Australia is installing home batteries at extraordinary speed.

Around 600,000 homes now have one, and more than 400,000 batteries were installed in the 12 months to June 2026. This growth has largely been driven by the federal Cheaper Home Batteries Program, which initially cut the upfront cost of eligible batteries by about 30%.

This is promising news. Batteries can help households use more of their own solar power and keep essential appliances running during a blackout. They also lower evening grid demand.

But there is a catch. A large battery can store more electricity, but can’t fix a house that wastes energy. That’s where our new research comes in.

Our new paper reviewed 97 studies on off-grid and self-sufficient housing. There was plenty of sophisticated research on solar panels, batteries and backup systems, but much less attention was paid to the design of the house itself.

A home’s orientation, insulation, windows, shading, ventilation and room layout all shape how much energy it consumes. Architects make decisions about these features early in the design process, often long before a battery installer becomes involved.

When these decisions are thoughtfully made, the house can remain comfortable while using less heating and cooling. This reduces the amount of electricity that must be supplied by solar panels and batteries.

A poorly insulated house, for example, will need heavy heating on a chilly winter’s evening. And if it has large, unshaded and west-facing windows, its rooms could overheat in summer.

After the sun goes down, your house may rely on electricity from a battery, the grid or another backup source such as a diesel or petrol generator. If your existing battery can’t meet your........

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