Our hot, humid summers are a mixed blessing for Australians. On the one hand, they give us a good excuse to spend a lot of time outdoors. On the other hand, they can make staying indoors almost intolerable. One solution is air conditioning, but that is an expensive, arguably unhealthy and environmentally unfriendly way to keep cool. A better way is a sensible building plan that maximises air flow throughout the house and minimises the tendency for the home to become a heat trap. These are some ideas to think about when building
in a hot climate.
In Coober Peedy, where the temperatures soar, settlers found a novel way to keep cool: they built their homes and businesses underground. Thinking along the same lines, the brick and double brick home became an Australian icon. Unfortunately, brick is one of the worst materials you can choose if you're building in a hot climate because it absorbs and retains heat. Timber or modern fibro are better choices in a hot climate because they cool quickly when the temperature falls at night.
When building in a hot climate, ventilation is of paramount importance. Perspiration is a natural body coolant, but it only cools the body if it is fanned by a breeze. Producing cross-ventilation in the home is the key to getting a cooling breeze to pass through:
- Louvres and/or shutters should be positioned so that prevailing winds can enter on one side of the house and exit on the opposite side.
- To allow trapped hot air to exit from the ceiling cavity, install rotary vents on the roof.
- Wind traps on the roof facing prevailing winds catch breezes and direct them into the home.
- A ceiling fan helps circulate air.
If your house is elevated, it will stand a better chance of catching breezes which may pass over a low-set house. The danger here, though, is if you live in a cyclone-prone area. If this is the case, expect greater construction costs and choose a building consultant
with extensive experience in cyclone-proofing.
Some other things to consider when building in a hot climate include:
- An open plan is better than a series of smaller rooms.
- Position the bedrooms so they can can be ventilated from the front and back of the rooms.
- Heat-reflective foil insulation is better than thick insulation in a hot climate.
- Provide shade from the direct rays of the sun on outside walls.
- Metal roofing materials cool quickly at night. Choose roofing that has a reflective coating underneath to minimise heat transference during the day.
Just as you want to allow breezes to pass through the home as unobstructed as possible, you want to allow them to reach the house from the outdoors:
- Low fences allow breezes in while high fences block breezes.
- Low shade trees with wide canopies block breezes. Choose tall palms instead.
- If you live in a suburban area, choose a wide block of land and allow as much space between houses as possible.
Most of these are low cost yet highly efficient ways of building in a hot climate. The more of them you can implement, the more comfortable your house will be and the less you will have to rely on air conditioning.