‘Active House’ Makes U.S. Debut
A St. Louis project extends the reach of this new green-building initiative
Does the U.S. need another green-building standard?
St. Louis builder Matt Belcher and the Active House Alliance, a consortium of European firms ledLight-emitting diode. Illumination technology that produces light by running electrical current through a semiconductor diode. LED lamps are much longer lasting and much more energy efficient than incandescent lamps; unlike fluorescent lamps, LED lamps do not contain mercury and can be readily dimmed. by Velux, are hoping so, and a nearly complete 2,500-sq. ft. house in a St. Louis suburb will be its U.S. debut.
Active House is a two-year-old program launched in Brussels that promotes the construction of houses that are energy-efficient, comfortable to live in, and positive for the environment.
Those goals seem in line with green-building programs already established here, including LEED for HomesLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. , the National Green Building Standard and even PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates.. Yet the consortium apparently sees enough differences in these competing approaches to press ahead.
Active House certification requires third-party verification, and relatively few of them have been built. Green Building Advisor contributor Richard Defendorf profiled one Active House built in Russia in a 2011 blog. The Alliance also lists a number of ”Active House cases” at its web site.
Construction of the house in Webster Groves, not too far from the center of St. Louis, is the start of efforts by the European consortium to extend its reach here.
What the Active House standard looks like
The 1st edition of the Active House specification (subtitled “buildings that give more than they take”) is a 44-page document that can be downloaded from the alliance’s web site in either English or German.
It lays out a number of “key principles” in three areas:
- Energy. Buildings should be energy efficient, “easy to operate,” exploit a number of energy sources and “substantially” exceed minimum energy standards.
- Indoor climate. In addition to high indoor air quality, the house interior should promote “health, comfort and sense of well-being.” It should also be easy for occupants to control.
- Environment. Houses should have minimal impact on the environment, “add to local biodiversity” and be constructed of materials with a high recycled content.
“Active House proposes a target framework for how to design and renovate buildings that contribute positively to human health and wellbeing by focusing on the indoor and outdoor environment and the use of renewable energy,” the document’s introductory section explains. “An Active House is evaluated on the basis of the interaction between energy consumption, indoor climate conditions and impact on the external environment.”
Like other green-building initiatives, this one lists measurable objectives in a number of areas. Annual energy use, for example, must be 30 kWh or less per square meter per year to hit the top of four rankings (that’s double the amount allowed under the Passivehaus standard). Houses that produce all of the energy they need on site get a no. 1 ranking in the energy supply section, or a no 2 ranking if they produce more than 50% of the energy they use. There also are goals for the amount of daylight the buildings take advantage of, maximum and minimum indoor temperatures, and maximum permissible carbon dioxide levels.
Active House comes to America
The new house at the corner of Gray and West Swon Avenues in Webster Groves is the work of Belcher’s firm, his frequent collaborator Kim Hibbs of Hibbs Homes, architect Jeff Day and several others. But it really started when Velux got in touch with Belcher and asked him whether he’d be interested in building the first Active House on this side of the Atlantic.
The company found him, Belcher says, through its network of Velux dealers here, and Belcher flew to Charleston to meet with alliance officials. With a number of green-building projects already under his belt, Belcher thought an Active House project would be a good fit, even if early Active Houses tended toward modern designs.
“I felt confident to build to these levels,” he says, “but also knowing what price point we’d be at I kind of knew we’d be in the inner suburbs of St. Louis and I also knew their architectural review boards were not going to let me build an ultra-modern looking house in these old neighborhoods. [Active House] was fine with that, and in fact they came to really like the idea that we had to design for an infill house and make it an Active House.”
Belcher and Hibbs approached Day, with whom they’d worked in the past, and began looking for a likely client. That turned out to be David Smith, a local accountant, who’d hired Day to design a remodel for him in the past. Smith had contacted Day to tell him he was thinking of building a new house.
“And Jeff says, ‘Have I got the perfect project for you,’” Belcher says. “David’s a CPA and 10 minutes into the conversation he got the economics of it. It was a slam-dunk.”
