The programme began under a National-led government in 2013 in Auckland and has now expanded to 11 district health boards (DHBs) in the North Island.
It initially focused on areas with high rates of rheumatic fever but this has been expanded to also cover pregnant people, low-income households with sick young children and other social factors.
The Government last year announced extra funding to expand the programme across the rest of the country from July.
Under the programme, the Government funds assessments of interventions needed, which can then range from removing mould and improving insulation and ventilation to replacing damp and mouldy bedding and furniture.
Most of the interventions are funded by philanthropic organisations.
The programme is separate to Health Homes Standards, which came into force on July 1, 2019.
Ardern said in some cases, the differences made were simply giving people the ability to heat their home.
Asked whether she was confident state homes were compliant with the standards, the PM said not yet but work was continuing in the area.
State landlord Kāinga Ora has until July next year to ensure its houses are up to standard.
She said the Government inherited state homes that weren't compliant.
According to the 2018 Census, people living in Kāinga Ora properties were more than twice as likely to report their homes being "always damp" as those living in private rentals, and more than 15 times compared with homes owned or held in a family trust by the household.
Kāinga Ora houses were also nearly twice as likely to have tenants to report a section of mould over a piece of A4 paper in size "always", compared with the private rental market, and more than eight times more likely compared with homes owned or held in a family trust by the household.
Report co-author University of Otago associate professor Nevil Pierse said the initiatives were making a "huge difference" to the families involved.
"This shows it really works. It shows how much housing matters to health, and how easily reversible poor health outcomes are."
Coinciding with reduced levels of illness, school attendance of children involved increased by three per cent and employment by four per cent.
Pierse, who is deputy director of He Kainga Oranga/Housing and Health Research Programme, said while successful the scheme was still relatively small-scale and given the scale of New Zealand's poor housing issues should be expanded further, not just to low-income households.
A report by the Asthma Foundation in 2021 found the rate of respiratory hospitalisations was 1105.9 per 100,000 people in 2019, and had increased at a rate of 17.2 hospitalisations per year since 2000.
Māori and Pasifika were more than twice as likely to suffer from these illnesses than average (Māori and Pasifika make up 94 per cent of those involved in Health Homes Initiatives).
"We have one of highest rates of respiratory illness in the world, and for rich countries some of most inefficient housing, which I continue to be shocked at," said Pierse.
"We have a long history of building badly [in New Zealand] to low standards and not maintaining houses.
"We now have a lot of good ideas and tools in place but it is a big challenge to meet."
Associate Minister of Health Ayesha Verrall said everyone deserved a "warm, dry, healthy home".
"Poor housing stock can make people sick and by improving housing conditions, people are healthier and more likely to stay in school or in work, while also relieving pressure on the health system.
"These results support our decision to expand the programme to nationwide coverage. We inherited a programme that was underfunded and narrowly targeted. We've invested $30 million in the initiative and in Budget 22 funded its extension to the whole country.
"We anticipate that this expansion can extend the benefits of the programme to a large number of people across the whole country.
"This is an example of our wellbeing investment working. Programmes like this are improving the health and wellbeing of New Zealanders and are a key component of our plan to make New Zealand the best place in the world to be a child," Verrall said.
Initially, the programme targeted low-income families with children at risk of rheumatic fever, but was expanded to focus on families with children aged up to 5 and pregnant women, and recently rolled out to the rest of the country.
Associate Minister of Health Aupito William Sio said the Healthy Homes Initiative had made a huge impact on the health and wellbeing of over 31,000 tamariki/hapū māmā and over 111,000 members of their whānau/aiga.
"It's significant that 94 per cent of referrals identify as Māori or Pacific. Many in our communities live in multi-generational households and have multiple health conditions," Sio said.
The report said more than $55.6 million had been spent over eight years from December 2013 to December 2021, with the main costs staffing.
Pregnant woman's ICU death
When asked about the Palmerston North hospital death - where a pregnant woman with sepsis died after admission to ICU was delayed for several hours - Verrall said it was a tragic incident and said we will have to see the result of the Coroner's investigation.
About the culture at the hospital, Verrall said issues of culture and how the escalation of how people who have sepsis are dealt with will be covered in reports.
On the hospital death, Ardern said the first thing that stood out to her was the request for privacy from the family but said it was a "devastating story".
Ardern was also asked about National branding various Government initiatives as taxes.
She said it was not a fair representation and there was a lesson to be learned from overseas institutions implementing wide-ranging tax cuts and the impact on markets, pension funds, inflation etc.
Ardern didn't believe it was unfair to compare National's plan to introduce tax cuts with those brought in in the UK.
On visitor visas, Ardern said the group of visa applicants don't make up the majority of people coming into the country for tourism. The majority don't require a visa.
Those who do, are from specific countries and they make up about 12.5 per cent of tourists. China has been removed from this group as they are tending not to travel at the moment, Ardern said.
From August 1, median visa processing time was 14 days. Ardern was happy to see that time quickening.
On issues getting chefs into the country, Ardern said it had been identified as an issue and said the Minister of Immigration, Michael Wood, would elaborate on a temporary solution in the coming days.
During the press conference, Ardern affirmed her support for Wellington mayoral candidate Paul Eagle, following her Instagram post endorsing him. She confirmed she would be making a similar post for Labour-backed Auckland candidate Efeso Collins tomorrow.
Ardern wouldn't speculate on what the lowest turnout threshold would be for local elections to be considered invalid.
On her meeting with representatives from the Solomon Islands, Ardern said she wouldn't be interfering regarding relationships between other countries, when asked about the Solomons' lack of engagement with the United States.
On Iran, Ardern said she had been "deeply concerned" by the loss of life and the human rights issues for women and girls. New Zealand's concerns had been raised by MFAT, Ardern said.
Asked why the Indian foreign minister is making a visit at this time, Ardern said she could not speak on their behalf. Asked how significant it is to have a visit for the first time in 20 years, Ardern said she hoped to strengthen the trading relationship between the countries.
The final of the three cost of living payments has been paid out today.
The payments were intended to help middle-income households with the rising cost of living, but became a political football after a messy rollout from IRD.
On RNZ, Ardern played down the suggestion that the government would make available additional fiscal support for households beyond the current fuel excise and road user charge cut which expires at the end of January.
She said additional support could make inflation worse.
"Certainly what you do in this area can have an inflationary impact," Ardern said, criticising National's tax cut package for likely adding to inflation.
