For under $10,000 you can make significant changes to ensure your home stays cool during hot summer days. “Anything over 250ºC is considered overheated,” says Eco Design Advisor Ian Mayes. “We look to passive solutions first because they’re the best and the least expensive option.” If your budget is higher, you can read about mid-range or high end cooling options.
What are passive cooling and active cooling?
There are two ways to cool: passive and active. “Passive cooling means keeping your home comfortable throughout summer without using mechanical assistance,” says Smarter Homes. It includes shade sails, insulation and deciduous tree plantings rather than ‘active’ solutions that rely on purchased energy such as heat pumps and air conditioning.
“A lot of people don’t have a heat pump or can’t afford to run it. In addition, heat pumps are efficient at heating, but not so effective when it comes to cooling,” says Ian. “A passive solution is simple – insulation, shade and ventilation.”
How much does insulation cost with a basic budget?
“You need to insulate really well,” says Ian. “If you’ve already got insulation, a top up will set you back about $2,500-$3,500 and underfloor insulation will cost around $2,500.”
Dominic Hollands of Refresh Renovations agrees. “Roof and ceiling insulation should be your priorities, iron roofs particularly heat up a lot,” he says. “A lot of people think insulation is just for warmth, but it works to keep your home cool also.” Our experts suggest using higher levels of insulation than the Building Code minimum for best results.
How much does it cost to add a shaded area to my home?
“A shade sail, a couple of posts and a bit of concrete from Bunnings can create a shaded area for about $200,” says Ian.
“The idea is to block off the northern sun and the western afternoon sun, which is charged with heat energy. A shade sail is a great solution as it’s moveable. Moveable or removable shading is optimal as you don’t want to stop solar gains in winter.”
Another cost-effective tool is strategically planted deciduous trees, which lose their leaves in winter.
How do I cool down my house?
Opening doors and windows and letting the air-flow through is part of cooling 101 in temperate climates, however security can be an issue.
“Safety catches are not expensive (about $20 each) and work very well,” says Ian. “They allow you to keep the house ventilated all day even when you’re not at home.”
Dominic Hollands also recommends adding a lockable security door. “They allow you to keep air flowing without compromising security,” he says. “Approximate costs range from $900 off the shelf to $1300 for a custom design.”
Eco Design Advisor Nelson Lebo -who holds a PhD in Science Education and hails from North America- suggests an inexpensive and effective option. “You need to think of your home like an insulated box, which means treating it like a wind tunnel at night and a chilly bin during the daytime.”
“During the design process make plans to put screens on one window per bedroom,” he suggests. “Then at the opposite end of the home place a fan in a window pointing outwards.”
It seems like an oxymoron but it’s common practice in the heat of North America where ‘window fans’ can be purchased that are designed to fit snuggly in window frames and provide inexpensive cross ventilation.
“As soon as the outdoor temperature drops in the late afternoon or early evening set the fan going and keep it going all night long. This exhausts the hot air that’s built up during the day and draws the cooler air inside. In the morning shut off the fan and – as much as you can tolerate – keep windows and doors closed to keep the cooler air in and the curtains closed to stop the heat of the sun from reaching deep inside.’’
‘’A fan might set you back $20-$30 and a typical fan -say, 40 watts- costs about one cent per hour. A 50 watts fan costs one-and-a-half cents per hour to run. It will cost you about 10-15 cents to run it all night drawing in free cool air. A fan’s motor is the opposite of a generator so essentially what it’s doing is unwinding electricity. It’s the most efficient way to use electricity.”
To sum up, most of your investment should go into insulation and landscaping solutions to create shady areas. Investing in thermal lined blinds and curtains would also help keep temperatures lower particularly if they are closed on the northern side of the house during the day and the western side during the afternoon.
Depending on your budget, you might like to read about cooling options with a Mid-range budget or a High end budget.
Note: prices are rough approximations only, and Refresh Renovations cannot be held accountable for their accuracy. All prices in this article are exclusive of installation costs and any variations.
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