National Renewable Energy Laboratory

Buildings Research

Zero Energy Homes Research

Our award-winning building scientists and engineers use integrated building designs and processes to create homes that produce as much energy as they consume. These homes use alternative construction systems, high efficiency products, and renewable energy to yield a zero net-energy home where utility bills are no longer a concern. To learn more about zero energy homes and our related research, visit one of the links below.

A Modest Zero Energy Home

Below is an illustration of a modest zero energy home. Move your curser over the letters below for more details and illustrations. Learn more about affordable zero energy homes and our work with DOE's Building America Program by visiting their Affordable Housing Web page. We also published a technical report called A Cold Climate Case Study for Affordable Zero Energy Homes (PDF 648 KB). Download Adobe Reader.

Flash animation text alternative: An illustration of a zero energy home highlighting the following energy efficient features: EnergyStar appliances in the kitchen and utility room, light-colored roof shingles and increased attic ventilation to reduce attic overheating, 100% compact fluorescent lighting, small thermostatically controlled electric baseboard and ductless direct-vent natural gas space heaters, an energy recovery ventilation system with ducting inside the conditioned space, a superinsulated building envelope, a solar water heating system, a 4-kW, grid-tied solar electric system, and passive solar windows.

A: Fresh Air Ventilation System

  • Energy Recovery Ventilation (ERV) system with ducting inside conditioned space
  • ERV is equipped with high efficiency ECM motors

B: Superinsulated Building Envelope

  • Double stud wall construction, overall wall thickness = 1 foot
  • Air tight with continuous air and vapor barrier
  • Fiberglass insulation: R-40 walls, R-60 ceiling, R-30 floor
  • Air tight outlets in exterior walls
  • Raised heel trusses provide space for ceiling insulation

C: Passive Solar Tempered Windows

  • Expanded southern window area with summer shading overhangs
  • Orientation specific glazing:
    • high solar heat gain coefficient on the South (SHGC = 0.58)
    • low solar heat gain coefficient on West, North, and East (SHGC = 0.27)
  • Reduced east and west, and north window area
  • Low-e windows throughout

D: Other Energy Efficient Features

  • EnergyStar appliances in kitchen and utility room
  • All mechanical equipment is within the conditioned space
  • Light-colored roofing shingles and increased attic ventilation reduces attic overheating
  • 100% compact fluorescent lighting used.

E: 4-kW Photovoltaic System

  • Grid-tied with net metering - no batteries
  • Sized to meet all electrical loads annually and offset natural gas use.

D: Simple Space Heating System

  • Small thermostatically controlled electric baseboard heaters in each bedroom
  • Thermostatically controlled ductless direct vent natural gas space heater in the living/dining room

F: Solar Water Heating with Efficient Back-up Heater

  • Drainback system designed for high Solar Savings Fraction
  • 96 sq. ft of collectors on roof with 200 gallon thermal storage tank in the utility room
  • Back-up water heating from high efficiency tankless water heater