Blog Post Monday 11 May 2020
Energy efficient windows minimise heat loss and gain throughout winter and summer. They create a more energy efficient home that’s cheaper to run. So how much energy are you losing through your windows and how much might you save by upgrading your windows?
You might not think of your windows as major factors for energy efficiency, but heat gain and loss through your home’s windows account for around 25% to 30% of residential heating and cooling energy usage. As much as 40% of your heating energy can be lost and up to 87% of your home’s heat gained through your windows. In other words, the more energy efficient your windows, the less you’ll end up spending on heating and cooling your house.
Energy efficient windows use specially designed glazing and framing materials to limit heat gain and loss. In Australia, the Window Energy Rating Scheme rates the energy-related performance of windows according to the Australian Fenestration Rating Council’s guidelines.
The materials and design of energy efficient windows reduce unwanted heat gain during summer. In the cooler months, they reduce heat loss by reducing the level of heat passing through. Energy efficiency can also be based on how much light and air passes through the glass. Combined, these factors can reduce how much cooling and heating your house needs to stay comfortable.
A range of different factors go into making windows energy efficient:
As a rough guide, double-glazed windows can cost around $1,350 per square metre. Extras like specific frame materials, low-e coating, gas fills, and spacers could raise the price.
Local window suppliers might carry product lines that are energy efficient. You could approach them directly before contracting with an installer. Alternatively, you could speak to glaziers or building contractors and ask them to recommend a suitable product for your home.
Your installer might need to be a licensed glazier. Make sure you work with a licensed, experienced installation professional who can complete the installation work, including flashing and air sealing, according to the manufacturer’s instructions. This is vital for maintaining the warranty and ensuring your windows achieve their intended efficiency. Speak to your contractor about their experience with the specific window system you’re installing as well as the material of your home’s construction, whether it’s wood, brick, masonry, or something else.
You could save as much as 25% on your energy consumption by upgrading to energy efficient windows.
How much energy and money you’ll save could vary depending on factors like facing direction, your local climate, and the size of your home. However, with double-glazed windows and doors, you and hundreds of dollars a year and so thousands of dollars on your energy bills over several decades.
Homes that already have double-paned windows might see modest savings with new energy efficient windows. However, if you have single-pane windows with worn, leaking frames, you’ll likely notice significant energy savings with an upgrade. Although the initial outlay might seem high, energy efficient windows could well be worth the cost by reducing your home’s heating and cooling costs.
At the same time, they can contribute to a better temperature-regulated, more comfortable residence. You’ll have a more environmentally friendly residence, boost your property value, and protect your interiors from sun damage. They also offer noise-reduction benefits and they require less maintenance than standard windows due to the reduced condensation.
If you don’t want to replace your existing windows, you have other options for minimising heat gain and loss. You could apply a solar-heat-reduction film to your existing windows. These are typically thin polymer films that incorporate a reflective metal layer or absorbing dye to minimise heating trapping. Additionally, you can invest in some energy-efficient window coverings like blinds and curtains.
Ask the manufacturer and installer about multiple glass panes, frame material, low-e coating, gas fills, and spacers. Additionally, look for windows with a rating (0 to 10 stars) from Window Energy Rating Scheme (WERS). The more stars, the better the window’s thermal performance. Additionally, the WERS percentage figure tells you the window’s comparative energy rating. This means having a window system with a 49% heating percentage allows your heating system to work 49% less compared to a basic aluminium single-glazed product, to maintain a comfortable temperature.
Also, check the U-value (Uw) (relating to heat conductivity) and Solar Heat Co-efficient (SHGCw) (relating to sunlight flow) ratings. All windows in Australia need to fulfil minimum standards for these under the Build Code of Australia. The lower the U-value, the better.
Your home’s windows don’t just provide you with a great view and natural light; they have a key role to play in the comfort and temperature regulation of your home and impact your heating and cooling expenses. Investing in a windows upgrade, whether by making simple changes to existing windows or with a complete replacement, can significantly reduce how much you’re paying for heating and cooling, with the added benefit of a more comfortable home with a higher market value.
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