Urban Heat Islands
Cool Homes
Heatwaves in Australia kill more people than all other natural disasters combined.
Urban areas create heat islands which are hotter than surrounding areas, both day and night.
Water moderates climate, but the unshaded hard surfaces of urban areas (homes, footpaths and roads) contain very little water and protection from the sun, so are much hotter in summer and colder in winter. On a mild day in Katoomba we measured the temperature difference between pavers in full sun, and grass in the shade of a tree, and found it to be a surprising 30C.
There are a number of simple choices that can create cooler microclimates:
- choose materials made of lighter colours (particularly roads and roofs)
- choose surfaces that contain water (grass rather than pavers) and increase water bodies on site (eg. ponds)
- increase shading to block solar radiation
Cool Your Home Workshop
In our Cool Your Home workshop Dr Agnieszka Wujeska-Klause, Research Assistant to Associate Professor Sebastian Pfautsch from Western Sydney University, shared research on the Urban Heat Island effect in Western Sydney. She identified the most appropriate action to lower heat in summer and guided participants in how to use a thermal imaging camera to identify which surfaces retain the most heat. Thermal Imaging Cameras can be borrowed from Blue Mountains Libraries.
Living Underground
Hans and Tillie Coster built their home into a hillside in the Kanimbla Valley to protect it from climate change impacts. Building underground means that the walls and roof are in contact with the surrounding earth which is at an all year-round temperature of 14C regardless of freezing winters or sweltering heatwaves. They’ve also planted over 3000 trees.
Keeping it Cool with a Green Roof
A green roof, with moist soil and a vegetation layer, reduces energy use, boosts biodiversity and reduces bushfire risk. Read about a home in Linden where the owners have enjoyed the benefits of their green roof for over 30 years.
A green roof has the added benefit that it doesn’t take away from the footprint of the land and it provides plenty of greenery and foraging plants for insects and wildlife.