Dunedin university students continue to live in flats that are colder inside than out, despite meeting Healthy Home Standards.

Advocates are calling for action over the frigid flats.

Second-year student Rosie moved into a Leith Street flat after a year in a student hall, where her room was warm and insulated.

The low standard of living came as a shock and she did not know any flats that could be considered warm.

Her flatmates wear jackets inside and she was sick for most of the first semester.

"We're all pretty restricted on our power use. We don't use our communal heat pump.

"We probably each individually have an oil heater in our rooms and we use that a couple of hours a day because rent is so expensive and power is so expensive in general, we're pretty reluctant to do that."

Her flat is about 100 years old.

"They couldn't access the walls to put insulation in and so there's only double glazing in one room, no insulation in the walls or under floor because they, you know, 'quote marks' couldn't access it, but we don't know how true that is," she said.

"It's honestly the same temperature as outside."

She did not think it was fair that students paid so much to live in these conditions.

On Castle Street, The Feisty Goat is up to healthy homes standards, kitted out with insulation, heating and ventilation.

But flatmate Dylan said the 145-year-old house was freezing despite the efforts of their landlord.

"We love the house, like it's real, real cool. Like we have a lot of fun, but it does get like freezing cold, especially at night," he said.

"We all got like girlfriends and we spend a lot of time spending the nights at their houses because it's actually too cold to sleep here, especially in the winter."

The heat pump did little to heat the home and remained turned off most of the time, he said.

Instead, most of the flat used dehumidifiers.

"I got this big jacket from my mum that she got given that she didn't need up in Auckland. So I took it down here and it's been probably the most worn item of clothing between the whole flat," he said.

He was hopeful the flat would be much warmer after draughty gaps in the property were filled using air sealing technology on Wednesday.

Students live in 'unsafe, unsatisfactory housing'

Otago University Students' Association president Daniel Leamy said it was almost impossible to find a decent quality flat.

"Perhaps in the 21st century, we maybe shouldn't be subjecting our young people to a, quote, rite of passage that essentially just means you live in unsafe, unsatisfactory housing," he said.

The Healthy Home Standards were good to have, but they were the bare minimum and they were not enforced, he said.

Students often knew their homes were not up to scratch, but many would not risk taking their landlord to the Tenancy Tribunal, Leamy said.

"The problem is the power dynamic between landlords and tenants is so, so unfair on young people who want to get a good reference so they can actually get more housing and another place to live, say next year if they move on," he said.

He was calling for more efforts to improve housing stock, and said students could access help from the association's support centre.

Shouldn't be accepted

Green Building Council residential impact manager Matthew Cutler said the old, cold student flats of Dunedin were well known.

"Some of the conditions here are just so bad for students and we've become as a culture, kind of accepting of that and I don't think that should be acceptable," Cutler said.

Draughty homes were a common problem as there was no requirement to measure air tightness of homes in New Zealand, unlike in many other countries, he said.

It should be easy to heat a home to a healthy standard, but it was often not the case, Cutler said.

"The healthy home standard is a really good start, but without a true warrant of fitness or an energy performance certificate, which is something that's very common in the residential sector across the world and certainly in the OECD, then it is really just the first step and there's a lot of room to improve that," he said.

Cutler said those improvements could include enforcing the standards as they relied on self-reporting, and also monitoring indoor air quality.