Chapter 01 · Climate & transitionEnergy & Transition
Cool roof
Definition
A cool roof is made of materials with high solar reflectance and high thermal emittance, so it stays substantially cooler in the sun than a conventional roof. Benefits documented by Lawrence Berkeley National Laboratory include lower cooling energy use and bills, improved indoor comfort in unconditioned buildings, extended roof service life, and reduced urban heat-island effects at neighbourhood scale.
References
benefits and performance basis
Overview
What it means
One of the cheapest passive measures for cutting cooling loads in hot climates, achievable with coatings, membranes, tiles or metal products.
How it is used
Building codes and voluntary programmes rate roofs by solar reflectance and thermal emittance (e. g. Cool Roof Rating Council ratings); cool roofs are common in green-building certifications and heat-action plans.
Why it matters
Cooling demand is the fastest-growing end use of electricity in buildings; cool roofs reduce peak demand, emissions and heat stress simultaneously.