A few years back, Tech Spec wrote about a near zero-energy home built by a consortium of companies put together by BASF Corp., ostensibly to prove that it could be done at a reasonable cost. The result was the first LEED platinum home in New Jersey, located in the hardscrabble city of Paterson. It had a rating of 34 on the Home Energy Rating System (HERS) Index, in which 100 equals compliance with the 2006 Energy Code and 0 equals, well, zero energy consumption.
Since then, Florham Park, N.J.-based BASF has been out talking to home builders, among them the big publics. And the company, in partnership with a mid-sized regional builder in Arizona—Pepper Viner Homes—has unveiled another near zero-energy home in Tucson. It sports a 19 on the HERS Index, which will make it the first LEED platinum home in Arizona, according to BASF. This one was intended to demonstrate that high-performance homes can be built on a production scale.
Given its location, the Pepper Viner home, which can been seen in detail at www.betterhomebetterplanet.com, did not call for insulating concrete forms (ICFs) as did the home in Paterson. It was instead built entirely with structural insulated panels (SIPs) filled with BASF's Sytropor insulation and covered on the exterior with BASF's Senergy stucco system. The underside and outer roof deck were coated with BASF polyurethane insulation. BASF also developed a concrete mix with a 40 percent recycled fly-ash concentration for the foundation.
The whole point of the project, according to Jack Armstrong, leader of building and construction markets in North America for BASF, was to “go from being a showcase to really a business case.” To that end, he says, “We are really trying to bundle all of the building envelope best practices and expertise and make that digestible for the average builder.”
THE RACE TO ZERO: Workers unload and assemble structural insulated panels at Pepper Viner's near zero-energy home in Tucson, Ariz.PHOTO: BASF CORP.
That, says Richard Barna, director of green building and building science for Pepper Viner, is precisely what the home did, albeit with a fair amount of up-front planning. “You have to look at the whole building process,” he says. “You can't do it piecemeal. Every builder has been so set in building homes a certain way. This whole process was about changing that mind-set.”
Foremost among the early plans were writing new specifications and training, particularly in building with SIPs. Exacting building efficiency standards were written into the specs before they went out to bid. The training, Barna says, “is still a challenge. You train one company, then they have layoffs, and you have to train another group.”
Once it's done, however, the building envelope can be “dried-in” in as little as a day. And in the end, the construction cost came out comparable to standard stick-built construction, with a modest premium for the SIPs, which Barna thinks will disappear as more builders use them. In the meantime though, he believes the savings from waste on site can almost make the cost of SIPs a wash with traditional framing and insulation. Cycle time can be cut as well.
If Congress passes anything close to the Waxman energy bill that made it through the U.S. House of Representatives last year, all builders will soon be forced to build to much higher efficiency codes. SIPs, and ICFs, look to be a reasonable way to get up to those codes. “They have to be addressed, sooner or later,” says Barna.
Correction: The Nov. 8, 2009, Tech Spec column featured a photo of the Vierti keypad from Lutron that was incorrectly cropped. A full-sized version of that photo can be seen at http://bit.ly/7r5HTv.