A maze of glazing

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their home or project by offering-and understanding-the variety of available window glazing options.

"Different climates and styles of homes require different glazing options to maximize their efficiency," says Bob Eckert, residential market manager for Weather Shield Windows & Doors. "Windows can also help reduce noisy outdoor traffic sounds from entering a home."

Weather Shield, for example, offers eight different glazing options. ranging from a single-glazed glass that replicates historic homes but has minimal insulating value up to Value R-10 with three panes of glass for maximum efficiency.

"Everyone-whether for a new construction project or window replacement-should understand the key window technology before selecting a window," advises Eckert.

U-values represent the amount of heat that escapes through a wall, window, roof or other surface in an hour's time. The lower its U-value, the more energy efficient a material is.

BETTER AND BEST: Double-glazed (top right) and triple-glazed windows (below) provide greater energy efliciency and long{erm savings.

R-values are the direct opposite of U-values. R-values measure an object's resistance to heat flow. The higher a material's R-value, the lower its U-value and the less energy it will lose. A window's R-Value depends on three factors: the number of layers of glass (called glazing), what's between those layers (either air or gas), and whether one or more layers of glazing have been treated with a Low E coating.

Low E stands for low emissivity. a property un ique to materials that light can pass through. Filtering out part of the light spectrum (the part that transmits heat) greatly reduces a window's U-value and increases its R-value. In general, Low E windows are more energy efficient, moderate home temperatures, and reduce fading of fabrics.

Windows with single-glazing have a single pane of glass. These windows have a very low R-value and can be used best in structures such as garages and tool sheds, where energy efficiency is not a consideration.

A step up from single-glazed windows is a double-glazed window, also called Insulated or Insul glass windows. Either air or safe. colorless. odorless gas is tightly sealed between the two panes of glass. For added energy efficiency, one or both panes can be treated with a Low E coating to bring the window up to a Value R-5.

For the best energy efficient insulating power in a window, buyers should consider triple-glazed windows. Argon or a mixture of argon and krypton fill the spaces between the three panes of glass. Triple-glazed windows with Low E coatings on two of the panes dramatically improves energy efficiency and gives the homeowner a Value R-10 window.

"While it may be more expensive in the short-run to purchase a high R-

"A homeowner will save dollars on heating and cooling costs every month of the year for the life of the window."

Value window, the homeowner will save heating and cooling costs in the long run," says Eckert. "Three panes of glass with two Low E-coated surfaces provide year-round comfort and savings as well as filter the ultraviolet light that causes fading. This type of glazing option reduces heat coming into the home in the summer and helps retain daytime sunlight by reflecting warm air back into a room."

VEARS AFTER their developI. ment. flexible resin materials continue usurping wood for use as trim for arched windows and curved walls. New materials provide even greater advantages and closer similarities to the wood materials they replace.

Ultra-Flex Moulding Inc., San Marcos, Ca., recently developed a syntactic polymer formulation said to better duplicate the qualities of wood and provide even greater flexibility, without splitting, cracking or breaking.

Similarly, Allen Jones, president of Flex Trim Mouldings, Inc., Rancho Cucamonga, Ca., sees increased dura-