Affordable Efficiency

Habitat for Humanity International’s goal is to “build simple, decent, affordable houses in partnership with those in need of adequate shelter.” Habitat is reportedly the world’s largest homebuilder. Since 1976, they have built almost 100,000 homes worldwide, including some 30,000 in the United States. Most homes built by Habitat’s U.S. affiliates are three- and four-bedroom models ranging between 1,000 and 1,200 square feet.

During the mid-1990s, Habitat’s central office, based in Americus, Georgia, began examining the organization’s energy efficiency and “green building” practices. They gathered advice from building scientists at the Florida Solar Energy Center, the Energy and Environmental Building Association (Minneapolis), the Southface Institute (Atlanta), and Building Science Corporation (Massachusetts). Thereafter, Habitat began recommending a new performance benchmark for its homes: EPA’s Energy Star threshold—30% more efficient than a home built to CABO’s 1995 Model Energy Code.

Habitat’s central office doesn’t prescribe minimum efficiency standards for homes built by affiliates. “We strongly promote energy efficiency,” said Nevil Eastwood, in charge of construction and environmental resources for Habitat International. “We are aware of construction costs we add that increase the first cost of buying the home. However, we take the long-term view of ‘affordability,’ which means a home must be affordable to live in, not just buy. In fact, building to the 5-Star level has actually increased the number of people who can qualify for one of our homes; since their monthly energy bills will be lower, their income doesn’t have to be as high. So we encourage all our affiliates to meet the Energy Star level, but ultimately we leave that decision up to those affiliates.”

Habitat set up a “Green Team” to train personnel from affiliates interested in upgrading their energy efficiency and resource efficiency (use of materials). Several key energy features they strongly recommend include solar-friendly building orientation, low-e windows, air sealing, ductwork sealed with mastic, and good ventilation. The latter consists of vented kitchen fans, quiet and durable bath fans, and fresh air brought in through a duct from the outdoors whenever the air handler fan operates for heating or cooling purposes. Habitat frequently tests home tightness with a blower door.

One of the first homes to incorporate these standards was the Denver Habitat affiliate’s 1997 “Earth Smart home.” The National Renewable Energy Laboratory provided both pre-construction modeling of the savings projected by the upgraded energy measures, plus on-site monitoring of energy performance and consumption. Bottom line savings: the Earth Smart home required 60% less heating energy than the comparison home built to the CABO Model Energy Code. Actual total utility bills (electric and gas) range from about $25 per month (summer) to about $50 per month (winter); that represents a huge savings compared to the same family’s utility bills in their previous inefficient apartment ($70 summer to $175 winter).

Last Updated: 08/21/2003