Window shopping

Leaky windows can be the single largest source of energy waste in your home, and when it comes to shopping for new windows there are three things you need to look at before you buy: the quality of the windows themselves; the installation techniques applied to the job; and the support offered by your dealer afterwards. And within each of these categories are many hard-to-assess issues. That's why industry and government players have come together recently to put guardrails around the process, applying standards and certification to an otherwise unregulated industry. Knowing about these useful tools is the first step towards any successful window replacement job.

In January 2001, the Canadian Standards Association (CSA) began administering the performance certification program of the Canadian Window and Door Manufacturers Association. That's good news because it means you don't have to guess how well particular windows do their job. The hard work of conducting lab tests to measure things like wind and rain resistance and thermal performance have already been done by a third party with no vested interest in the results. And windows that have proven a minimum level of trustworthiness now carry the familiar CSA logo. You can get a list of CSA Certified Products online (search for product class number 8029-02), or call 1-800-463-6727.

Of the 2000 window manufacturers in Canada, less than 30 currently have CSA-certified products. And even these companies offer differing levels of window performance depending on designs and features. You should also know that not all certified companies sell windows that are certified. CSA approval is an excellent technical starting point for window selection, but it doesn't end there. Performance is also affected by window style and glazing options.

As you shop, you'll find three technical terms you need to understand: low-e glass coatings; argon gas; and warm-edge design. Low-e is short for low emissivity, a reference to a transparent coating that improves window performance by reflecting heat back into your home during winter. It also works in reverse, reflecting summertime heat back out during the warm months, keeping your place cooler when it needs to be. There's another advantage to low-e, too. The best versions of the coating filter out 80% of the sun's UV rays, reducing fabric fade and plastic deterioration indoors.

Argon gas is a chemical element, and it also functions as an invisible window insulation option. Since it has better thermal properties than air, argon gas is a valuable enhancement when injected between the panes of sealed window glazings. Other insulating gases are becoming available, but argon is the most popular and least expensive.

To understand the value of warm-edge window glazings, you need to know something about typical double-pane glazing design. Various systems include two, sometimes three pieces of glass separated by spacers (usually about 1/2-inch thick), joined into a unit with a flexible sealant. Traditionally, this spacer has been made of aluminum, but better energy performance is possible with spacers made out of less thermally conductive materials, like vinyl. These "warm-edge glazings" boost window performance by reducing heat loss around the edges via conduction. Warm edge windows are also less prone to condensation.

The performance of every new window ultimately depends on installation quality. An excellent window, installed poorly, simply doesn't work up to potential. That's why the Window Wise certification program was developed. It's an independent, Canadian-based program that offers specific training to window installers. It also audits their field performance after the fact with random third-party inspections, and warrants installation quality for the homeowner, up to five years after the work has been done. Window Wise doesn't eliminate the need to apply due diligence when selecting an installation firm, but it does greatly improve your chances of getting good work.

And good work is really what it's all about. Wise window decisions come from doing your homework, learning about technical options, then enjoying the comfort and security of a well managed home. It's more trouble at first, but the results are worth it.