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High-Tech Window Glazing

Posted by Suchi Rudra

Jul 1, 2014 2:00:00 PM

Windows by the Numbers (and Letters)

There are several ways to measure a window’s performance. Your region’s climate will dictate which factors to favor.

U-factor: This value measures how well the window prevents heat from escaping a building, and takes into account the window’s framing, glazing, weather-stripping and more. The lower the number, the better the performance. Windows with low U-factors work well in cold climates.

Solar Heat Gain Coefficient (SHGC): This factor measures how well the window blocks radiant heat, on a scale from 0 to 1. The lower the number, the more heat is blocked. Windows with low SHGC value are suitable for hot climates.

Visible Transmittance (VT): This number measures how much sunlight the window allows into the building, on a scale from 0 to 1. A higher VT value means better daylighting.

R-value: This factor measures the window’s resistance to heat loss, or conductance. In general, R-value isn’t the best measure of a window’s total performance.

Low-e Glass: Low emissivity coatings reflect UV and infrared rays, but allow visible sunlight to pass through the glass. These coatings help keep heat out of a building in summer and keep it from escaping in winter.
WHEN IT COMES TO energy efficiency, windows are problematic; they’re essentially holes in an otherwise insulated wall. Glass makes up about 15 percent of the wall space in an average home, and inefficient windows can cost over $700 a year in wasted heating and cooling costs. This loss accounts for approximately 2 percent of all energy consumption in the U.S. Upgrading window products, whether you retrofit or replace, means upgrading building performance and cutting back on hundreds of dollars in energy bills.

Taking the climate zone into consideration is one of the most important factors in selecting the right kind of window product for a new or existing residential construction. Typically, the colder the climate, the lower the U-factor of the window should be. But regardless of region, you also need to control the discrepancy between indoor and outdoor temperatures, the quantity and quality of sunlight and, of course, air leakage.

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Topics: High-Performance Windows, Windows, energy efficient windows, Low-E Window glazing, Building Science

Four-Part Harmony

Posted by Juliet Grable

Oct 2, 2013 12:49:00 PM

THE GUEST HOUSE at Buoy Bay was the prototype that launched the Cottage Series, one of eight pre-design series offered by Method Homes. It’s located at the south end of Orcas Island, one of the San Juan archipelago o­ff the Washington State coast. Architect Christopher Rost hopes his collaboration with Method Homes will open up opportunities in residential prefab.

“There are two factors limiting [the market] today,” he says. “The stigma of the mobile home and the emphasis on modern in high-end prefab.”

Rost has been practicing for over twenty years. He is Studio 29, along with his wife, Carol Rost, who serves as office and project manager and consultant. The couple moved to Orcas Island in 2006. Working in the beautiful but fragile environment prompted Rost to seek construction methods that minimized environmental impact; he also wanted to design structures that were flexible, expandable, and moveable. After briefly considering shipping containers, he concluded pre-fab was the way to go, especially for island construction, which is often characterized by hard-to access sites on steep slopes. In a bit of serendipity, Rost was approached by a client who was interested in both traditional cottage design and modular construction. He chose Washington-based Method Homes as a partner for the company’s experience in high-end prefab.
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Topics: Bamboo, 1500 square feet or less, solar, Windows, Energy Star, radiant heating systems, composite siding, prefabricated homes, Washington

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