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Toward Integration of Building Science

Posted by GBM Research

Aug 26, 2014 7:48:09 PM

OVER THE YEARS, the Department of Energy’s Building America (BA) program has filled a critical gap by funding research on innovations for high-performing homes, both new and existing. But the biggest obstacles to advancing building science are not technological, says Sam Rashkin, the DOE’s chief architect of the Building Technologies Office. The larger hurdle is market adoption, which has several facets, including an inadequate number of skilled professionals. After all, this critical research doesn’t do any good if only a select few people know how to access and implement it.

That’s where the Building America Solutions Center comes in. This website and database, which went live in January of last year, presents 20-plus years of research into a user-friendly format.

“It’s better, faster, cheaper,” says Rashkin, and represents a “complete flip” from the old library, which contained fixed, difficult-to-navigate content. Through the new interface, users can filter searches according to building components, download images, CAD files and case studies or jump straight to the Energy Star checklist. The Solutions Center already has a built-in set of users from the Energy Star and Zero Energy Ready Home programs, but anyone can access the site. Registering is free and allows users to access all the content—and even add to it.

For example, if someone has knowledge about a technique that’s specific to a particular climate zone, he or she can submit a comment clarifying, correcting or adding to the information already present. The comment is then peer reviewed, and if accepted, the original content is updated to reflect the new information.

“What’s really going to make this ‘grow up’ is the user feedback,” says Rashkin. That and the addition of new research results and case studies, which BA teams and the National Laboratories will continue funneling into the site.

Visit the Solutions Center at

Another Integrative Tool A new standardized data transfer protocol called HPXML allows home performance software programs to “talk” to each other.

Many software platforms are available for recording the results of home energy audits and analyzing home energy performance. But because states and utilities have adopted different tools for compiling and analyzing data, home performance companies that participate in multiple utility programs or regions need to be proficient in several. This means added training cost and IT infrastructure. Fortunately, the Standard for Home Performance-Related Data Transfer, informally known as HPXML, was published in June 2013. This tool, developed by the Building Performance Institute (BPI) and National Home Performance Council [with support from the National Renewable Energy Laboratory (NREL) and many other stakeholders], facilitates communication and the exchange of information among contractors, raters and other actors in the home performance industry by providing a standardized format for collecting and presenting data.

“The potential for reducing contractor costs is the most important end result,” says Robin LeBaron, senior advisor for policy and research for the Home Performance Coalition.

Using this software standard slashes paperwork and processing time, and could potentially reduce the overhead required to participate in high-performance home programs by 20 percent. LeBaron says HPXML also provides a platform for drawing more precise correlations between measures implanted and energy consumption. The standard has been pilot-tested in New York, Virginia and Arizona. Learn more at






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Advanced Framing Best Practices for a Tighter Thermal Envelope

Posted by GBM Research

Aug 26, 2014 7:36:20 PM

ADVANCED FRAMING TECHNIQUES that reduce the amount of framing in stud-framed walls improve their thermal performance. There’s more room for insulation, and thermal bridging—the heat transfer that happens through wood framing and extends from the inside surface to the outside surface of the wall—is reduced. Unfortunately, builders have been slow to adopt advanced framing methods because the techniques are nonstandard, and because implementation can require design and materials changes. A Building America team, the Partnership for Home Innovation (PHI), led by the Home Innovation Research Labs, have tested three advanced framing techniques that improve the thermal performance of the building enclosure, reduce the cost of energy-efficient construction and simplify the construction process.

Continuous Drywall at Interior Partitions
Drywall typically serves as the interior air barrier for the home’s thermal envelope or building shell. One weak spot is the corners of rooms where sheets of drywall come together; the air seal here relies on the integrity of the tape and mudding. Installing drywall continuously along the inside of the exterior walls of the home provides significant improvement in air tightness for stud-framed walls. All interior walls are framed so that a ¾-to 1-inch gap is left between the interior wall and the exterior wall. To stabilize the interior wall framing, walls are anchored to the top plate with flat plate connectors. Drywall is slipped through this gap as it is installed along the interior side of the exterior walls in one continuous path; then, interior walls are drywalled. The drywall sheets along the exterior walls are installed so that seams do not align with room corners.

