Cost/Benefit Analysis for Cool Roofs

We’re doing a remodeling project which includes installing a new roof. Here in California, we get a lot of sun, so the impact of solar irradiance on solar heat gain is a major concern — either for A/C costs (and thus peak summer energy loads) or on comfort (for those of us who don’t have A/C). Thus, I’ve been looking into solar reflectivity and what has been called the “cool roofs“ movement. There is the Cool Roof Rating Council, “created in 1998 to develop accurate and credible methods for evaluating and labeling the solar reflectance and thermal emittance (radiative properties) of roofing products and to disseminate the information to all interested parties.”