This case study focuses on an all-electric, 2400 ft2 single-story home in Olympia, WA. Building America Industrialized Housing Partnership (BAIHP) staff has provided technical assistance in the design, commissioning, and monitoring phases of the project. This home includes numerous energy-efficiency envelope measures, including a 4.5 kW photovoltaic array (an additional
2.5 kW installed in 2008), ground-source heat pump supplying domestic hot water and space heat to a radiant slab, and solar sunspace. This paper presents modeled and measured overall home energy performance, and an evaluation of building envelope, space and water heating, ventilation, and PV systems.

Home construction began in summer of 2005, and completed field testing and commissioning in May of 2006; a data acquisition system was installed in 2007, which has since been monitoring home energy use.

The home’s US Department of Energy (DOE) Building America benchmark is roughly 52% to 68% whole-house site savings without and with PV. The home’s modeled total electric use is 11481 kWh/year without PV, and 7691 kWh/year net with PV. Monitored total electric use for 2008 and 2009 averages 12845 kWh/year without PV and 6740 kWh/year net with PV; of
PV production, roughly 47% was used by the house, 53% returned to the utility.