How can I keep cooler at home this summer? We asked an urban heat expert
Dr Negin Nazarian, a researcher in urban heat from UNSW Sydney, shares her expertise to help us keep cool at home.
Dr Negin Nazarian, a researcher in urban heat from UNSW Sydney, shares her expertise to help us keep cool at home.
Samantha Dunn
UNSW Arts Design & Architecture News & Content Coordinator
0414 924 364
samantha.dunn@unsw.edu.au
Dr Negin Nazarian, from the School of Built Environment at UNSW, is an expert in urban heat. We asked her how the science behind urban heat research could help us keep our homes (and therefore ourselves) cooler over summer.
“On a hot sunny day, the winning strategy is to stop the heat from getting into your space,” says Dr Nazarian. “Cooling is harder once your home has heated up. In the urban environment, any way that radiant heat from the sun can be prevented from being absorbed by surfaces or heating a space is key to keeping cool in the face of high temperatures. In urban environments this looks like designing buildings using effective insulating materials, orienting larger windows to be north rather than west facing, using awnings or shades that can be adjusted, and ensuring windows are double glazed, tinted or shaded to prevent radiant heat getting into the space.” The Australian Government’s Guide to Environmentally Sustainable Homes says up to 87 per cent of a home’s heat is gained through windows, so improving the thermal performance of windows is a great way to keep cooler.
“When looking at heat mitigation in urban settings one of the factors that can help lower temperatures and keep people cooler is planning settings that ensure buildings are oriented to take advantage of breezes that come from the ocean, or ponds, dams and lakes. Another is to ensure there is space between buildings to allow for ventilation which moves heat out of the urban environment,” says Dr Nazarian. “Now, while you can’t change the location of your home to catch the ocean breeze, you can certainly try to create avenues for air to pass through. This means when you open a window, open a door and a window on the other side of your home too, to create cross-ventilation and allow air to move through your home.”
Take advantage of any cool breezes during the early mornings, evenings and overnight. Open windows on opposite sides of your home to create cross-ventilation. This allows fresh air to flow through and hot air to escape. And when the wind is hot, close those windows to keep cooler air trapped in the house if possible. You can also check the weather stripping on doors and windows to keep the cool air in.
Read more: 5 ways to cool cities as temperatures soar
“Air-conditioning is a very popular way to cool homes, but it also has some downsides in terms of the energy used to run it and the heat it creates,” says Dr Nazarian. “Indoor fans are relatively energy-efficient and make a room feel cooler by circulating air – much like ventilation does. In fact, recent research shows that fans can be effective at keeping people cool even at temperatures as high as 40 degrees. Interestingly, some cities use misting technology to cool people, and there are also misting fans and evaporative coolers that people could use in their homes,” she says. A note of warning though: “Misting options only work in hot and dry conditions, and if you use them in humid areas the water droplets can actually have a negative impact on heat stress as they reduce the body’s ability to cool itself through sweating.”
Don’t go straight to the big guns of air-conditioning when you want to keep cool. Use fans to circulate air in rooms in your home. Portable fans, such as floor or table fans, can be really effective and you can move them around the house to provide direct cooling where you need it most.
“Increasing both green and blue infrastructure is an important part of creating cities that can mitigate the effects of increasing temperatures in the face of global climate change,” says Dr Nazarian. “In cities this can look like establishing parks and planting lots of trees and adding lakes or dams to the landscape too. While trees and parks can’t reduce rising temperatures, they can make them easier for people to endure, as they provide shade and respite from heat. And the same ideas can be adapted on a smaller scale in your back garden or streetscape.”
If you live in a house, plant trees and shrubs strategically around your home, especially on the north and west sides. The natural shade they will create can help reduce indoor temperatures.
“Though you might need to wait a few years to feel the benefit, they are an important investment in your future,” says Dr Nazarian. “Deciduous trees are excellent choices because they provide shade in summer and allow sunlight through in winter when their leaves fall. And if you don’t have access to a back garden, you could be part of creating verge gardens or urban forests in your neighbourhood to increase the green space you have access to.
“As for blue infrastructure, making the most of pools, lakes, streams, the ocean and even cool baths, are great ways to cool down when the weather is hot.”
Read more: Tiny pocket parks make a big impact on urban living
“Using light colours in the built environment is one of the tactics used to reduce heat in cities. Some examples include light coloured roofing and paints engineered to reflect light away from buildings so less is absorbed as heat,” says Dr Nazarian.
“The same idea can be applied to what you wear to keep cool. Lighter colours reflect heat, and looser clothing allows air to circulate around your body to move heat away.
“Researchers are also always seeking ways to reduce the heat created by human activity. So, the same can apply at home. Think about what creates heat in your home and do less of it. The summer barbecue is your friend, as cooking outside means you’re not heating your home at the same time. Though if you’re in the middle of a heatwave, avoid being outside if you can.”
And make sure you stay hydrated, says Dr Nazarian. “And, my last tip, cold water is more effective at keeping you cool than water at room temperature!”