This proposal would modify the treatment of cool roofs (primarily roofs with high solar reflectance and high thermal emittance) in California’s Title-24 standards for non-residential (NR) buildings. Under the current standards, cool roofs are a compliance option. Under this proposal, cool roofs will be considered a prescriptive requirement for NR buildings with low-sloped roofs (i.e., roofs with a ratio of rise to run not exceeding 2:12). Prescriptive requirements would not change for NR buildings with high-sloped roofs, high-rise residential buildings, low-rise residential buildings, or guest rooms in hotel/motel buildings.

The proposed measure promotes the use of cool roofs to reduce cooling energy usage and peak electrical power demand in air-conditioned buildings regulated by Title 24. Such buildings include but are not limited to offices, retail stores, health care facilities, schools, universities, and high-tech manufacturing facilities. Prior research has indicated that savings are greatest for buildings located in climates with long cooling seasons and short heating seasons, particularly those buildings that have distribution ducts in the plenum, cool-coatable distribution ducts on the roof, and/or low rates of plenum ventilation.