Ventilation rules to be revamped to ease plight of Auckland townhouse occupants

RNZ News

07-05-2025

A to hot townhouse in Auckland.
Photo:
Supplied
Building and Construction Minister Chris Penk says the government is planning to increase ventilation requirements in new homes, to address the problem of sweltering townhouses.
Auckland homeowners [https://www.rnz.co.nz/news/national/511585/the-big-bill-to-cool-new-auckland-townhouses
have complained of 30 degree Celsius temperatures overnight] and huge air-conditioning bills because of over-sunny and poorly ventilated buildings.
Penk said changes were needed to avoid people being "cooked alive in their own house".
Meanwhile, the Minister has pulled back from
wanting to repeal recent upgrades to energy efficiency requirements
.
The government is now proposing relaxing some aspects of the home efficiency standard, known as H1, as well as improving ventilation to keep homes cooler.
The minister told a housing conference he was disappointed that the issue of hot houses had been raised and debated through the media rather than being foreseen when upgraded energy efficiency standards were put in place.
Building and Construction Minister Chris Penk
Photo:
RNZ / Samuel Rillstone
Building and construction groups have said it's misguided to blame the problem of overly hot houses on increased levels of insulation that is being installed as a result of new energy efficiency standards.
They say insulation should help keep a house cool when the weather outside is hot, and the real issue is poor design, lack of shading and cross-ventilation.
Penk was asked at the Housing Summit in Auckland if he would be raising ventilation regulations and requirements for new builds.
He said the short answer was "yes".
Penk said the recent upgrades to energy efficiency standards had got "out of whack" with requirements to ventilate homes.
"It seems to me that the ventilation part of the Building Code needs an update and obviously the insulation or rather energy efficiency element has been addressed in the sense of the H1 rules," he said.
"It seems to me there's a bit of a mismatch there, certainly in terms of ventilation having got out of whack.
"I will say at the risk of being a bit provocative that I'm surprised and disappointed that the public discourse for this has gotten underway ... as far as I can tell with news items about how this is a problem and now reactively as a country how we've got to move to fix it," he said.
"It seems to me that with all the expertise that's available this is something that New Zealand Inc could have contemplated and considered and actively avoided," he said.
"We've got to see a regime where people aren't being cooked alive in their own house."
Photo:
123RF
The government appears to have pulled back from wanting to scrap upgraded energy efficiency standards, which critics blamed for hot homes and increased building costs.
RNZ revealed in July 2024 that Penk had asked building officials to begin work on rolling back changes to the H1 part of the Building Code.
The H1 upgrades to insulation and glazing requirements took effect in May 2023 and were the first significant improvements to insulation standards in New Zealand in more than a decade. They were designed to save a new home an estimated 40 percent on heating bills.
However, builders complained that the higher standards were increasing building costs by tens of thousands of dollars per house.
Officials at the Ministry for Business, Innovation and Employment (MBIE) told Penk the old standards were "significantly lower" than other countries with similar climates.
However, emails showed Penk asked them to start work on scrapping the upgrades and returning the standards to what they used to be.
At the time, he told MBIE he had decided that returning the Building Code to a "known prior state is the lightest possible touch in terms of making change….I am keen to move forward in any case".
But the government appears to have since backed down on making drastic H1 changes, in favour of smaller amendments.
Decisions
on H1 are made by MBIE, not the Minister
.
Many in the construction sector slammed Penk's plan to roll back the H1 changes, saying poor implementation was the reason for high costs and overhot houses.
MBIE appears to have agreed that drastic changes weren't required.
In February, MBIE consulted the industry on a range of smaller amendments aimed at lowering compliance costs and increasing flexibility while keeping energy efficiency gains.
This week, Penk told the Housing Summit the government was intending to relax H1 - but said any changes were ultimately MBIE's call to make.
He agreed with several industry commentators that one of the major problems was over-reliance on the so-called schedule method, where builders and designers work from a list of individual requirements for windows, insulation and other aspects to comply with the standards, rather than modelling the performance of the building as a whole. That can lead to
more high-cost elements
being included than are needed, as well as over-heating if the overall building's temperature performance isn't modelled.
"Anecdotally at least, but a lot of anecdote, a lot of people building a lot of houses are telling me that there is a huge amount of additional cost," Penk said.
"It seems to me - and I emphasise me because it is an MBIE decision - that the schedule method, the blunt instrument that's so prescriptive, has been the cause of a lot of a lot of designers and therefore builders adding a lot of cost unnecessarily, whereas if the calculation or, better still, modelling methods are used you can take account of regional variation.
"I think we will get to a more nuanced place," he said.
Penk received applause when he announced to the conference that New Zealand would be the 71st country to sign a global declaration on buildings and climate change.
The Declaration de Chaillot was signed by 70 other countries in Paris in March, 2024.
Countries agreed to work together on a "swift transition" to lower carbon emissions from buildings and make housing more resistant to climate change.
Among other things, signatories agreed to move towards carbon neutral buildings, to use regulatory tools to increase the share of resilient, near-zero emission, and affordable buildings; promote the adoption of green labels, standards, and certifications and lead by example by adopting ambitious policies regarding public procurement.
Andrew Eagles of the Green Building Council said joining the declaration was an "important step forward" and "very positive".
He said it would give the government an opportunity to meet regularly with other governments "to hear of the mahi happening around the world".
However, since the election the government has taken a number of steps in the opposite direction from the accord's roadmap.
It scrapped plans to bring in carbon measurements into the building code, will stop requiring Kainga Ora to build homes to top energy efficiency standards in order to save money, and proposed scrapping the use of Green Star ratings when the government is building or leasing larger buildings.