Aussie summers can be brutal and in some places living without air conditioning simply isn’t an option. Unfortunately, this air conditioned comfort comes at a cost. For the average Australian home, heating and cooling can account for up to 40% of household energy use. And that percentage can be even higher in particularly hot areas.
However, there are cheap and easy ways to reduce your reliance on air conditioning, save money on your power bills and improve your home’s carbon footprint.
Passive design involves making use of natural sources of heating and cooling to minimise heat loss and gain in your home. Best implemented at the design and construction stage, passive design makes use of things like orientation, natural shading, heat storing or reflecting materials, and natural breeze flows to keep the structure cool and make it more energy efficient.
Passive cooling strategies can also be implemented in homes that have already been built. And while air conditioning systems can cost a lot to run and maintain, these passive cooling tips won’t cost much beyond the initial installation and will save you serious money in the long run.
So let’s look at 5 tips to help you passively cool your home and save money on your power bills.
- Glazing Treatments
Windows can be responsible for more than 80% of a home’s heat gain. So improving the thermal performance of your windows can significantly reduce your home’s reliance on air conditioning. The two most common glazing treatments are window tinting and double glazing.
Professional window tinting involves adding a tinted window film that filters out UV rays and the sun’s heat. Tinting is a great option for east- or west-facing windows where it can be difficult to shade the low angle of the sun. With tinting, you can also reduce the amount of heat gain and sun glare without obstructing the view from the windows.
While tinted windows will prevent a lot of the sun’s heat from entering the house, the windows themselves will still get hot, and this heat can transfer inside. This is where double glazing can help. Double glazing features two panes of glass separated by a sealed pocket of air or inert gas. Since air is a poor conductor of heat, the outside pane of glass can heat up, but that heat won’t be conducted inside. Double glazing will also provide extra insulation, helping to keep the cool air inside.
Window tinting can be professionally applied to most existing windows. However, only specialist glaziers can retrofit double glazing to existing windows. While a combination of tinting and double glazing is a great option for passive cooling, it can be pricey, especially if you need to replace your windows.
Shading your house from the sun is another great way to reduce heat gain and lower cooling costs. The more direct sun that your home absorbs, the more work needs to be done to cool the interior of the home. Shading the home means that the shade blocks or absorbs the heat before it reaches your windows, walls or roof.
Since windows are responsible for the most heat gain in a house, shading windows should be the first priority. There are a range of options for shading windows including eaves, pergolas, louvres, shade sails, and even plants.
Shading can also be used to minimise the force of the sun on east and west facing walls and the roof. When planning passive shading you want to carefully work out the summer sun angles to determine where shading will have the most value.
Strategic planting for shade is a great natural option for passively cooling the home. Deciduous trees, vines and shrubs are a great option for blocking out the sun in summer while letting light through in winter. Ground cover plants can also absorb heat, lower temperatures around the house and reduce glare and reflected heat.
- Update Insulation
Insulation is a vital component of any passive cooling project. Insulation creates a barrier to thermal transfer, capturing heat before it can enter the interior of the house. Quality insulation will significantly lower heat gain, reducing the need for air conditioning to cool the home.
If your home has old insulation, it might be worth updating it for maximum benefits. Have an insulation professional assess your property to determine the type, amount and placement of insulation that is best suited to your type of home, as well as your location and climate.
Natural air movement is an essential part of passive cooling. Channeling natural breezes through the house can help to dissipate heat by removing stagnant air and reducing humidity.
While good ventilation should be factored in at the house’s design stage, it can be enhanced in existing properties through the strategic use of doors, windows, skylights, louvres, vents and ceiling fans.
Natural ventilation works best when coordinated with the weather. You should minimise outside ventilation during the hottest parts of the day and try to maximise ventilation at night when the outside air is coolest. This can help to dissipate the heat that has been absorbed during the day and prevent the build-up of heat over multiple hot days.
- Natural Evaporative Cooling
As water evaporates, it absorbs heat and cools the air. Strategic placement of water features like ponds, fountains or misting sprays can help to cool the air around and inside your house. Combining water features with the breeze creates a natural air conditioning effect where the air is cooled as it passes through the evaporating water. This technique works best in low humidity areas. When using this technique, it’s worth considering how you’re going to source the water to ensure you don’t end up wasting water.
Passive cooling is a great way to keep your home cool in summer, save money on your power bills and reduce your home’s carbon footprint. With a little creative planning, you can reduce reliance on your air conditioning while keeping your home cool all summer.