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Controlling Sunlight

Direct sunlight on windows and the exterior of your building can significant increase the temperature of your members' homes. There are several ways to mitigate this sunlight, many are low cost.

  • Windows
    • Single-paned glass is a terrible insulator; double- and tripled-paned glass is much better. If your buildings still retain older glass, consider replacement even if there’s still life left in the windows. Improved windows will help keep desired heat in and unwanted heat out, especially when combined with appropriate coatings.
    • Coated glass (low-e glass) can block more of the non-visible radiation that comes from outside, reducing heating costs and offsetting, over time, the cost of new window installation. Members may even save money as well as reduce overheating, and there may be government programs to help with this kind of capital upgrade.
  • Colour
    • Choosing colours for your buildings that reflect rather than absorb light can help. Some co-ops with flat roofs use tar-over-gravel or other materials with dark surfaces that get very warm in direct sun.
    • White roofs” can reflect 85% of the light hitting them, helping reduce unwanted heating.
  • Exterior Shading:
    • Just as trees provide natural shade, buildings can be designed to screen out unwanted sunlight and heat.
      • Awnings and other exterior shades for windows, such as shutters or overhanging roofs can be considered, especially if you’re gearing up for major envelope work. (If you’re under warranty for an envelope, be very careful before doing anything that could damage your buildings’ exteriors).
      • Some outside shading features can even be connected to automated systems to regulate the amount of shading provided, but even stationary systems can be designed to let more (low-angle) light pass through in winter than in summer.
  • Interior Shading
    • Blinds and window coverings can help regulate internal temperatures.
    • If your co-op doesn’t provide window treatments that can reflect light back outside, consider adding that component to your co-op’s capital or renewal schedule. Window insulator films are also an option.
    • Even if your co-op forgoes policy or capital work in this area, you can still provide members with information about how behaviours—like keeping blinds closed in summer—can help moderate temperatures.