Eco-responsible doors and windows Tips

Replacing doors and windows with new, airtight models with good thermal insulation is a good way to save energy and reduce greenhouse gases (GHG). Old exterior doors and low-performance windows can account for up to 30% of the heat loss from a home during heating season (Office of energy efficiency). Likewise, inefficient south-facing windows can heat up a home in summer by letting in too much sunlight.

The efficiency of doors and windows is described using the heat transfer rate (U-value) and the energy rating (ER). The lower the U-value, the slower the heat transfer from the hot side to the cold side, and the more efficient the door. The higher the energy rating (ER), the more leakproof the door. It’s important to choose windows suited to the local climate: U-values and ERs are different in different climate zones. You can find out more in store or at the Office of energy efficiency website.

Our recommendations :

• Choose ENERGY STAR® rated doors: they meet the highest energy efficiency standards, are more airtight and more durable than traditional models. Their energy performance is up to 40% higher than traditional doors thanks to the following features:

  •   Double or triple glazing with an insulation layer between the panes. This area is filled in an inert gas (argon or krypton) that is heavier and less conductive than air, and therefore more insulating.

  • Glass covered with an invisible metallic coating, also called low-emissivity or low-E glass.

  • Low-conductivity insulating spacers that reduce energy loss and keep the edges of the window warmer.

  • Insulated door and frame.

• Choose ENERGY STAR® rated windows: they meet the highest energy efficiency standards, are more airtight and more durable than traditional models. Their energy performance is up to 40% higher than traditional windows thanks to the following features:

  • Double or triple glazing with an insulation layer between the panes. This area is filled in an inert gas (argon or krypton) that is heavier and less conductive than air, and therefore more insulating.

  • Glass covered with an invisible metallic coating, also called low-emissivity or low-E glass.

  • Low-conductivity insulating spacers that reduce energy loss and keep the edges of the window warmer.Insulated sash and frame.

• Unpleasant overheating in summer is often the result of south-facing windows, but can also be caused by eastern and western exposures, which catch the early morning and late afternoon sun. These windows should be properly shaded by trees, curtains or shade-screens (over the windows) to reduce the need for air-conditioning.

• When doing an extension or major renovations, putting more windows on the south side rather than the north side allows you to take advantage of passive solar heating. In winter, the noonday sun is far lower than in summer, and it heats rooms by shining into south-facing windows. To let in the most passive solar energy, these windows should not be low-e (low emissivity glass). Since there is no direct light from the north, windows on that side cannot benefit from solar energy, and are therefore one of the thermal weaknesses (insulation gaps) in the house in winter. Windows on this side of the house should be low-e to keep the heat inside. Plan the location of doors and windows carefully to reduce air-conditioning costs in summer and take advantage of the sun as a source of heat in winter.

did you know ?

In winter, a 10-square-foot window facing south can provide as much heat as a 1000-watt baseboard heater. (NRC Institute for Research in Construction)

To reduce resource use, choose high-performance windows with frames made of wood, aluminum, fibreglass or a mixture of these materials. Among the different types of windows, the most airtight are casement windows, where all four sides of the sash leave the frame when the window is opened using a mechanism that holds the sash.

Our recommendations :

• Casement (or “crank”) windows offer the best airtightness because of their double compressed weatherstripping, which can be replaced if it breaks. Hanging and sliding windows have to slide along the frame, which prevents the use of such high-performance weatherstripping. The airtightness of newer window models has improved remarkably, and adding a plastic film in winter allows them to achieve efficiency similar to that of a casement window.

• Pay special attention to basement windows: The window well should be below the level of the window, filled with gravel and equipped with a drain connected to the French drain, to allow water to drain quickly.

• Windows are made of many different kinds of materials. Although each has its own advantages and disadvantages, the first factor to consider is its durability, to extend the lifetime of the product:

  • Aluminum is very durable, requires little maintenance and offers the best rigidity, which means the windows can be bigger. It is highly heat conductive, however, so the structure of the sash must be well insulated, with polyurethane foam, for example.

  • Fibreglass is very durable and rigid, requires little maintenance and offers good energy efficiency, thanks to sashes injected with polyurethane foam. It can also be covered with aluminum on the outside and wood on the inside, but very few models offer this option.

  • Wood is warm, durable, and rigid, and it provides good insulation, but it demands regular upkeep to avoid mildew and maintain its appearance. To avoid this problem, the outside of the frame can be covered with PVC or aluminum. The covering must be perfectly leaktight to prevent the wood from rotting.

  • Although PVC windows are affordable, easy to maintain and offer good insulation, they do have some shortcomings. Poor quality PVC can emit chlorine into the air in the home and it degrades under UV rays. It is important to choose high-quality PVC with a thicker profile. PVC is also less solid than metal: the frames are often wider, reducing the glass surface. The production and disposal of PVC can release toxic pollutants into the environment as well.

Exterior doors, with their dual function of barrier and opening, should be airtight and watertight, well insulated and made of highly resistant materials to delay wear and reduce energy consumption and GHG production.

Our recommendations :

• Exterior doors often include decorative windows, but these reduce the energy rating of the door. In this case it is especially important to choose a door that is well-insulated, with polyurethane foam, for example, to avoid condensation and frost on the glass.

• Make sure the selected door is equipped with good weatherstripping to avoid air infiltration.

• Exterior doors are often composed of several different types of materials. The exterior layer determines the type of door. Choosing a resistant material is the best way to increase the lifespan of the door. Here are a few options:

  • Steel doors are rigid, durable, easy to maintain, airtight and they provide excellent thermal insulation. They can feature decorative windows, but this reduces the energy rating of the door.

  • Fibreglass doors are moulded around a central core of polyurethane. They are resistant to cold and damage and also require little maintenance. They can also be finished to look like wooden doors.

  • Modern wooden doors also offer good airtightness and are generally made of panels of veneered wood sandwiched with insulating foam. Solid wood doors offer the insulation value of wood, but they are not the sturdiest doors. They can be easily damaged and require more maintenance than other types of doors.

  • Aluminum is often used to make the frames of patio doors, since it is light, sturdy and requires little upkeep.

  • PVC is light, rust-resistant, easy to clean and requires little upkeep. It is often used to make patio door frames, but the production and disposal of PVC can release toxic pollutants into the environment.

The space between the wall and the door or window frame must be well insulated to prevent air infiltration, which will reduce the energy rating of the installation. To do this, you can use neoprene gaskets and low-expansion urethane foam.

Use low-emission paints and stains that are free of volatile organic compounds to maintain wooden window frames and doors.

Recycle your old doors and windows: you can take them to a building materials recovery centre or ecocentre. Do your best to avoid sending it all to landfill.