Building an Everyday Near-Zero Energy HomeSeveral technologies come together to build an affordable and sustainable home.

  • By Joe Nasvik

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Saving Energy

Armstrong says that reducing the energy requirements involved every aspect of the construction. Using products with good R-values is important, as is building structures with good “thermal efficiency” ratings. Thermal efficiency is a key factor in the energy equation. It's a measure of how tight a structure is. If air can easily move through a structure, its thermal efficiency is very good.

Thermal efficiency is measured by the Home Energy Rating System (HERS)—which is a way to quantify how much air can move through a structure. Partly, the number is arrived at by performing what's commonly referred to as a “blower door test”. By placing a fan at the primary entrance of a building and sealing the space around the fan, the tightness of the structure can be assessed.

Below: Inside the home the ICF walls were covered with drywall, as were the SIPS panels. The concrete floor installed over EPS panels has radiant floor heating tubes in the concrete. The tile floor is better than carpet for heat transfer. Photo: American Polysteel

The HERS score for this home was 94.5 out of a possible 100 points. (With 100 being the best score at the time this house was built.) Chrisner thinks this score is possibly the highest (best) score in the country for a house. ICF walls provide good R-values and thermal efficiency numbers. Although both ICF and SIPS walls are excellent systems for saving energy, there are other factors that also are important. These include:

  • The insulation in ceilings and roofs
  • Energy-saving glass in windows and the tightness of the seal between the window and its frame, as well as the space between the frame and the wall

    • Before the standing seam steel roof panels were installed, workers attached thin photovoltaic sheets that send electricity to an inverter, which stored the power in batteries for use in the home. Water circulating in tubes just below the metal is heated by the sun to further save on energy costs. Photo: American Polysteel

  • The seals between doors and their frame, and between frames and walls
  • The efficiency of the HVAC system

    • In order to further reduce the external energy requirements for this house, there are two interesting features. Just below the standing seam roof panels there are coils circulating water that can be heated from the sun in order to reduce the energy needed to heat water. Up to 4 kilowatts of hot water will be supplied this way. Also, on the top of the metal roof panels are thin photovoltaic sheets that will produce 2½ kilowatts of power.

    Why This House Is Important

    Articles about concrete homes built in the United States usually cover high-end, more expensive homes. This home represents the other end of the scale—it's affordable, operating costs will be manageable, and every attempt is being made to keep its “carbon footprint” very low.

    Also important is the developing technology to provide buildings that can survive high-impact weather events, fire, mold and fungus, and pests, while using less energy.

    This is only one home but the lessons learned already are being used to plan a much larger revitalization project in Philadelphia—400 homes either rehabilitated or replaced with new construction.

    Organizations contributing to this project:

    The Institute for Business & Home Safety, Tampa, Fla. Developer of the Fortified...for safer living program

    The Partnership for Advancing Technology in Housing (PATH)

    The U.S Green Building Council, Washington, D.C. Developer of the LEED program

    Project Participants:

    Owner: St. Michael's Housing Corp., Paterson, N.J.

    Organizer: BASF, Florham Park, N.J.

    Architect: GRAD Associates, Newark, N.J.,

    Green Building Consultant: Chrisner Group, Hamilton, N.J.

    Builder: KBI, Edison, N.J.

    ICF Supplier: Polysteel, Albuquerque, N.M.

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