Serenbe: A Solar-Powered Development Trying to Solve Car Dependence

With EarthCraft certification being a requirement, energy performance of homes in Serenbe is relatively good; transit options being planned will also help save energy.

The net-zero-energy Bosch Demonstration Home at Serenbe.Photo Credit: Alex Wilson

After bringing some of the unique features of Serenbe, a New Urbanist community outside Atlanta, to you last week, today I’ll describe some of the energy features at the 1,000-acre development.

EarthCraft-certified

Serenbe is an EarthCraft Community, meaning that 100% of homes and commercial buildings must be built to EarthCraft standards. EarthCraft is one of the nation’s most successful regional green building programs. Developed by Southface in Atlanta, EarthCraft now boasts over 40,000 certified homes and a new commercial-building certification program.

EarthCraft energy standards aren’t close to those of the Passive House certification, but they are reasonably good and have done a great deal to improve the energy performance of homebuilding in the Southeast. The program requires blower door testing and has served to introduce this and other elements of high-performance building to the mainstream building industry.

One sees quite a few PV modules when walking around Serenbe.Photo Credit: Alex Wilson

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While EarthCraft compliance is the baseline for Serenbe, many homes go beyond that. Just completed a few weeks before my visit is the Proud Green Home, a project with numerous partners, including Southface, that is certified to Earthcraft Platinum standards, which are much more stringent than simply Earthcraft certified.

Net-zero-energy homes

Some homes at Serenbe are going well beyond even Earthcraft Platinum requirements. There are several net-zero-energy homes already built among the 140 completed homes and townhouses. “Net-zero-energy” means that solar-electric modules on a house provide all of the energy that home requires. Most of these all-electric homes rely on ground-source or water-source heat pumps (referred to by many, including Serenbe, as “geothermal” heating systems).

I’m usually not a huge fan of ground-source heat pumps. I’d rather put the money that would be spent on coils of tubing into the building envelope to reduce heating and cooling loads, then satisfy the remaining demand with much less expensive mini-split air-source heat pumps.

Steve Nygren, the developer and visionary behind Serenbe, pointed out to me several areas where clusters of net-zero-energy homes will be built, along with some net-zero-energy commercial buildings.

Walking around the development, one sees quite a few houses with solar-electric modules on their roofs, so even if net-zero-energy performance isn’t being obtained, such homes are at least relying on renewable energy for some of their energy demand.

The Proud Green Home at Serenbe.Photo Credit: Alex Wilson

Leaving the car at home

Lots of features at Serenbe are designed to encourage alternatives to the automobile that would reduce the transportation energy intensity of buildings there. Through wide sidewalks, traffic-calming features that improve pedestrian safety, and extensive pathways in the community, Serenbe is designed to be a pedestrian-friendly community that works well for walking and bicycling. These measures will be more successful at reducing car use, however, once there are more services and commercial space available in the Serenbe town centers.

For self-employed residents, I’m told that Serenbe is also a great place to live—and it has attracted quite a few such individuals.

Chattahoochee Hills, the recently formed municipality that includes Serenbe, is also developing a regional network of trails that will make longer-distance bicycle transportation more realistic—to surrounding towns and communities.  

The reality, however, is that for many residents, Serenbe is a bedroom community for Atlanta. For residents who work in the city, commuting by car is still the only option. That could change, though. Chatahoochee Hills has maintained a right-of-way for future transit along the South Fulton Parkway, Nygren told me.

The Bosch Experience Center.Photo Credit: Alex Wilson

Serenbe is also about five miles from Palmetto, Georgia, where there is a plan to use an existing rail line for passenger rail service into Atlanta. If rail service were developed connecting Serenbe and other area towns with Atlanta, that could help to dramatically reduce energy use—and the carbon footprint—of residents in the community.

Nygren, the ultimate cheerleader for Serenbe (and a resident of the town), is optimistic about that happening.

Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. In 2012 he founded the Resilient Design Institute. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.