Experts say air conditioners will be a huge stress on power grids this summer, with many more people working from home.

Roy Morgan researchers say more than 4.3 million Australians are working from home, and the increased use of air-conditioning in homes may lead to more blackouts and higher electricity bills.

“Air-conditioning is what drives our maximum demand in Australia,” says Peter Dobney, former chairman of the Energy Users Association of Australia.

“We can expect higher prices, in fact, I think that's a certainty.”

Some major companies will have just 50 per cent of staff in the office this summer.

“It's very clear there is a risk here, with the air-conditioning running in the home and in the building at the same time,” says energy efficiency expert Dr Paul Bannister.

“And cooling a house, it's not as well insulated as a building, and the home may be less energy efficient.”