Feature

Cool retreats

Green Lifestyle magazine

With summer well and truly here – and particularly in light of climate change – finding ways of beating the killer heat by cooling down your home is an important task.

cool-retreats

Canvas awning shades the entire front verandah of this small home.

cool-retreat

Large wrap-around verandahs go a long way to keeping the heat at bay by shading windows.

Cool home

A deep verandah cools the house by shading windows and walls.

Credit: Image courtesy Secret Gardens. Photo: Jason Busch.

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When I think of heatwaves, I remember pale, prim aunts in silken dresses closing the wooden shutters and lying on settees in high-ceilinged rooms in my grandparents’ Victorian house. On the outside walls, there is a dance of shadows from the interlocking umbrellas of stone pines, palms and oaks, while deep verandahs shade the living areas.

Sheltered inside, the genteel aunts sip iced water or homemade lemonade, some fanning themselves. If the heat gets too relentless, they retreat to the dim, cool, book-lined cellar below the house.

With Australia and the world experiencing increasingly intense heatwaves due to climate change, scientists say we need to adopt the cooling strategies used by our grandparents and add a modern twist. That includes
creating “cool retreats” in our houses where we can live
at the hottest times of year.

Future temperatures:

Predicting and coping with extreme heatwaves was a focus of the recent Climate Adaptation 2013 conference in Sydney, organised by the National Climate Change Adaptation Research Facility (NCCARF). Professor Nigel Tapper, Personal Chair in Environmental Science at Monash University and a presenter at the conference, says the number of heatwave days in Australia’s capital cities are expected to rise sharply between 2020 and 2040. “The intensity is increasing and the length is increasing so you don’t get the cooling off overnight that you expect to get,” he adds.

Tapper was among a group of researchers, led by Dr Margaret Loughnan, who calculated the “threshold temperatures” above which urban Australians are more likely to get ill or die during extreme heatwaves. They based their figures on actual daily temperatures in cities at which “excess heat-related illness and deaths occurred” between 1999 and 2011.

The group drew up “heat vulnerability maps” of capital cities, showing the suburbs where people are most at risk. You can look up your suburb on the maps to find if you are in a high risk area – www.mappingvulnerabilityindex.com.

Here are some of the recommendations for cooling the home that were presented at the conference. They’re strategies you can adopt right now in preparation for the summer heat. They’ll also help you save on energy bills.

1. Create a cool retreat

Reconfigure your home to include a cool zone, or allow for it when building a new home. This could be a room or basement area with better insulation, ventilation and shading that can be cooled more energy efficiently. Air conditioning only a small self-contained space within a home will save on electricity costs.

2. Plant some trees

Plant large, fast-growing deciduous trees or grow vines on a trellis to shade your house. The trees should grow tall enough to shade the walls and the roof and be planted on the west or north sides of the house to be most effective. Deciduous creepers can be used to cover sunny walls.

Have a look at neighbouring homes and at trees already on your property to see how shadows fall through the day – in particular, what size tree casts a shadow long enough to reach from the proposed planting spot to the wall or roof area that needs shading. It’s a good idea to consult a couple of local nurseries on the most suitable plants for your area and situation as different nurseries stock different plants. Note: try not to plant trees so close to boundary fences that they will shed leaves and other debris in adjoining yards. Planting something that shades your neighbours’ solar panels could also cause conflict down the track.

3. Install awnings or blinds

Install external awnings or blinds to shade windows. If you are renting and cannot persuade your landlord to add external shades or awnings, install internal blinds or use thick curtains with white or reflective linings.

4. Go for eaves

If you’re building a new home, opt for one with eaves. Ideally they should shade windows completely in summer but allow warming sunlight into rooms in the winter months.

You can add or extend eaves on existing dwellings to shade north-facing windows, depending on the roofing material. Roof tiles can be pulled up and rafters extended before relaying the tiles.

5. Use energy-efficient air conditioning

Consider installing a six-star energy rated air conditioner. If your existing air conditioner is more than 10 years old, your energy bills could be twice as much as what you’d pay with a new system. Before acting, get an energy assessor or air conditioning specialist to test the energy efficiency of your existing system.

6. Cool your roof

Reflecting solar heat away from the roof and insulating the ceiling are two of the most effective ways of cooling your house. Paint a tile or metal roof with reflective paint and attach reflective foil to the underside of the roof to make it more heat reflective.

Make sure your ceiling has proper thermal insulation – anything from glasswool batts or blankets to natural wool underlay or recycled loose-fill cellulose fibre.

Did you know?

- A recent study showed that in Australia 4,500 people have died in extreme heat events since 1900.

- In Adelaide, the Australian Bureau of Meteorology defines a heatwave as three consecutive days with a daily maximum temperature of 40°C or more, or five consecutive days of 35°C or above. In Perth, the state government defines it as a mean temperature of 32°C or greater for one or more days.