Lawn & Garden

(NAPS)-Whether remodeling or building a new home, knowing the right questions to ask before buying windows can save you time, trouble and money.

· Is the manufacturer certified? A sure sign of a well-constructed, quality unit is the certification label etched in the glass or printed on the spacers between the lites of glass.

Windows can earn one of three designations-C, CB or CBA-depending on test results. The CBA level is the highest rating and means a window has passed through three levels of simulated weatherization without showing signs of condensation or fogging.

· Does the window manufacturer offer a warranty? If you are considering purchasing a dual-pane, sealed window unit, ask about the manufacturer's warranty. A well-constructed unit should last a minimum of 10 years. If the window system fails in five years, causing excessive drafts or allowing condensation to form between the panes, will the manufacturer replace it?

Also inquire as to whether any of the window components are covered. For instance, Tremco, the manufacturer of the insulating glass edge spacer, Swiggle® Seal, offers window manufacturers a warranty on their product.

· What is the U-value of the window? Window manufacturers use U-values, a measure of heat transfer, to indicate thermal performance or energy efficiency. The lower the U-value, the better. A U-value of .40 is considered excellent.

· Is the window constructed with conventional or warm-edge spacers? Dual- and triple-pane windows are constructed with edge spacers designed to reduce heat loss around the window's edges. The materials used to construct these edge spacers can mean the difference between a drafty window edge and one that is well-insulated against the cold.

Some window manufacturers use aluminum spacers filled with moisture-absorbing material that helps prevent condensation from building up between the panes. However, because metal conducts heat, aluminum spacers diminish the insulation value of a window, resulting in a higher U-value.

Others have abandoned aluminum spacers for warm-edge spacers. But not all warm-edge seals perform identically. A window constructed with a warm-edge spacer such as Swiggle Seal will be nine degrees warmer and reduce condensation by up to 80 percent more than an identical window constructed with an aluminum spacer.

· Does the window have low-E glass? Regular, uncoated glass releases heat in winter and retains it in summer. To prevent this, some window manufacturers use low-Emissivity (low-E) coatings on one pane. Low-E coatings block the radiation that can account for as much as 60 percent of a window's heat loss. They also protect indoor furnishings from sun damage.

It makes sense to ask your contractor for recommendations, but a little homework of your own can help you end up with the most appropriate windows for your construction or remodeling project.

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