 15. Does having a cool roof help with the r value of roof assembly.

Leed 2 2 sustainable sites credit 7 2 states that to receive one point building owners should use a roof with a solar reflective index sri of 78 over at least 75 percent of the roof s surface for roofs with slopes less than 2 12. Higher sri ratings for shingles mean greater reduction in cooling load on a home. Sri measures the roof s ability to reject solar heat defined such that a standard black reflectance 0 05 emittance 0 90 is 0 and a standard white reflectance 0 80 emittance 0 90 is 100. In addition to a description of what they like and dislike about their shingles homeowners also rate their satisfaction from 5 very satisfied to 1 very unsatisfied.

Peter l posted in energy efficiency and durability on april 12 2015 09 40am if a cool roof design has a sri of 40 would going for a sri of 54 make that much more of a difference. In fact this is fairly is common for highly reflective products with high emissivity for example light colored asphaltic membranes like gaf energycap. To meet leed requirements a roofing material must have a sri of 29 or higher for steep slope 2 12 roofing and a sri value of 78 or higher for low slope roofing. Numbers from 20 to 90 are typical but it s interesting to note that sri can be more than 100.

The shingles with the highest level of satisfaction appear first lower levels come later in the list. Incorporates both solar reflectance and thermal emissivity in a single value. Asphalt roofing shingles with higher sri ratings are cooler in the sunshine. According to the manufacturer they quote ornl as saying it does help.