Windows can be one of the most important components of any home. In addition to enhancing the style and beauty of a house, windows provide fresh air and ventilation, bring sunlight into interior spaces and keep harsh weather outside where it belongs. Thanks to technologies developed over the past few decades, new windows can also improve the energy efficiency of a home and significantly lower your monthly energy bills.

But, purchasing new windows can be a daunting task. So if you're in the market to replace or upgrade your windows, Canada Mortgage and Housing Corporation (CMHC) has a number of tips to help you choose the right windows for your home:

• Window frames come in a wide variety of materials, from traditional wood and aluminum to vinyl and fiberglass. Each material has its own strengths and weaknesses, so be sure to investigate which type is best suited to the local climate and your home before making any final decisions.
• The Canadian Standard Association A440 suite of standards (the window standards) set the performance criteria for all windows sold in Canada, such as air and water tightness, wind load resistance, ease of operation, resistance to forced entry, condensation resistance and screen strength.
• One of the most important criteria for new windows is how well they control air leakage, which can drive up utility bills dramatically. In Canada, windows are rated A1, A2 or A3 to reflect increasing levels of airtightness. If you live in an area with high winds, a higher "A" rating may be a better choice over the long term.
• Water leakage can also be a serious problem for homeowners, damaging interior and exterior finishes and encouraging the growth of mold. Window resistance to wind-driven rain is rated from B1 to B7 to reflect increasing resistance to wind-driven rain penetration. Higher performance ratings are recommended in coastal climates and other areas where wind-driven rain is more common.
• Windows are also tested for their ability to resist wind without warping or blowing out of their frames. Wind resistance ratings range from C1 to a high of C5. C5 ratings are appropriate for windows in some high-rise buildings, or for low-rise buildings in very windy climates.
• Selecting the right glazing (or glass) can also play a key role in the energy efficiency, longevity, comfort and enjoyment of your windows. Triple-glazed windows, for example, can help reduce noise transfer from outside, and tend to be better insulators than double-glazed windows, especially in areas with extreme weather conditions.
• Finally, low-emissivity (or Low-E) windows can also enhance energy efficiency and comfort. Low-E windows have a thin coating of metal oxide on the outside surface of the interior pane that allows sunlight to pass through but filters out UV rays and blocks interior heat from escaping outside.