What Smith and his young family got was a two-story bungalow-style house made with structural insulated panels (R-25 walls and R-45 roof) for about $500,000, or $200 a square foot. It’s heated with a 98% efficient gas furnace, cooled with a SEER(SEER) The efficiency of central air conditioners is rated by the Seasonal Energy Efficiency Ratio. The higher the SEER rating of a unit, the more energy efficient it is. The SEER rating is Btu of cooling output during a typical hot season divided by the total electric energy in watt-hours to run the unit. For residential air conditioners, the federal minimum is 13 SEER. For an Energy Star unit, 14 SEER. Manufacturers sell 18-20 SEER units, but they are expensive. 20 air conditioning unit and serviced by an energy-recovery ventilator, Belcher says. It has 4.88 kW worth of photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. panels on the roof, and solar collectors for domestic hot water.
“People ask about the cost of the equipment to make it perform and that probably added about 7% total to the cost of the house,” Belcher says. “But the upgrades in tile, high-end hardwood and all that stuff probably added 10%. So it’s kind of relative to the construction costs of the house. People get the wrong idea of what those [performance] upgrades are.”
Active House liked the fact the house would be an infill project, and also because of the St. Louis climate.
“One of the things that became appealing to the Active House Alliance was that we heat half the year and cool half the year,” Belcher says. “We’re in a mixed humid climate zone, so we have to build for both extremes, plus we’re in tornado alley, and in the New Madrid seismic zone. We’re building bunkers that look like houses.”
The house, described in an article in the St. Louis Post-Dispatch, will get a blower-door testTest used to determine a home’s airtightness: a powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s airtightness can be determined. Operating the blower door also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas. later in March, as well as equipment allowing performance monitoring, before the Smiths move in. The project also has its own web site, which includes a project description, background on the Active House initiative, and more photographs of the project.
The house replaces an 80-year-old bungalow on the lot that was in poor repair. Belcher says they deconstructed the house, diverting 50 tons of materials from landfills and supplying a local Habitat ReStore outlet with windows and other materials.
What makes Active House different?
Matt Belcher's selection to spearhead the Active House movement in the U.S. might seem a little ironic. Among his many professional connections is a seat on the board of directors of the National Association of Home Builders, which helped to develop the National Green Building Standard (also known by its more formal moniker, ASNI-ICC 700). Belcher, in fact, is chairman of NAHB’s green-building subcommittee.
But Belcher's close association with the ICC-700 has done nothing to dim his enthusiasm for this one. The Webster Groves project is designed to qualify for a number of sustainable-building designations, including Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners., Building America Builders ChallengeA U.S. Department of Energy (DOE) program to promote the construction of “better than Energy Star” homes. A home must have a maximum HERS rating of 70 to meet Builders Challenge requirements., and the National Green Building Standard.
Belcher says the Active House standard could work in tandem with other green-building initiatives like NGBS, not necessarily replace them. "I view them as complementary, and expanding my marketing message," he says. He adds that Active House is "quite similar" to ICC-700 in that it takes a "holistic" approach to building design.
But the Active House specification, he says, puts more emphasis on daylightingUse of sunlight for daytime lighting needs. Daylighting strategies include solar orientation of windows as well as the use of skylights, clerestory windows, solar tubes, reflective surfaces, and interior glazing to allow light to move through a structure. and other design features that make a house healthy and comfortable.
“I tell you what I like about Active House,” Belcher says, “and, again, I’m chair of NBH’s green building subcommittee, and a big believer in the National Green Building Standard because it’s a great specification. What I like about Active House is the fact that one of their main goals was occupant comfort.
“I’m concerned some of the programs out there are more about the building than the occupant," he says. "Obviously, we need to have high performance buildings but we can’t forget who’s going to live in those houses, either.”
Belcher also is getting a kick out of helping to develop the specification.
"Besides being involved in assisting with the development of their specification, which is cool, interacting with building codes and science geeks like me from many other countries is very cool," he says. Whether the process translates into a program that North American builders and buying public embrace, however, remains to be seen.
"The jury's still out, frankly," Belcher says.
- Active House USA
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