The Cool Roofing Materials Database was created in 1998 and may not be current.
We suggest you examine the relative 'coolness' of various types of building materials, to select a type of roofing or roof coating which may meet your needs to reduce air conditioning energy use or to improve comfort. Although a very wide variety of materials are available, most materials fall into a few classes. For example, most white materials have a solar reflectance of 0.65 to 0.85, a high infrared emittance (which is good), and only heat up about 1/5 as much as black materials above air temperature in the midday sun. To take a first look, we have tabulated below the temperature rise in full sun. We have also assumed that there is little wind (wind helps cool the roof). For more details, click on the headings in the main data tables. Keep in mind that this is the temperture rise, not the temperature itself. Thus a temperature rise of 90 degrees on a 100 degree day means the roof temperature peaks at 190 degrees!
| Material | Roof temperature rise above air temperature (degrees F, full sun, no wind) | Remarks |
|---|---|---|
| Bright white smooth materials | 15 F | The coolest construction materials. Can be roof coating, membrane, metal, tile, etc. A soiled white is warmer, about 30 F. |
| Rough white surface | 35 F | Rough surfaces of any given material absorb more sunlight than smooth surfaces |
| Very light (pastel) colors | 15 to 55 F | |
| Intense but not very light colors (green, red, blue, etc.) | 79 to 83 F | Research may identify cooler colors |
| Medium gray | 52 F | Reflectance half way between white and black |
| Aluminum-pigmented asphalt roof coatings | 50 to 65 F | The brightest aluminum coatings are the coolest |
| Built-Up Roof (BUR) covered with gravel | 61 to 83 F | Cooler values obtained with lighter gravel |
| Asphalt shingles and granulated capsheet | 72 to 90 F | The lighter asphalt shingles are cooler, but not much. In particular, even "white" asphalt shingles are hot. |
| Black materials | 90 F |
One you have chosen one or two prospective types of cool roofing materials, it's time to get information directly from contractors or manufacturers regarding the type of work to be done. Some sources of cool roofing materials are listed in our pages; these should be supplemented with your own web search, the yellow pages, etc. Cool roofing materials offer excellent benefits in terms of improved summertime comfort and reduced air conditioning costs. However, as with any construction project, quality, durability, warranty, etc., are overriding considerations. Don't forget to check the references of prospective contractors.