Australian renters swelter in ‘worrying indoor temperatures’ of up to 40C in summer

Despite the cooler summer, renters are sweltering through temperatures as hot as 40C in their homes, new research has revealed, with advocates saying the cost-of-living crisis is forcing people to live in unhealthy conditions.

Tenant advocacy organisation Better Renting tracked the temperatures in 77 rentals across Australia between December 2022 and February this year and found that for nine hours a day they were above a safe level on average. Four jurisdictions recorded indoor temperatures above 40C.

The World Health Organization's recommended safe limit is no higher than 25C for more than nine hours a day.

Shasha, who did not want her last name to be used, rents a unit in the inner west of Sydney.

It is consistently hotter inside than out, with the top-floor apartment she shares with her partner hitting 46.8C on 26 December while the outdoor temperature at the time was 30C.

The bedroom where the 46.8C was recorded has large west-facing windows that get flooded with afternoon sunlight. They usually close the blinds but left them open to see how hot it would get. Shasha says it was like a greenhouse in their home.

"It's a single-glazed window and there's hardly any shade. Even though that was the highest, every day has been hot, stuffy and humid," Shasha said.

The pair have an air conditioner in the lounge room, but have to run fans in the bedrooms to sleep at night. Last quarter their energy bill was $300 - for winter it was $500.

"I've had to buy thermal blinds," Shasha said. "They come in handy for both summer and winter but it blocks out all the sun - so we turn it into a hole. It's the only condition where you can live comfortably."

The research showed that in New South Wales renters spent more than eight hours a day in temperatures above 25C on average. Western Australia was one of the hottest jurisdictions, with renters recording temperatures above 25C for about 15 hours a day and above 30C for more than two hours on average.

Renters in the Northern Territory endured unhealthy temperatures, spending most of their time in homes over 25C and five hours a day over 30C.

In Queensland, the maximum temperature was 42.1C, with renters spending three hours a day above 30C on average.

Despite lower temperatures in South Australia, renters spent more than nine hours a day above 25C on average and one recorded hitting 37.1C.

In Victoria and the ACT a cool summer meant temperatures stayed in a healthy range for the majority of the time and in Tasmania the renters spent at least 29% of their time in temperatures above 25C. One renter, who had a sunroom, recorded a temperature of above 50C.

The Better Renting executive director, Joel Dignam, said the maximum temperatures were not what renters were experiencing every day.

"But this is how bad it can get," Dignam said. "That any house can get that hot is pretty striking."

Poorly designed houses, with uninsulated ceilings and single-glazed windows, meant even in cooler temperatures renters were cooking over summer.

"When your rent and your energy costs are going up, one thing people cut back on is cooling," Dignam said.

"But when you're in a substandard home, this means suffering in excessive indoor heat. Even in this milder summer, we saw worrying indoor temperatures. As temperatures, energy costs and rents continue to go up, governments need to act to keep renters safe in their homes."

Melika Jordan rents from a community housing provider in Newcastle with her seven-year-old daughter. She faces major challenges with heat and mould that make it impossible to live in parts of her house for months at a time.

Recently the pair have been sleeping in a swag in the lounge room - where they have split air conditioning Jordan's parents bought for her.

"The max I ended up getting was 33.5C - that would have been the start of February," Jordan said.

"We got relatively lucky this summer - it's the coolest we've had. Before the air con, I was getting heatstroke every day. I was constantly sweating, dripping like I'd come out of a pool."

But the humidity has caused a big mould buildup in the house, which has affected Jordan's health, she said.

"I always heard stories of social housing being terrible, but I didn't get how terrible they are. Living in poor-quality housing, there are health effects."