The Building Performance Institute, Inc. (BPI) is pleased to announce that BPI-2400-S-2011: Standardized Qualification of Whole House Energy Savings Estimates Standard, also known as the "Delta Standard", is now available for public comment.

Created by BPI's Standards Technical Committee, the Delta Standard specifies a process for the calculation of standardized estimated savings: the difference (delta) between the modeled energy usage before and after an upgrade using approved building energy use simulation software. The process uses actual home energy bills to estimate savings, and provides a set of standardized operating conditions to be used in the final calculation of estimated savings. The standard applies to residential buildings of 4 units or less.

"The Delta Standard will increase homeowners' confidence in energy savings projected by simulation software used by home performance contractors for homes that undergo energy efficiency retrofits," said Larry Zarker, BPI's CEO. "By using actual utility bills to measure pre-retrofit energy consumption, this approach sets realistic boundaries on estimated savings. This is truly a ground-breaking standard for the home performance industry."

"This standard also provides contractors with an important alternate approach for evaluating savings in homes where monthly utility data is available, but not of reliable quality," said Asa Foss, Chairman of BPI's Standards Technical Committee and a nationally recognized expert in the field of energy conservation.

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