Last week, the Zero Net Energy (ZNE) house was unveiled in Clovis, California. The three-bedroom, two-bathroom home has a living area of 2,064 square-feet and was built as a join effort between BIRAenergy Consulting and De Young Properties. Pacific Gas and Electric (PG&E) offered technical assistance to the builders in trying to find ways of getting the home to use only one-third of the energy needed for a house built to minimum code. ZNE House was built to become a model for future net zero homes in the area.
The house features numerous energy-efficiency improvements, which are in accordance with California’s Long-Term Energy Efficiency Strategic Plan. This plan stipulates that all new residential construction in California will be net-zero by the year 2020. The house will not be made available for purchase yet, as it will serve as a prototype to study how well it functions and what improvements have yet to be made.
The ZNE House features a 5.88 kW rooftop solar photovoltaic system designed to supply all the needed power to the home. The house also features a highly efficient heating and cooling system, while the household water is heated by a Rheem Hybrid Heat Pump water heater. This heater works by harvesting heat from the air around it and transfers this heat into the water of its tank. Normally, heat pump water heaters can be two to three times more energy efficient than conventional water heaters, but they only work in locations that remain in the 40º–90ºF (4.4º–32.2ºC) range in all seasons, and which have at least 1,000 cubic feet (28.3 cubic meters) of air space around the water heater.
The ZNE house is fitted with dual-pane, triple-layer, argon gas-filled Energy Star-qualified windows, and has an electric vehicle charging station in the garage. The roof is covered with roof tiles that defer sunlight and heat away from the home, which is a necessary feature to keep the cooling costs and energy expenditure low during the hot summers in California. The house also has custom designed ducts that are buried underneath the attic insulation so air is not passing through a warm environment before being cooled. The lighting throughout the house is 100 % LED lighting. The home also features a two-stage, 95-percent efficient Lennox furnace and an air conditioner rated at a high 19 SEER and 14 EER.
The builders have not revealed the final cost of buying this type of home, though they did stipulate it would cost more than a traditional home. The higher price would, of course, be offset by the low monthly costs associated with living in a net-zero home.