Resources

ASTM E1918 precision and bias test instructional video

The Heat Island Group demonstrates how to measure solar reflectance using a pyranometer and an albedometer, in accordance with ASTM E1918 precision and bias test.

ASTM E1918 precision & bias test instructional video, 2012-06-15

Car Shell Reflectance Database

This Microsoft Access database file contains specifications of a multitude of car shell products from various manufacturers around the world. 

DOE Cool Roof Calculator

The DOE Cool Roof Calculator was developed by the U.S. Department of Energy's Oak Ridge National Laboratory (Version 1.2). This version of the calculator is for small and medium-sized facilities that purchase electricity without a demand charge based on peak monthly load. If you have a large facility that purchases electricity with a demand charge, run the CoolCalcPeak version in order to include the savings in peak demand charges from using solar radiation control.

Interactive Rooftop Reflectance Map

An interactive and comparative map of roof reflectance for 5 California cities (Los Angeles, San Francisco, San Jose, Bakersfield and Long Beach). This was completed as part of a study by Lawrence Berkeley National Laboratory (Berkeley Lab) for the California Air Resources Board.

Read more about the map here. 

LBNL Pigment Database

The Lawrence Berkeley National Laboratory Pigment Database describes the solar spectral radiative properties of conventional and cool pigmented coatings.

Mean Solar Irradiance Ratio: Winter to Summer

This map illustrates the ratio of mean global horizontal solar irradiance in the winter to that in summer throughout the U.S. The northern mainland U.S. (latitude >= 40N) receives 3 to 5 times as much daily sunlight in summer than in winter, whereas the southern U.S. receives relatively more constant levels of sunlight throughout the year. Map © 2009 Ronnen Levinson, Lawrence Berkeley National Laboratory; based on NREL TMY2 weatherfiles.

Roof Savings Calculator (RSC)

The Roof Savings Calculator was developed as an industry-consensus roof savings calculator for commercial and residential buildings using whole-building energy simulations. It is built upon the DOE-2.1E engine for fast energy simulation and integrates AtticSim for advanced modeling of modern attic and cool roofing technologies. An annual simulation of hour-by-hour performance is calculated for the building properties provided based on weather data for the selected location. Annual energy savings reported are based upon heating and cooling loads and thus this calculator is only relevant to buildings with a heating and/or cooling unit.

SRI Calculator

One way to measure how "cool" a roof can be is by calculating its Solar Reflectance Index (SRI). This index is calculated following ASTM Standard E1980-11 using a roof product's solar reflectance and thermal emittance values. The SRI calculation can also be used to estimate the surface temperature of the roof product under prescribed conditions. High SRI values indicate "cooler" roofing products. To calculate SRI, download the SRI Calculator and enter the solar reflectance value (R) and the thermal emittance value (E) as decimals, then click on "Update SRI". Note: macros must be enabled in Excel.