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February 14, 2004
By J.C. MYERS Correspondent
Nearly 1,000 building professionals, from architects and contractors to engineers and efficiency experts, gathered in Burlington last week to get up to speed on the latest building and energy conservation techniques.
The event was the "Better Buildings by Design 2004" conference, which offered 32 workshops by 27 presenters who held sessions that ran the gamut from a presentation of an advanced "High Performance Design Guide," a design tool for architects working on plans for commercial buildings, to basic workshops on how to deal with mold on your bathroom ceiling and how to seal up leaks in your attic.
The conference, held last Wednesday and Thursday at the Sheraton Burlington, was organized by Efficiency Vermont, the nation's first statewide provider of energy efficiency services. Created by the Legislature in 1999, Efficiency Vermont helps homeowners reduce their energy use. It's funded by an energy efficiency charge on Vermonters' electric bills.
Human thinking about how to improve shelter is nothing new, as some sessions at the conference revealed.
Susan Maxman, an architect who gave the keynote speech at the conference, showed a slide of a native American cave dwelling in the Southwest. The building complex took advantage of the angle of the sun: The cliffs above blocked out the high, hot summer sun, and took advantage of the warming effects of the lower angle of the winter sun.
According to Maxman, "green" thinking deserves a priority over what usually comes first: the bottom line. It is the responsibility of designers to "reduce the human footprint on our ecosystem," she said.
"Green" buildings are thoughtfully sited in the natural environment and are constructed from local materials. She said the "green" approach also minimizes impacts on the site, such as tree removal and re-grading, relies on natural light and heat from the sun and utilizes recycled gray water.
Maxman related the challenge her firm faced when it designed a student dormitory for Penn State University. The dorm was to be located in a grove of trees the school did not want to remove. So her firm designed the building as a series of blocks that were woven through the trees - one section adjoined to another with short hallways or "knuckles."
She said an animal shelter her firm designed in Pennsylvania uses "light scoops" to provide natural light for the animals, thus eliminating the need for electric lighting in that area of the building.
Here in Vermont, Middlebury College received an Efficiency Vermont award at the conference for the school's effort to make its building projects "sustainable."
Middlebury evaluates the sustainability of its building projects, and routinely works with Efficiency Vermont to design buildings that reduce pollution, minimize waste and use local and recycled materials.
Dave Epstein, a partner with Truex Cullins & Partners, a Burlington architectural firm, said the "Better Buildings" conference helps him to get his clients to "build responsibly." He said that efficiency design considerations require a commitment from the beginning and estimated that they add a little time to the building process, yet add only about 2 percent in up front costs. "In the long run" he argues, however "it saves costs, and it's just the right thing to do."
Mike Mitton, a builder from Maine, said the conference gives him technical information he needs and enables him to talk to his clients about new techniques and materials for improved air-sealing and indoor air quality.
Mitton says that in Vermont many builders really "get it" when it comes to efficiency issues, but that's less true in Maine.
So what does it mean to "get it"? Bret Hamilton, a presenter for the workshop, "Tight done right," explains that for many older homes, "the wood studs are actually performing better than the insulation between them." He adds that "We understand insulation well, but not air movement." Heated air in a building rises and escapes out the top, drawing cold air in at the bottom, like a huge chimney because of air pressure differentials created in winter by the denser cold air outside and the less dense warm air inside a house and because of a phenomenon known as the "stack effect."
Conference attendees were asked to "visualize a continuous air barrier" around the living space of the house. A good air barrier was described as one that's continuous, durable, rigid, shapeable, seal-able and assembled on site. Attendees were told plastic sheeting, fiberglass insulation, tape and anything that comes in a roll - the construction industry's standard for air sealing in the past - are all ineffective. Examples of good air barrier materials are drywall, plywood, rigid insulation, sheet metal, cellulose insulation and spray foam insulation.
A key issue at the conference was moisture control, which can create mold and affect the longevity of the building and the effectiveness of the insulation. Like the air barrier, the moisture barrier should have continuous integrity, that is, no holes.
David Keefe of Efficiency Vermont said the construction trade has relied on the "Goldilocks Theory" - the notion that for proper indoor air quality you don't want an insulated building to be "too tight" or "too loose," but "just right." In fact, he said, buildings should be as tight as possible, and then ventilated. Some modern ventilation systems, called "heat exchanging air exchangers" actually warm the cold air coming in with the warm air going out. Most are just an efficient, quiet fan attached to a sealed duct leading to the outside.
Indoor air quality was also a hot topic. In "tight" houses, wood stoves have been known to burn backward, drawing air down the chimney and spewing deadly carbon monoxide into the living space. Each person needs 15 cubic feet per minute of air, or 3.5 air changes in the living space per hour. Ventilation also controls moisture.
Other efficiency concerns discussed at the conference included sizing heating and cooling systems appropriately and using "energy-star" rated appliances and lighting.
There are ways to retrofit older houses, according to John Unger Murphy of Murphy's Cell Tech, a St. Johnsbury company which installs insulation. He said the most important considerations are an energy audit (using infrared scanning to see where heat escapes), assuring window and door gaskets are functioning and dealing with heat loss and moisture problems that compromise the structural integrity of the house, such as ice dams on the roof, or mold and rot issues.
Bill Powell, director of member services for the Washington Electric Co-op in East Montpelier, said it pays to think of energy efficiency as a basic way to save money.
"Our big home expenses are mortgage, taxes, and heating and energy costs," Powell said. "You can't easily control taxes or payments; you can control energy costs."
Powell said most people are content to pay the same energy costs year to year, but if they put some of that money up front "that's savings you could spend going out to the movies and eating pizza."
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