Windows can be responsible for up to 40% of heat gained and approximately 30% of heat lost in your home, so it makes sense to choose energy efficient windows and skylights.
When thinking about energy efficiency, the window system (the glass and the window frame) is very important. Consider:
- exposure of the window to the sun (orientation and shading)
- positioning (to catch breezes, enable cross ventilation, and maximise or minimise the amount of sunlight you let in).
Minimise summer sun and maximise winter sun by placing windows on the northern side of your home.
Keeping cooler in summer
During summer it is important to ensure that windows do not let in too much heat from direct sunlight. Using tinting and reflective films to reflect the hot sun away from your home can keep your home cooler. External window coverings can help shade your home and internal window coverings can help keep the sun's heat from entering your home.
The easiest way to shade your home is to ensure you have the right sized eaves as this will allow the sun to warm your home in winter while also blocking direct solar heat in summer when the sun is higher in the sky. You can also use plants, shutters, blinds, screens, verandas or carports to shade windows at home.
Use tinting and reflective films to reflect the hot sun away from your home. External window coverings can help shade your home and internal window coverings can help keep the sun's heat from entering your home.
Keeping warmer in winter
In cooler areas of Queensland, open your curtains on northern windows during the day to let in the warm winter sun. Choose windows that significantly reduce heat loss, minimising the need for artificial heating. To keep your home warm, think about double glazing or Low-e glass in your windows which can reduce the heat loss from your house. Double glazing and Low-e glass can also help keep your home cooler in summer by reducing the heat coming in through the glass. This means the airconditioner doesn't need to work as hard.
It's also important to ensure window coverings fit snugly to stop warm air circulating between the curtain and window causing heat loss in winter. Curtains, pelmets and interior blinds are some of the less expensive ways you can save on home heating and cooling bills.
Make sure your windows are sealed to prevent draughts. The type of window system you choose can have a big impact on air leakage and ventilation in your home. Hinged windows, like awnings and casements, generally have lower air leakage rates than sliding windows.
When purchasing glazed windows and doors those with a lower U-value (or rate of heat transfer) will perform better all year round as they will prevent the energy used for heating and cooling from escaping.
WERS is the Window Energy Rating Scheme – a labelled rating system for windows. Rated windows carry a label which certifies that the window has been rated by the Australian Window Association.
The window's cooling and heating performances are rated separately on a scale of 0 to 10 stars - the more stars, the better. These stars indicate the effect the window will have on the energy performance of the whole house.
The Heating Star rating indicates the performance of the window system when heating your house. The Cooling Star rating shows how well the window system performs when cooling your house.
Choosing energy efficient windows can improve your home's resale value, comfort and amenity. For example, in hot areas of Queensland use windows with a high cooling star rating on the western and eastern side of your home to keep the heat out and reduce your cooling costs.
Calculate, compare and save
The Efficient Glazing website is an initiative from the Australian Window Association aimed at allowing consumers to make the best choices when purchasing energy efficient windows and doors. This website allows users to compare different window products against a base window to assess the potential savings that can be achieved by upgrading to an energy efficient window or door system.
Talk to a professional
Speak to an expert in window energy efficiency to help find the best options to reduce your heating and cooling costs. Contact the Window Energy Rating Scheme (WERS) for advice on selecting a suitable window product.
To find window manufacturers with energy rated windows visit the Window Energy Rating Scheme website and use the members search tool.
Where can I find more information?
Our booklet, The energy sense home (PDF 4.9 mb), provides advice on simple choices to help you make your new home the best it can be.
Visit the WERS website for more information on energy efficient windows and how to select windows. You can also speak to a window manufacturer or builder to learn more about current window options available.
For more information, the Queensland Government has produced a fact sheet on Energy saving for windows.
Visit the YourHome website to find more tips on windows for your home and how to save energy and money.