Courtesy of U.S. Dept. of Energy
Here at Attainable Home, we like to challenge the idea that truly green, net-zero construction is too expensive for most people who are building a new home. Back in 2016, Habitat for Humanity in Catawba, N.C., proved that the Department of Energy’s Zero-Energy Ready Home standards are quite attainable. They built an affordable home that is so energy-efficient, the utility bills are a fraction of what most people pay—even though the lot they built on isn’t situated well to take advantage of solar energy.
The home was designed by Tightlines Designs of Raleigh. It’s a 1,340 square foot bungalow with an open floor plan and lots of natural light from the plentiful windows.
A History of Efficiency
In fact, the first net-zero home in the state of North Carolina was built in 2005 by a partnership between Habitat for Humanity of Catawba Valley and Appalachian State University. SystemVision, an energy efficiency program for affordable housing run by Advanced Energy and North Carolina Housing Finance Agency, also works with Habitat for Humanity on their award-winning energy efficient projects.
“We measure success by the number of families that we serve with sustainable, affordable homes,” Derek Ross, Construction Supervisor for Catawba Valley Habitat for Humanity, says. “We also find that building ZERH certified homes is meaningful to our board members, donors, and volunteers. The biggest reward is building a home that is not only affordable to purchase, but also affordable to own and operate.”
The Bottom Line
The added construction cost? Around $6,000. The utility savings alone should pay for the difference within about seven years.
While most homes newly built to code will have a HERS index (Home Energy Rating System) rating of 80-100 (and most existing homes score well above 100), this home scores 44 (again, without the benefit of solar energy).
The Energy-Saving Details
Energy efficient construction methods and materials used:
- Insulated corners
- Insulated headers over windows and doors
- More space for insulation at intersections of interior and exterior walls
- R-15 blown-in fiberglass insulation covered with sheathing, sheathing covered with R-10 XPS foam
- Continuous XPS barrier/thermal break
- Air gap between insulation and siding
- R-50 blown-in fiberglass insulation in attic
- 2-foot overhang above windows and doors
- OSB roof sheathing with taped seams
- Crawl space walls lined with XPS R-10 foam
- Energy Star appliances
- Mini-split heat pump in the insulated crawl space
- Heat-pump water heater
- LED light fixtures and energy-star ceiling fans
An Emphasis on Health
Additional features help make the home a healthy environment for the family who lives there:
- An energy recovery ventilator that brings in filtered fresh air
- A passive radon venting system
- 12-mil-thick polyethylene floor vapor barrier to keep soil gasses out
- low-VOC paints and finishes
“Before we moved, we were living in an 800-square-foot residence and often paying over $200-$225 for utilities. Here, we have more space (over 1,300 square feet) but our utility bill is less than $100. To me, this speaks volumes about the quality of construction that went into this house. We are so happy to be here!”Home Resident