How to Build a Zero Electric Utility Cost House

Jeff Christian, Oak Ridge National Laboratory

Keywords

Abstract

The construction methods, building products, appliances and equipment of four single-family houses that achieve dramatic energy reductions and approach “net zero energy” use are presented. A 30-50 sensor data acquisition system constantly measures performance characteristics of each house. This data is used to develop guidelines for building a zero energy cost house. The energy performance of the test houses are compared with a “base house” — same size and location, but without advanced features of “net-zero-energy” houses. The data show the houses used about 50% less energy from the grid than the base house. Energy costs per day for these all electric houses were $1.01 for ZEH1, $0.88 for ZEH2, $0.79 for ZEH3, and $0.75 for ZEH4. These costs are based on an electric rate of $0.068/kWh and utility credit of $0.15/kWh for all solar AC power produced by the houses. The percentage of total energy load supplied by the PV systems for these houses ranged from 20% to 27%. The four near-zero-energy houses were built to demonstrate the feasibility of making net-zero-energy housing affordable. The houses, built between 2002 and 2004, have construction costs of about $100,000, including the cost of the rooftop solar PV systems. These houses can be assembled by workers with limited skills making them ideal for rebuilding on a large scale after man made or natural disasters.