Canada Mortgage and Housing Corporation

Canada Mortgage and Housing Corporation

October 12, 2012 12:40 ET

Window Awnings for Better Cooling

OTTAWA, ONTARIO--(Marketwire - Oct. 12, 2012) - Walls with large window glazing areas are great for letting natural light into your home. Energy efficient south facing windows can even reduce your heating costs in the winter by letting in the sun's warm rays - a concept known as passive solar heating. However, too much sunshine in the summer months can make your home uncomfortably hot and may increase your air conditioning energy costs. Fortunately, you can control how much sun enters your home with outdoor shading devices such as window awnings and screens.

Window coverings have been used since ancient times to protect against the elements. Interior curtains and blinds were used to protect furniture and carpets from fading, but studies show that they are not effective in keeping the heat out. Outdoor awnings can protect against sun, rain and snow and in the early part of the last century both retractable and fixed awnings were a common feature on houses and storefronts. Awnings later fell out of fashion as air conditioners became more common and styles and tastes changed. However, rising energy costs and concerns about the environment have lead to a renewed interest in this "old" technology.

Do awnings save energy?

Recent research, undertaken at the Canadian Centre for Housing Technology, found that awnings helped reduce cooling loads by approximately 15 per cent during the summer season for a savings of 401kWh or about $40 to $50 per year. Energy savings will vary depending on house characteristics and homeowner lifestyle choices (e.g. open vs. closed windows during the day) and the cost of electricity.

The study also found that awnings caused room temperatures to be lower, both in rooms with awnings as well as those without due to continuous air mixing from the furnace fan. As a result, the air conditioner went on less frequently and worked more effectively in keeping the whole house cool.

Even on bright sunny days, awnings can reduce interior lighting to the point where homeowners may wish to turn on a light for reading or other activities requiring plenty of illumination. However, the energy used for energy efficient lighting is much less than for interior cooling so you will still save energy overall or you may wish to retract your awning - the choice is yours.

Modern shading devices come in many different designs, styles, colours, and materials. From the conventional fixed aluminum or fibreglass awning, to the modern sail style in colourful, water resistant fabric. Retractable awnings are available in a range of designs including: lateral arm awnings that can cover large spaces making them especially useful for deck or patio covering; and side or drop arm awnings which can be raised or lowered to cover as little or as much of the window as desired. Retractable awnings are available in manual and fully automated models including designs that detect high winds and retract the awnings before winds can damage them.

A less common outdoor shading device are Solar Shade screens which are attached on rollers over the window and roll down like interior blinds. These are well suited to blocking the sun's rays and are commonly used in warm Mediterranean countries, but can block the view to an unacceptable level for some homeowners.

No matter what type or style you choose, external shading devices can help keep your house cool during the summer months and reduce your energy bills.

For over 65 years, Canada Mortgage and Housing Corporation (CMHC) has been Canada's national housing agency, and a source of objective, reliable housing information.

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