A look at why energy-efficient windows
are now better than ever

If you install replacement windows for a living, you don’t need us to remind you that your competition is intense. Energy- efficiency mania is, obviously, the main reason that window retrofits are such big business these days (about $3-billion annually in product alone, not including labour, in Canada).

There is an endless supply of windows out there that need replacing. Some estimates say there are almost a billion single-pane windows still in service in the U.S. Who knows what the number is in Canada (using the old “divide by 10” rule we’d be looking at about 100-million units), but whenever you see a house with old- style windows, you are looking at a home that is spilling 30 per cent of its increasingly expensive energy into the great outdoors.

Up-to-date, energyefficient windows, such as those with the Energy Star label, will result in a home’s energy usage dropping by an average of 10 to 12 percent, experts say.

The challenge for the consumer (and the opportunity for a smart contractor, who can cut through the confusion) is that there are so many manufacturers and windows to choose from. For example, there are almost 450 Energy Star – certified window manufacturers listed with Natural Resources Canada (NRCan) alone, and that doesn’t even include the lower-end suppliers. How can you, as a contractor, help educate your clients on the right windows for them?

Well, the Energy Star rating is a good place to start. Launched in the U.S. in the early 1990s, it is now well established in the public’s mind in Canada. This seal of energy-efficiency approval appears on everything from building materials (for example, insulation) to furnaces, home appliance, and computers.

In the windows business, Energy Star has also become a great marketing tool for manufacturers and contractors. “I think it’s the major reason that the consumer is much more aware than they were even five years ago about energyefficient products,” says George Warren, president of London, Ont. based Centennial Windows & Doors, the first window manufacturer in Canada to receive Energy Star certification, some 10 years ago. “Energy Star is a tremendous vehicle,” Warren says. “The NRC’s website [nrcan.gc.ca] is sort of like ‘Energy 101’ for the public when it comes to windows.”

A Tougher Test of Quality

As successful as Energy Star has been at educating the public about superior windows, in some ways it was beginning to become a victim of its own success. So many manufacturers had raised the quality of their products to qualify for this influential rating, that NRCan recently decided to toughen up its standards.

As of last October, NRCan moved each one of the four climate zones (Zones A, B, C, and D) in Canada further south. In other words, what used to be an Energy Star–qualifying window in Northern B.C. is now (approximately) the correct window for the Lower Mainland. So a consumer buying an Energy Star window in 2011 is buying a product that has met a higher standard than ever before.

These changes to the specs have been well received by the window manufacturers in Canada. “As it applies to Canada, they have raised the bar,” says Brad West, vicepresident of Jeld-Wen Canada, one the country’s largest window and door manufacturers. “It got to the point where almost everyone had an Energy Star window, and if every [manufacturer] is Energy Star compliant, then there is less of an advantage to an Energy Star product. They have made it more rigorous and that is a good thing.”

Actually, the changes made last year are only the beginning of the tighteningup of the Energy Star standard. Even tougher specifications for windows, doors, skylights (and other building products) are expected to be put in place in 2013.

Understanding Energy Rating and U-Values

Windows produced in Canada (and in the United States, though the standards differ) come with stickers that give the purchaser valuable information on the energy effciency of the product. In Canada, the two common stickers are the Energy Star label and the CSA label. And the most important number on any ratings sticker is the Energy Rating (ER).

The ER measures a window’s overall energy performance, so the higher the ER, the better. The ER gives a complete picture of a window’s energy efficiency taking into account not only the window’s insulating capacity, but also its air-tightness and solar gain (the extent to which a window heats up in sunlight). Under the revised rating system, window ERs now range from 0 to 50 in Canada. Currently, the most energy-efficient windows in Canada have ERs in the low 40s, Warren says. These are generally triplepane windows. Doublepane windows max out in the low- to mid-30s.

There is also something called a U-Value, another measure of energy efficiency. As opposed to the ER, where you want a high number, the U-Value measures how quickly heat fl ows through a window, so the lower the U-Value, the better. To qualify as an Energy Star product, windows don’t have to make grade in both U-Value and Energy Rating, but they do have to meet or exceed the benchmark on one of them. (For more info on window ratings – and some installation tips – see our guest column, “Window Wise”.)

By the way, the industry doesn’t use R-values for windows. This is just one of those confusing aspects of window energy efficiency that is hard to explain to customers. Generally speaking, however, the most energy-efficient windows on the market in Canada, right now, would rate about an R-value of 10. Old-style, inefficient, leaky windows that don’t have modern inert-gas fillers, would rate about a one. Or close to a zero in the case of a single pane of glass.

Read the full article here: Top_Glass_Renovation_Contractor.pdf