Auckland's largest real estate company has called on National to halt plans to scrap new Healthy Homes standards if elected.
Barfoot & Thompson said cold and damp rental homes had been linked to the gruelling battle with respiratory disease that affected 700,000 New Zealanders and cost billions of dollars each year.
It has co-signed a letter with the Asthma and Respiratory Foundation, doctors and other non-profit groups urging National leader Judith Collins to change course and back the new standards.
These require - from July 1, 2021 - that all rentals be fitted with insulation, heating and ventilation within 90 days of an existing tenant renewing their lease or a new tenant moving in.
Collins has called the standards "landlord bashing" and vowed to roll most back if elected.
The cost of refitting rental properties would drive rents up and hit renters in the hip pocket, she said.
But Barfoot & Thompson director Kiri Barfoot said the standards were not just good for tenants, but the whole country.
"Healthier homes mean children get a good night's sleep and then turn up to school and get an education - and people don't get so sick," she said.
The debate over Healthy Homes standards has turned into a major point of difference between the main political parties heading into next month's general election.
Labour - which introduced a raft of tenant-friendly laws over the past three years of the Coalition Government it led - has sought to portray itself as the party representing renters' rights.
National, on the other hand, claims it has gone into bat for landlords and the free market's power to deliver homes that tenants want.
National's housing spokeswoman Jacqui Dean said her party would not roll back current insulation standards.
But it would remove regulations that caused "an unnecessary burden" on landlords and drove up rents.
These included "the rules making it difficult to remove problematic tenants, the ability for tenants to modify rentals without permission, and regulations prescribing heating output on qualifying heaters that require advanced mathematics to interpret".
"National wants tenants to live in warm, dry homes but hitting landlords with too many regulations too quickly, without any incentives, only leaves fewer people wanting to be landlords," she said.
This would in turn mean there were fewer rentals left on the market for tenants to choose from, she said.
She claimed Labour's attack on landlords had already driven average rents up by $2600 a year.
However, the Barfoot & Thompson letter - co-signed by groups, such as the Hutt Valley District Health Board, Community Housing Aotearoa, NZ Green Building Council and university researchers - said cold and damp homes already cost the economy millions each year.
This was because New Zealanders were going to hospital 80,000 times each year with respiratory disease complaints, high electricity bills and lost productivity resulting from ill children and families struggling to fulfill their potential in life, the letter signatories said.
By scrapping Healthy Homes standards, National was shifting the bill from landlords onto taxpayers, the letter argued.
Labour's Associate Housing Minister Kris Faafoi said it was damning that doctors and other health and housing experts were writing to Collins asking her to reconsider.
"Most landlords are doing the right thing and supplying good homes," he said.
"Our new standards are about fixing the worst parts of the rental market and ensuring outlier landlords bring their properties up to a fair and reasonable standard."
"The fact that Judith Collins is acting in the interests of the worst offenders, rather than looking after people's health, is telling."
Barfoot conceded new rules around what type of heating was needed to meet the Healthy Homes standards were contentious.
"Sometimes people have to get a heat pump that they think is way above what is necessary to heat a lounge," she said.
"Those laws are a little contentious."
However, she said upgrading to Healthy Homes standards ultimately added value to rentals and helped protect them from mould damage.
It was really a "vocal minority" of landlords who opposed the changes, she said.
Many rental properties that Barfoot & Thompson managed had already been upgraded to meet the standards.
"The majority of owners are really positive and they want to upgrade their properties," Barfoot said.
The letter sent to National
Dear Ms Collins,
A recent report in the Herald claimed that "National under new leader Judith Collins confirmed to the Herald it would tear up new Healthy Homes standards".
We are writing today to ask you to reconsider this position, and instead back the standards that would ensure more New Zealanders live in warm, dry, healthier homes.
Doing so would be good news for the economy, for taxpayers, for New Zealand's international obligations, and would align with National Party values too.
Backing the healthy homes standards would provide more New Zealanders with healthier places to live, and therefore a better chance to realise their personal ambition and success, and provide for the needs of their household.
Scrapping, rather than backing, the healthy homes standards would mean, in future years, more children suffering from respiratory diseases, higher household bills for many New Zealanders, and higher emissions of climate change pollution.
Improving unhealthy New Zealand homes would save the economy millions every year. Scrapping the healthy homes standards would leave Kiwi taxpayers to otherwise pick up this multi-million dollar bill.
Cold and damp New Zealand houses have been linked to asthma, rheumatic fever and respiratory infections. Respiratory disease affects 700,000 Kiwis, is responsible for almost 80,000 hospital admissions, one-third of which are children, and costs New Zealand $6 billion a year, according to the Asthma and Respiratory Foundation NZ.
A recent report by the Green Building Council showed that going further than the healthy homes standards, and improving 120,000 New Zealand homes to the healthy standards that Kiwis deserve would deliver a net benefit of up to $3.1 billion, an economic stimulus, lower carbon emissions, improve health outcomes and create over 1000 new jobs. And research in the UK has found that home insulation programmes provide far better value for taxpayers than road building programmes.
We hope you will reconsider, and look forward to hearing from you.
Asthma and Respiratory Foundation NZ
Barfoot & Thompson
Community Housing Aotearoa
Hutt Valley District Health Board
New Zealand Green Building Council
Takiri Mai te Ata Whanau Ora Collective
Ngāti Tūwharetoa, Ngā Puhi, Ngāti Kahungunu ki Heretaunga
Lecturer, School of Architecture
Associate Professor Janet Stephenson
Director, Centre for Sustainability, University of Otago