“The work comes from a team at the Lawrence Berkeley National Laboratory in California that’s dedicated to studying how to keep cities cooler. Although team members knew both white and green roofs are better than traditional roofing, they wanted to get some hard numbers comparing the two. White roofs came out ahead in both improving global temperatures and cost, but both are good choices, the team wrote in a paper published in the journal Energy and Buildings.”
Most importantly don’t forget to ensure that your roof is adequately airsealed, insulated and flashing is installed properly to reduce conductive, convective heat gain/loss as well as prevent moisture infiltration. If the building lacks insulation (especially if it has a vented roof cavity) and has unsealed top plates, pipe penetrations, fan roof curb penetrations, etc this should be upgraded first before working on the roof membrane. You may find you have an oversized heating or cooling system after buttoning up the building’s envelope.
Read more: Cooler Ciites