Is your home energy efficient?

Zoomer | July 1st, 2007

We all hear a lot about reducing our “environmental footprint” – the amount of energy that we consume and the amount of waste that we produce. One of the best places to start is in our homes, ensuring that they use energy as efficiently as possible. Here are some of the ways to look at efficiency and what to consider in choosing or renovating a home.

What type of housing?
Before looking at materials and energy ratings, many people choose to look at which type of housing might both suit them and reduce energy use. Choosing a smaller condominium where one can walk to local shops is generally less wasteful than a larger home in the suburbs – but those aren’t the only choices. Situating a house where it is shaded in the summer, for example, can reduce air conditioning costs considerably.

And if purchasing a new home, consider ensuring that it is a R2000 rated home. This is a voluntary programme where builders construct homes to certain efficiency standards. More information is available here.

But if moving or building from the ground up is not an option, here are some ways to make your home more energy efficient, particularly if you are thinking of renovating.

Building envelope
The building, or thermal, envelope is everything about the house that shields the living space from the outdoors. It makes sense that most energy loss would happen at these points. Here are some specific ways builders and renovators are making this envelope more efficient:

• Increasing the amount of insulation in the walls and roofs. This is one of the simplest ways to make a big difference in your home’s efficiency – and your heating and cooling bills.
• Using energy-efficient windows (often double-glazed), and situating them appropriately. The typical home loses over 25 per cent of its heat through windows. Even with the newer better windows (and many are much more efficient), placement of windows is an important consideration. And in general, the best sealing windows are awning and casement styles since these often close tighter than sliding types.
• Sealing all openings through which air could leak in or out. One area to look at is around lights suspended or set into a ceiling which has an attic above.
• Reducing “thermal bridging” where non-insulated materials conduct heat outside the home.
• Ensuring there is a good vapor barrier to keep moisture from condensing in the wall

Passive solar design
Passive solar design in most homebuilding involves orienting windows and even the building itself to make best use of the sun. In Canada this generally means:

• Placing fewer windows on the north side
• Placing more windows on the south side
• Providing window shading on the south to keep rooms cooler in summer

Heat, air, and cooling
While the building envelope and passive solar design both impact on heating and cooling, there are additional ways to make these more efficient. High-efficiency furnaces and air conditioners may seem expensive, but they can significantly reduce fuel and electricity costs. A heat pump system can make both more economical.

Ventilation is also an important factor. Air-to-air heat exchangers capture the heat from air being exhausted to the outside, and use it to pre-heat fresh air being brought into the building.

Lighting and power
Well-placed windows also help to conserve power by encouraging the use of natural light during the daytime. And the new energy-efficient light bulbs – which will become mandatory in Ontario – reduce energy consumption considerably. Motion detectors and lights that only come on in the darkness can also minimize unnecessary use, particularly on outdoor lighting fixtures. Many new garden lights also come with solar cells in order to provide electricity.

Choosing energy efficient appliances is also a must for anyone who wishes to conserve energy in the home. The EnerGuide rating system makes it easier to select an efficient appliance, but other considerations include not purchasing appliances that have excess capacity – a large fridge, for example, can be wasteful if you normally do not keep much food in the house. Natural Resources Canada provides a guide online here.

Water conservation
Water costs in housing can also be minimized through conservation measures. Some simple ways to minimize water use includes installing low-flow toilets and showers, and capturing rain water from roofs in rain barrels to use in maintaining your lawn and garden.

But another technique involves designing the home so that so-called “grey water” from showers and washing machines is used in toilets. This is more advanced design but can be an excellent way to conserve both water used and the amount of water going into the sewer system.