Window shopping

The clear truth about buying and installing new windows

By Jay Somerset

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While every window offers a glimpse of the outside world, not all are created equal. Some perform better than others at keeping the outside out and the inside in. And this depends on installation, materials and an extensive list of choices: frames made from wood, vinyl, aluminum or fibreglass; single-, double- or triplepane; argon or krypton inert gas; and an assortment of glazes that makes Tim Hortons' seem modest. Then there's placement-large, south-facing windows allow in natural light that keeps your home cozy and bright. But will this mean your house becomes an oven once summer heats up?

Relax. Choosing a window isn't as difficult as it sounds. Like everything DIY, it takes a bit of education, plus your personal preferences. It's best to start simple: will the window be fixed or operable? Fixed windows are fine in large, open areas-in a living room, high up on a wall or on a door-so long as there is a fire exit nearby and you don't need ventilation. The national building code requires that every bedroom have an emergency exit, so if you're thinking of adding a basement bedroom, make sure the windows are operable.

Operable windows come in many forms, including ones that turn and tilt (common in office buildings), casement windows that open to the side, double-hung (on which the bottom pane slides up into the upper pane), sliding windows and more. In every case, an operable window should have a closure and a locking mechanism that pulls the unit tight against the seal for security and energy efficiency.

Installation insight

Many renovation projects involve replacing an existing window, so placement isn't often a factor you can change, but it does have a bearing on the new window you choose. South-facing windows allow passive solar heating, which means you can collect free heat in the cooler months simply by having a window that faces the sun's rays. During the winter, the sun's elevation is lower at midday, so you'll gain more heat; in the summer months, when the sun shines at a higher elevation, very little sun will hit the south-facing windows, which means your home won't turn into a sauna. (Overheating tends to occur from unshaded west-facing windows.) So, if you are replacing or adding windows, consider a larger size for south-facing walls, and think about installing awnings or eaves over westfacing windows.

Installation can be tricky, especially with higher-end windows, for which performance depends on a tight fit with zero defects or cracks. Obviously, all windows must be installed square, plumb and level with shims and spacers. Most mistakes happen once the window is roughed in. Here's where insulation installation is key: any cracks or gaps will allow warm air to escape and cool air to penetrate your home. Also, warm air contains water vapour, and if this is allowed to seep into the exterior wall, you'll soon develop a condensation (read: mould) problem.

Most contractors agree that injected foam is the best insulation material for sealing windows. Because the foam begins as a liquid, it fills every nook and cranny, whereas traditional fibreglass insulation-the pink stuff-doesn't always fit properly, especially when it has to be torn and fitted into tight spots and around wires and piping. That said, spray foam insulation has to be injected carefully: overfilling can distort the window frame and cause the glass to jam or crack.

Also check that the foam insulation is compatible with the window frame, be it vinyl, wood, aluminum or fibreglass. When foam is used with a vinyl or aluminum frame, for example, there's a possibility the bond between the foam and the frame will break as a result of the frame's contraction and expansion. In any case, it's best to ask the window supplier before firing up the spray foam.


Glass and glaze

When shopping for windows, you'll come across single-, double- and tripleglazed units, which is a fancy way of describing the number of panes of glass that make up the window. More panes equal more energy efficiency. As a rule, never go below double-glazed windows, and choose triple-glazed if your budget allows for it.

Besides the glass itself, many window manufacturers tout special coatings and inert gases that aid in efficiency. Clear glass transmits the most solar energy into a building, and glass with a low-E coating-a microthin finish with metal oxide that reflects a large percentage of heat-allows in heat from the sun and prevents heated or air-conditioned air from leaving the room, much like a Thermos. There are other types of coatings, such as the grey, green or bronze tinting popular on office-building windows. For residential use, low-E is usually the best choice for efficiency and aesthetics. The Ontario building code is now calling for all new windows to have low-E coatings, and, sooner or later, this rule is likely to spread through the rest of the country too.

Double- or triple-glazed windows are made even more efficient with the insertion of an inert gas, such as argon or krypton, between the panes. Both gases are colourless, odourless and non-toxic. Whereas a low-E coating reduces radiant heat loss (from the sun), inert gases reduce heat loss from convective sources (the furnace). Also, like low-E coatings, inert gases reduce summertime heat gain.


The different types of window frames

There are four main types of window frames: wood, vinyl, aluminum and fibreglass. Each has its own pros and cons. But there are general differences, and each one is worth considering-depending on placement and budget.

Wooden window frames offer classic looks with energy efficiency. For those who want the warmth of a wooden window frame inside their homes- pine, oak or maple that can be sanded, stained or painted according to taste. Wood frames perform well in extreme heat and cold, making them wise choices for Canadian seasons. But with wood comes more maintenance (sanding, painting) to protect exterior surfaces against erosion by the weather. If not protected from moisture, wooden frames can warp, stick, crack and rot. But with simple, yearly care, your wooden frames should last a lifetime.


Vinyl frames are the most popular choice amongst homeowners. Made from rigid polyvinyl chloride (PVC), vinyl frames provide thermal protection without the maintenance required of wood. Strong and lightweight, vinyl window frames are generally less expensive than those with wooden or fibreglass frames. If you don't mind the look of vinyl, which can't be repainted to match your interior decor, this is a smart choice. Vinyl frames are also good for areas of high moisture (such as bathrooms or kitchens) because they wipe down easily and don't retain moisture like wood or corrode like aluminum.

Of course, you don't need to make such a choice if you go with combination wood- and vinyl-clad frames-the best of both worlds. Here you get the warmth and insulating value of wood on the inside (paint or stain to your heart's content), while the weatherbeaten exterior is protected with versatile, maintenance-free vinyl. The catch: these windows tend to cost a bit more. (You can also buy combination frames with wood and fibreglass, or wood and aluminum.)

Aluminum frames are very durable, lightweight, paintable and are cheaper than other materials. They also require little maintenance. The problem: aluminum doesn't hold heat and contributes to condensation around the edges of the pane. Plus, expect corrosion if left unpainted for more than a year. Another problem: the paint job will look significantly different than the rest of the house, simply because painted aluminum looks like, well, painted aluminum rather than wood.

Composite and fibreglass frames are the new kids in town-at least, in residential applications. Because of this, the window sizes and styles are limited and the cost is higher. Still, composite/fibreglass

combines the strength of aluminum with the insulation values of wood or vinyl. These frames are resistant to warping and rot, and they can be painted to match any interior or exterior. You should expect to pay double the price of vinyl frames.

Choosing the frame is the biggest decision with windows. Much comes down to personal preference, but keep in mind: a cheaply made window will need to be replaced much sooner than one that costs more up front. Similarly, energy-efficient models may cost more now, but you'll save in heating and cooling costs over the next year or so. As for aesthetics, that decision is up to you.



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