Net-zero energy homes on the rise

Steve Bostic of Amerisips Homes talks about the net-zero homes he's building at St. Johns Woods Parkway on Johns Island. (Tyrone Walker/

Several subdivision developments in the Charleston suburbs are offering super-efficient “green” homes designed to generate the energy they consume.

It’s part of a growing national trend in home construction that has arrived in the Lowcountry.

Net-zero homes, as they sometimes are called, are a niche within the booming “green homes” sector.

“In 2011, green construction was about a 17 percent share of the overall (home building) market, and that’s up from less than 2 percent just a few years ago,” said Kevin Morrow, senior Green Homes Program manager at the National Association of Home Builders.

By 2016, he said, green construction is expected to account for up to 38 percent of home building.

Net-zero homes go beyond “green” by adding alternative energy systems to houses that are tightly insulated and built to environmentally friendly standards. Such homes have been available from custom builders, but are now going to be built locally in numbers.

Two rival builders, Maryland-based Nexus EnergyHomes and Charleston-based Amerisips Homes, already have begun construction at locations in Summerville and on Johns Island. Nexus also will be building in Ridgeville, and a deal is in the works for Mount Pleasant.

“That’s going to be a home run for our company,” said Gorden Timmons, the developer working with Nexus. “When I saw their product, I knew we needed them here.”

Both builders use insulated structural panels that create exceptional insulation and outfit homes with power-generating solar panels. Nexus also uses geothermal heating and cooling, while Amerisips uses an advanced heat pump and energy-recovery system.

And both tout additional features such as high-efficiency appliances, on-demand water heating and high-tech home-systems monitoring.

Between the two builders, more than 100 homes are planned in the area, closer to 200 if all goes well. Those involved say they are creating the homes of the future, with low to no power bills and exceptional indoor air quality.

“We’re not looking at it as a gimmick or a marketing ploy,” said Mike Murphy, construction division president at Nexus. “We truly want to build the best, most energy-efficient homes we can build.”

Nexus has built homes in Frederick, Md., and broke ground in September on a development in downtown Philadelphia. The company is building in the Charleston area on 12 lots at the River Birch subdivision in Summerville and 30 lots at Bridlewood Farms in Ridgeville.

Nexus’ development in Frederick landed the company the Builder of the Year honor at the 2012 Energy Value Housing Awards. The company builds homes to meet the National Association of Home Builders Research Center’s “emerald” level of green home certification, the highest association rating for residential buildings.

On Johns Island, Amerisips is putting up “energy-free-living” homes on 35 lots in St. John’s Woods with the potential to add 100 more. The “sips” in the company name is an industry acronym for “structural insulated panels,” a sandwich of polystyrene pressed and glued between material such as oriented strandboard.

The result is strong panels that can serve as structural framing, insulation and interior and exterior walls all in one panel.

Amerisips uses SIPs panels for the floor, walls and roof of its homes. There’s no framing, roof trusses or interior load-bearing walls. Proponents of such construction say the homes are more efficient and stronger than stick-built homes.

“We can build (to withstand) up to 200-mph winds,” said Amerisips chairman Steve Bostic. “What we’re doing is building an air-tight house.”

Such homes need air-handling systems that bring in fresh, filtered air, and Amerisips and Nexus both boast of systems with extensive filtration.

“When you build an airtight box and put in state-of-the-art systems, you get better air quality,” Bostic said.

Super-efficient homes don’t need as much power as conventional ones, and that makes it easier to power them with alternative systems.

Net-zero homes are designed to generate enough power so that over 12 months, there’s no energy cost. In some months, they may draw power from the electric grid, and in others, they may generate power for the grid.

“It’s kind of a new concept in building,” said St. John’s Woods developer Edwin Pearlstine, who teamed up with Amerisips. “We have to find out if the consumer is willing to invest more to get the energy savings.”

Murphy of Nexus prefers the term “net-zero-capable” because the homeowner could use more power than expected.

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Newer construction methods combined with a steep drop in the price of solar panels and state and federal tax credits have made them more affordable than ever.

The homes that Amerisips and Nexus are building are more expensive than many homes for sale in Charleston, Berkeley and Dorchester counties, but they are cost-competitive with homes in the subdivisions where they are being constructed. That’s the mid-$250,000 range for Bridlewood Farms, the mid-$350,000 range at River Birch, and more than $400,000 at St. John’s Woods.

One interesting wrinkle on the home prices is that buyers would be entitled to substantial state and federal tax credits tied to solar and geothermal systems.

“Based on our preliminary numbers, Bridlewood will have (tax credits) somewhere in the range of $20,000 and River Birch around $25,000,” Murphy said.

So a net-zero home buyer could be largely free of power bills and also see their state and federal tax bills plunge temporarily.

Data from the S.C. Department of Revenue shows that so far, South Carolina residents have been slow to embrace solar systems. In 2011, fewer than 300 taxpayers claimed the credit in 2010.

There are some differences in the ways Nexus and Amerisips are building homes. Nexus homes at River Birch are being built on insulated slabs, with SIP walls and conventional roof construction methods, which Murphy said allows for more design options.

Amerisips is using SIPs for the entire building envelope at St. John’s Woods, where it is building above crawl spaces. The initial result is a home “shell” with no interior walls. Buyers get to decide on the interior layout.

Amerisips builds to the U.S. Green Building Council’s Leadership in Energy and Environmental Design platinum standard, the highest rating, as well as the Environmental Protection Agency’s Indoor airPLUS standard, according to Bostic.

Nexus is also an EPA Indoor airPLUS partner.

Bostic said his company has long-term plans to produce its own SIPs, precut for different home plans.

He compares the concept to the way that Sears used to sell homes through its catalog in the 1920s. A buyer would get the home plans and all the lumber, precut, delivered to a home site.

Reach David Slade at 937-5552 or Twitter @DSladeNews.