Home Improvement : High-Tech Insulation Improves Windows

There’s good news from Wisconsin and California for homeowners, builders and architects who have despaired of having windows and an energy-efficient house at the same time.

Windows are responsible for up to 40% of the energy needed to heat and cool a typical home, through heat loss and gain through the glass, according to a spokesman for Southwall Technologies Inc., Palo Alto, manufacturers and marketers of Heat Mirror. This “technological breakthrough in window insulation” is capable of reducing heat loss and heat gain through double-pane windows by up to 60% and it has the added benefit of being colorless.

Hurd Millwork Co., Medford, Wis., has taken this concept to produce its Sunbelter line of wood windows and patio doors, reportedly the first and only line of transparent sun-shading wood windows and patio doors on the market.

“The Sunbelter with Heat Mirror 66 gives homeowners, builders and architects, weary of darkened windows, the opportunity to control solar heat and cut air conditioning costs while enjoying the look of a clear window,” according to Roy Doering, sales and marketing manager at Hurd. Wood-framed windows and patio doors are regaining some of the popularity they had before the arrival of aluminum-framed units, especially in premium quality homes.

The Sunbelter, available for new and retrofit construction in either primed Ponderosa pine or pine with extruded aluminum cladding, admits 53% less heat than single-pane windows, 45% less heat than double-pane ones and 33% less heat than “high performance” tinted glass, he added.

“Hurd Sunbelter not only provides superior shading performance, but also has the highest insulation rating (R4.2) of any wood window, an improvement of 133% over conventional double-pane glass,” Doering said.

In the Southland, the Hurd Sunbelter is available from California Wood Window, 11338 Moorpark St., Suite 203, North Hollywood, and 948 N. Elm St., Orange, and San Diego Wood Window, 10855 Sorrento Valley Road, San Diego.

First announced in the April 1977 issue of Scientific American, the Heat Mirror technology was developed in the early 1970s by a team of architects, scientists and engineers from the Massachusetts Institute of Technology.