Rim Joist Window Headers
In two-story homes, the space above the first-floor windows and doors is often composed of solid wood—such as two or three 2’ x 10’s or 2’ x 12’s—to equal the thickness of the wall. Traditionally, the solid header has been justified to adequately support the building load. Research shows that the rim joist for the second floor, which typically sits about one to two feet above the window frame, has adequate structural strength to support building load; therefore, no additional framing—other than the king studs on each side of the door or window—is needed to carry the load. The space above the door or window is left open and can be insulated like the rest of the wall. This technique saves time, labor and materials costs, while adding to the overall thermal performance of the wall.

Continuous Sheathing for Raised Heel Trusses
For builders used to building with standard trusses, using raised heel trusses could seem complicated, time consuming and expensive. Concerns about adequate support led builders to install blocking at each rafter bay to hold the trusses in place—a difficult, labor-intensive job. Home Innovation Research Labs found that a simpler solution provides adequate support: installing oversized OSB wall sheathing that extends up along the back of the raised heel, providing bracing for the trusses. The sheathing layer doubles as a wind baffle, allowing the insulation to fill the space above the outer walls to full height without spilling over into the soffit vents. Air flow is still provided through the space between the roof rafters above the top of the sheathing. This solution saves time and money by eliminating the separate steps of installing blocking and baffles, and provides some wind uplift resistance. The only additional cost is the purchase of taller OSB panels, but 9- and 10-foot lengths are readily available.

Winchester/Camberley Homes New Construction Test House The NAHB Research Center partnered with production builder Winchester Homes, Inc. to build a new construction test house, with the goal of improving energy efficiency by 30 percent over the Building America B10 benchmark. The strategies included optimized framing, air sealing, insulation and space conditioning system designs that are cost-effective on a production basis. The three-story Victorian-style house was built as a model home in Silver Spring, Maryland in 2011. A blower door test conducted after finishing yielded an infiltration rate of 1.9 ACH at 50 Pa. Factory-built wall panels consist of 2’ × 6’ wood frame, 24” on center, with ½-inch OSB sheathing. Structural rim headers replaced first-floor headers and jack studs; unnecessary blocking, studs and cripples were also eliminated. Second-floor headers were engineered to minimize dimensions to reduce initial cost, reduce thermal bridging and increase wall insulation. Second top plates and a housewrap were installed in the field. Cladding was fiber-cement siding. The continuous drywall method reduced framing air losses. Raised heel trusses with two-foot overhangs accommodated the full depth of insulation and insulation baffles at the eaves, notably at the sloped ceilings of the third floor.

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This Odor-Free Urinal Works Without Water

Posted by GBM Research

Jun 24, 2014 7:41:00 AM

By Klaus Reichardt

ADMITTEDLY, URINALS ARE NOT an everyday topic of conversation. And when it comes to homes and apartments, they almost never enter the discussion. However, that may be changing and changing very soon.

Home urinals, ranging in popularity, have been found in parts of Asia, Europe, Australia, and even in India. However, the trend in the United States is still in its infancy. In addition, the economy, which has severely impacted the housing construction industry, has slowed things down considerably.

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Housewrap: What's the Difference?

Posted by GBM Research

Jun 9, 2014 8:46:00 PM

IT'S A CONUNDRUM: How do you prevent water from entering a building, while also allowing any moisture that does make its way in to escape? This is the formidable task given to housewraps, and increasingly to roof underlayments. Housewrap, a common type of weather-resistive barrier (WRB), is installed between the cladding layer and the sheathing, while roofing underlayments go directly under shingles or other roofing material, forming a second line of defense against the elements.

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Off-the-Shelf HVAC

Posted by GBM Research

May 28, 2014 3:53:00 PM

What are the best available HVAC solutions for low-load, high-performance homes and apartments? What is currently available in the market? What are the limitations of these systems?

HIGH-PERFORMANCE HOMES REQUIRE SMALLER heating and cooling systems, yet common systems installed in existing homes are often not designed to be small enough for low-load structures. Air distribution, humidity control and comfort require different strategies than in less-efficient homes.

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