Cool Roofing reflects the sun’s light energy back to the sky instead of allowing it to enter a building as heat. In many climate zones, a cool roof can substantially reduce the cooling load of the building, providing several direct benefits to the building owner and occupants:

  • Increased occupant comfort, especially during hot summer months
  • Reduced air conditioning use, resulting in energy savings typically of 10-30%
  • Decreased roof maintenance costs due to longer roof life
  • Reduced peak demand for electricity, helping to lower costs and avoid power outages

In addition to white, cool color products come in a wide variety of colors (darker-colored pigments) that maintain a high solar reflectance.

  • Built-up Roofing (includes asphalt and coal tar pitch): Built-up Roofing (BUR) consists of built-up layers of asphalt and plies that can be covered with a capsheet (or surfacing material). The cool products found in this category refer to the properties of the capsheet.
  • Metal:  Metal roofs come in a variety of textures and colors, including some darker cool colors with special additives that allow these dark colors to achieve significantly greater reflectance than previous versions of the same product.
  • Modified Bitumen:  Modified bitumen is bitumen (asphalt or tar) modified with plastic and layered with reinforcing materials then topped with a surfacing material.  Like BURs, the radiative properties of modified bitumen (mod bit for short) are determined by the surfacing material.
  • Single-Ply:  Single-ply roofing is a prefabricated sheet of rubber polymers that is laid down in a single layer over a low or steep-sloped roof. The single-ply membrane can be loose-laid and weighted down with ballast or pavers or firmly set on the roof and attached with mechanical fasteners or adhesives.

* Roof coatings can be divided into two categories: field-applied and factory-applied.  Field-applied coatings are applied directly onto the roof surface, either on a new roof assembly or over an existing roof surface (and can be applied over top of just about anything, so long as the right coating is selected). Factory-applied coatings are applied at the factory prior to distribution.
** The two basic characteristics that determine the coolness of a roof are solar reflectance (SR) and thermal emittance (TE). Both properties are rated on a scale from 0 to 1, where 1 is the most reflective or emissive. The CRRC measures these two properties for cool roofing products, both for the product’s initial values and after three years of weather exposure.