A light-colored roofing sample may attract attention during a commercial reroofing discussion, but appearance alone is not a complete product comparison. Ask the contractor for the exact proposed product and its published thermal ratings, then keep those details with the proposal.
Understand the two properties
The Cool Roof Rating Council explains that solar reflectance and thermal emittance are the two basic properties used to describe a roof’s coolness. Reflectance concerns sunlight reflected by the surface; emittance concerns how efficiently absorbed heat is released. Both are reported on a scale from zero to one.
Cool roofing is not limited to white products. The council notes that some darker pigments can reflect strongly in the near-infrared part of sunlight. Request measured product information instead of relying on color names or a photograph.
Compare ratings at the same stage
The council reports initial ratings and ratings after three years of outdoor exposure. Put the initial figures in one column and the aged figures in another when reviewing options. This avoids comparing a new-product rating from one proposal with an aged rating from another. If a figure is missing or its basis is unclear, ask for clarification before treating the options as equivalent.
Connect the product to the building
A product rating does not tell you the annual savings for your specific property. The Department of Energy’s consumer guide to cool roofs explains that energy and cost results depend on climate and building characteristics. Our article on climate and weather considerations for commercial roofing offers broader context for that discussion.
Ask the project team what assumptions support any savings estimate and whether it considers the building’s actual use. Keep the explanation separate from the product rating so neither is mistaken for the other.
Record the exact selection
Write down the manufacturer, product name, color or finish and the rating information used in the decision. Ask the contractor to identify how the proposed surface fits the complete roof assembly and the project requirements. If the selection changes later, request an updated comparison before approving the substitution.
This small record makes the decision easier to review with the project team. It also provides a useful reference when future maintenance or replacement discussions begin.
