Photo: 123RF
Too many new homes are overheating in the increasingly hot summers and the government is being urged to follow other countries' leads and do something about it.
There is currently nothing in the Building Act to prevent new builds - particularly terraced homes and apartments - from experiencing "unacceptably high indoor temperatures", as is being "widely reported by homeowners, designers, and the construction sector", an open letter to Building and Construction Minister Chris Penk released on Monday morning read.
The letter was signed by Phil Wilson, chief executive of Auckland Council, and his counterpart at the New Zealand Green Building Council, Andrew Eagles, and backed by a range of groups covering architects and the construction industry.
"As we approach the warmer months, there is increasing evidence that many recently built homes are experiencing unacceptably high indoor temperatures during summer," the letter said.
"The Building Act's primary purpose is to ensure people can use buildings safely and without endangering their health. Current regulatory settings do not adequately address overheating, particularly in modern higher-density housing typologies."
Penk himself acknowledged the issue at a housing summit in May, saying changes were needed to avoid people being "cooked alive in their own house".
At the time, the minister said he was disappointed the issue had been raised and debated through the media rather than being foreseen when upgraded energy efficiency standards - such as better insulation - were put in place.
In response to the letter, Penk on Monday said ventilation had been "neglected" while the focus went on insulation
"It is surprising and disappointing in equal measure that the Building Code that I inherited was so deficient in matters of ventilation," he said, saying both were "hugely important".
"I'm determined that we rectify this situation. An upcoming review of the Building Code will include a strong focus on preventing the over-heating of multi-storey dwellings such as townhouses."
'A sauna without the fun'
Monday's letter said with the number of days with temperatures above 25C projected to more than triple by 2050, changes were needed to prevent cost blowouts for occupants resorting to air conditioning.
"From an economic and environmental perspective, reliance on air conditioning to manage these conditions places additional cost burdens on households and adds to peak electricity demand, creating unnecessary strain on the national energy system and sadly undoing great strides towards being energy efficient in our houses."
Current designs prioritised access to sunlight, the letter said, but not shade, and the "shift toward higher-density housing has intensified the issue, as terraced and apartment dwellings have fewer external walls and openings, reducing opportunities for natural cross ventilation".
It proposed similar measures to those used in Australia, where architects were required to model overheating at the design phase, and show a building would stay within reasonable heat limits.
In May, Penk said the government would be raising ventilation regulations and requirements for new builds.
An Auckland Council study conducted last year found some newly built terraces and duplexes in the city were getting too hot.
Council urban design manager Lisa Dunshea said a combination of poor window placement, minimal shade, and a lack of natural ventilation was behind the problem.
Wilson said there were already tools available to help designers build cooler homes, but they were optional.
"It would be good to see this mandated in the Building Code for terraced housing and apartments."
Speaking to Morning Report, Eagles said it was a "real sad situation" at a time where people should be happy about moving into a beautiful new home.
"All too often we're finding that people are getting quite upset about the discomfort they are feeling, they're getting really high temperatures at night, we've got people saying 'my home is like an oven' or 'it's like a sauna without the fun'. That's causing sleep issues and real concerns and often it's a really difficult issue to remedy."
Eagles said his organisation and Auckland Council had expressed concerns for some time now and was calling for action.
It was a simple fix - as shown overseas - and just required designers to check if a home was at risk of overheating at the design stage.
Designers could then get the information and consider how to rectify the issue - such as using ventilation, shading and orientation.
Eagles said he sees "hundreds of homes" getting it right and delivering comfortable homes for Kiwi families - but with more about 50 percent of homes terrace or apartments - and at greater risk of overheating - the change was needed in the code.
He said it did not require legislative change and would only take "three lines" in the code.
It would not make building more expensive - if any, there would be less cost involved, he said.
He called Penk's focus on ventilation a "distraction".
"Auckland Council, the construction, research and design community are calling for a check at the design stage to ensure homes don't overheat. This is done in Australia, the UK and other jurisdictions. It was uncontroversial when bought in.
"This step will address issues of excessive solar gain that ventilation does not. It works because it means designers get the glazing, shading and orientation right to ensure families do not overheat."
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