Replace those old windows with these better options
Time to lay your old windows to rest? High-performance windows employ multiple panes, often with insulating gas (argon or krypton) in between. They also come with a Low-E (low-emissivity) coating. This microscopically thin, metallic layer curbs radiant heat flow while admitting light, reflecting solar heat in summer and holding indoor heat in winter. Factory-applied tints also keep summer heat out, but they’ll block some light—perhaps a good thing on western exposures. Opt for wooden frames and sashes (sustainably harvested—look for third-party certification), as they transfer less heat than their aluminum counterparts.
A window’s U-factor rates how well it resists heat transfer. The lower, the better: Triple-glazed units can score as low as 0.15, while some older single-pane versions rate a whopping 1.2.
High-performance windows improve comfort, save energy, and add resale value, but can cost almost 50 per cent more than standard replacement windows. Less pricey is to retrofit existing windows. Adding storm windows, inside or out, traps air between the panes, providing insulation and wind protection. Sun control films block heat to keep the cottage cool in summer. Many are tinted or reflective, and cut some light; others help trap room heat in winter. Low-tech strategies include weatherstripping and caulking to reduce air leaks.
To learn more
• Rocky Mountain Institute’s Home Energy Brief on windows
• Solar control window films
• Loewen Based in Steinbach, Manitoba; wood frames incorporate 88 per cent sustainably harvested wood.
• Pella Pella’s Impervia windows are made of a fibreglass composite that withstands severe weather conditions.
• Milgard All windows come with a standard Low-E coating.
• Velux Skylights with standard Low-E coating and argon-filled double glass.
• Sunoptics Skylights with prisms that directs a soft light down to the room rather than bright spots commonly associated with other skylights.
• Landmark Window Systems An Ontario dealer of replacement windows, many with high-performance features.
Solar control window films
• 3M Sun Control Blocks up to 78 per cent of heat from entering; offers clear and tinted films, with tinted films slightly changing the colour and appearance of the glass. For an Ontario dealer, see Franklin Tint.
• V-Kool These clear films do not change the appearance of the glass.
• CPFilm Llumar solar control film in different hues and tints.
This article was originally published on June 1, 2008