GreenPoint Rated Climate Calculator

RAEL conducted a study on Build It Green’s GreenPoint Rated* (GPR) Climate Calculator, reevaluating the assumptions and calculations of the first version of the calculator to improve the accuracy of the results. The calculator estimates the direct and embedded greenhouse gas emissions of home construction and renovation in California from home size, occupancy, appliances, energy and water use, landscape (shade trees), refrigerant leakages, and materials. The lab updated calculations based on Title 24 and new CALGreen building codes, revised assumptions and the formulas that depended on them, and added more detailed information about water usage and materials such as flooring and roofing. In general, emissions from houses in Northern California increased and those from Southern Californian homes decreased as a result of these changes.

The calculator is already a standard tool in the housing industry, and the lab was able to improve the calculations produced by the calculator with the hope that the results from the calculator can help the development of other tools and programs. Additionally, the calculator now can provide a more accurate view of emissions from Californian homes. Although the tool is not directly usable for other states, the principles and assumptions can be adapted for other regions. Of course, there are still many areas in which the calculator can be improved, but it will continue to be updated and revised as more information becomes available.

*For more about GPR, check out my building certification schemes post .