It's been seven months since laws came in requiring landlords to insulate their rentals, but some tenants say it's far too easy for landlords to avoid the rules, and the Government admits it has no idea how many Kiwi rentals are compliant.
In July last year, it became law for landlords to have ceiling and underfloor insulation in their rentals.
Landlords can claim their property is exempt if it's not "reasonably practicable" to install insulation, but they aren't required to prove it.
By law, landlords must provide a statement to tenants detailing whether the property meets insulation standards, but the ministry in charge of rentals - the Ministry of Business, Innovation and Employment - doesn't know how many properties are exempt, as it only checks up on a small fraction of the country's rental properties.
Advocacy group Renters United says that's not good enough.
Spokesperson Robert Whitaker says when a Government introduces standards, it should be responsible for enforcing them.
"Landlords have to make a statement, but landlords aren't required to provide evidence that they've actually done it," he told 1 NEWS.
"If the tenant doesn't think their landlord's been honest in their statement then it's entirely up to the tenant to investigate and take a case to the tribunal.
"We think that's pretty unfair, why should tenants be responsible for enforcing a law the Government has introduced?"
That's the exact situation a Wellington renter found himself in late last year.
Francis, whose name has been changed by request, decided to check on the insulation in his flat after two years of living in cold and damp conditions.
"When I found out about the regulations, I got up into the attic and as I expected there was no insulation, it was pretty much just mouldy wood," he told 1 NEWS.
Francis says he asked his landlords if they were intending on installing insulation the following year.
"They ignored me, I sent them a text and they didn't respond. I decided they weren't gonna do anything about it so made an application with Tenancy Tribunal, the landlords got particularly aggressive about wanting to get us out of the flat."
Francis won his Tenancy Tribunal case, but won just $1500 from his landlord, $400 more than his weekly rent.
"It's absolutely not worth it the amount of hassles it's caused me having to move out," he says.
"The money I got from the landlords, I had to put back into paying rent anyway."
Steve Watson from MBIE's Housing and Tenancy Services unit says the ministry's tenancy compliance and investigation team has 39 staff spread across the country.
They are funded to do 2000 investigations a year, but they only focus on where harm is most likely.
Mr Watson says there are no plans to introduce insulation compliance checks for every New Zealand rental.
"Most tenants will communicate well with their landlords, in most cases it's a question of asking your landlord to provide evidence that's correct and they will do so," he says.
"Most are good people who do want to do the right thing, there are a small number who don't."
No property investor groups 1 NEWS approached would appear on camera, but the president of Capital Property Investors Association Adam Cockburn says it's reasonable not to introduce checks for every rental and that doing so would ultimately mean higher rents for tenants.
"Given rents are already high, and given the insulation requirements appear to be being complied with in the vast majority of cases, we do not believe the benefit to tenants of increased compliance oversight would be worth the additional cost which they would ultimately bear."
Renters United disputed the need to pass costs onto tenants.
"Rents are rising massively at the moment, that's not because landlords' costs are going up, it's because there's a constraint of supply," Mr Whitaker says.
"The reality is, rents are not connected to landlords' costs, rents are based on what landlords can get out of tenants for their houses."