Zero Net Energy Production Builder Demonstration: Loomis Monitoring Report

Under the auspices of PG&E’s Zero Net Energy (ZNE) Production Builder Demonstration, Blu Homes built a 1,877 square foot all electric ZNE home in Loomis, CA. This report describes the results from monitoring the occupied home for a full year.

The ZNE definition used for the design was based on Time Dependent Valuation (TDV) of energy, and the home met ZNE design requirements. However, TDV cannot be calculated from measured data. Therefore, this report assesses the ZNE performance of the home, based on site energy, and by comparing monitored site energy to modeled site energy. It was not expected that the project would achieve net zero site energy. Actual site energy use was compared to two models: one using the Typical Meteorological Year (TMY) and the other using the Actual Meteorological Year (AMY) for Auburn, California during the monitoring period. Total monitored site energy use was 23% and 29% more than modeled projections using the TMY and AMY, respectively. Actual solar production was 6% greater than TMY modeled solar production, but 10% less than AMY modeled projections. Total PV production offset 71.5% of total site energy consumption, slightly less than the 83% offset predicted by the TMY model.

Heat pump water heater energy consumption (for both domestic hot water and radiant floor heating) was the largest end use at 40.9% of house annual usage. Cooling, plug loads, and non-cooking appliances represent the next largest energy end uses at 15.3%, 14.8%, and 11.9% of total annual energy consumption, respectively.

Five ZNE homes were designed and constructed in this Emerging Technologies project. The first set of reports detailed the design and construction process of a ZNE home built by Habitat for Humanity of San Joaquin County. They can be found here at the ETCC website: Link

In addition to this site in Loomis, below are links to monitoring reports for four other sites in the production builder demonstration project.

A combined report for all 6 projects can be found here: link