About 43 per cent of Canberra's rentals with a listed energy efficiency rating have shells that do practically nothing to protect residents from hot or cold weather, and it's putting their health at risk, experts say.
New analysis from Better Renting found that of nearly 4780 rental ads, about 2055 had an energy rating of zero. More than 6000 did not disclose a rating, meaning they could also be zero; compared to less than 5 per cent of nearly 7860 properties for sale that disclosed a rating.
"It's very unfair and the people in these properties are much more likely to be already at risk," executive director Joel Dignam said.
"[People say] if you want an energy efficient property, just pay more and rent [one].
"But the reality is that renters don't actually have that option."
The second most common rating for rental properties in the ACT is six. The National Construction Code requires new detached houses and row buildings to meet that standard, while new apartment buildings have to have a six-star average across all units.
Mr Dignam said Canberra's tight rental market forced people into inefficient homes, and they had to spend more on their energy bills as a result. Better Renting want disclosure of energy efficiency ratings to be made mandatory for rentals - like they are for properties for sale - as well as minimum efficiency standards.
"That could be compared to the rating scheme or just requiring specific measures be done by the landlord, such as having ceiling insulation, or making sure there is an efficient heater in the living area," he said.
Sale ads had an energy efficiency disclosure rate of 95 per cent.
The ACT government is developing a discussion paper as part of a review into the effectiveness of the energy efficiency ratings scheme.
Canberra-based cardiologist and physician Dr Arnagretta Hunter said it could draw on existing international research to determine the benefits of improved insulation, or conduct its own trials.
The territory was a "fantastic environment" to monitor how better living conditions impacted people's morbidity and mortality.
"Research has shown that a cold environment increases the number of days off school for children, influences days off work for adults, and influences hospital admissions," Dr Hunter said.
"It would be a great joint project for both housing and health in the ACT."
Cold homes could cause cardiovascular and respiratory issues in particular, Dr Hunter said.
While 30-year-old Dickson resident Cameron Van-Lane wasn't too concerned about his health, the poor insulation in his sharehouse caused him severe discomfort during winter.
He and his three housemates fork out $650 a week for their property but its windows have no double glazing and, like the doors, several gaps that let draughts in.
"My housemates and I live in down jackets during winter ... and on my bed I have four blankets to keep me warm during the night," he said.
"We do have a ducted heating system that's reasonably good when it's on ... however it is expensive to run and as soon as it goes off, the temperature starts to drop fairly quickly.
"When we don't have the heating on, often times during winter it's warmer outside by mid-morning than it is inside the house."
Mr Van-Lane believed Canberra's landlords had no incentive to "spend that extra money to ensure a comfortable and healthy living environment", especially given the difficulty of finding a property.
"I've had friends who have applied to dozens of properties and have had to queue up just to get an interview ... to move into sharehouses that were affordable," he said.
"I think having minimum standards would go a long way in ensuring a better quality of life for renters."