How to keep your house cool in summer

Jan 29, 2019

keep house cool in summer

Living in Canberra, our long and frosty winters often make us forget how overwhelming the heat can get during summer. But once January and February roll around, we find ourselves struggling to keep cool, with temperatures frequently soaring to 38 degrees and higher.

For homes that are less equipped to deal with rising temperatures, the heat can quickly become unbearable. And for the very young or very old, these extremities can be especially worrying.

As a gauge, the ideal temperature inside your home in summer should be around 25-27 degrees Celsius. Because we’re located further inland, Canberra rarely has to deal with high humidity. So with appropriate clothing and sufficient air flow (i.e.: fans), this is relatively easy to achieve.

However, the laws of physics mean that the air inside the house will always try to match the temperature outside.

When we are fortunate to have warm days and cool nights, this gives us the perfect opportunity to also cool the air inside. I.e.: if you can do it securely, keep windows open (particularly on the eastern side of the house which hasn’t been warmed by the afternoon sun) so the cool night air can replace the warm air inside and also cool solid surfaces, such as concrete slabs.

But what do you do during a heat wave, when the heat gets progressively worse, with no cool night air to provide relief?

Throw energy at it

This is the most obvious, yet least cost effective and environmentally friendly way to alter the temperature inside your home. But when enduring a heat wave, reverse cycle air conditioning (electric or gas), or split systems can provide great relief for the whole family.

Of course, relying on electrical systems does leave you at risk of hardware faults, and even rolling blackouts due to excessive demand on the grid.

Because of our low humidity, evaporative coolers work really well in the ACT. They use less power than reverse cycle air conditioners, and push hot air out rather than blowing cold air. You can also leave windows and doors open to keep the fresh air circulating.

Design your home like an esky

With hot air trying to seep into your home through every orifice, there are two strategies you can use to slow the process: insulation and airtightness.

Quality insulation slows the heat down from entering the house so it takes longer to heat up inside. If you don’t have proper insulation in your house, keep this in mind for your next build or renovation. Windows are way less effective than insulated walls and ceilings at keeping heat out – upgrades to windows (e.g. double glazing) is a very effective measure.

Airtightness is also an effective way to keep the heat out. To do this, you need to examine any gaps in brick or around windows and doors and seal them up. Keep external doors closed, and if you are planning any upgrades to your home, consider double or triple glazed windows and doors (especially on north-facing sides). Also make sure you can close air conditioning vents when they aren’t in use.

If you’re seeking non-energy-consumption methods for cooling your house, try taking a leaf from our grandparents’ era. Their strategy was to close all the doors and windows, keep heavy block-out curtains drawn, and turn on ceiling fans. The heavy/double brick nature of their houses also meant that heat took longer to be absorbed into the house.

Reduce the heat load

A few additional steps you can take to minimise the heat in and around your home include:

  • Shading or fixing external blinds to windows that receive direct sunlight
  • Planting trees near sun-facing windows
  • Shading west and east-facing walls that receive low angle sun
  • Minimising concrete or paving near windows that absorb and store heat

Lastly, keep in mind that newer suburbs are often hotter than established ones. This is because there tend to be smaller and less established trees, and a higher density of solid surfaces. This is important to consider if you are planning to build a new home.

Building a new home does give you a lot more flexibility when it comes to creating energy efficiency. We may have artificial means to cool our houses, but we also have proven design techniques and technologies to achieve this now too.

To learn more about these techniques and technologies, and how to maximise energy efficiency in your new home, call Rosin Bros on 6247 4799 or email

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