Here's why we need to think about turning old houses into energy-efficient homes
Monday, 11 September 2023
Changes to the Building Code mean a new era of energy efficient construction practices is coming, but it is not just new homes that will have to meet higher standards.
The drive to net-zero carbon by 2050 will impact on existing homes, and most will have to be bought up to the new standards, energy efficient builder Robert Whitehouse said.
Regulatory transition began in 2021 with changes to clause H1 of the Building Code, which regulates the energy efficiency of buildings, that MBIE said were the biggest in over a decade.
They focused on increasing roof and window insulation, with the aim of making homes warmer, drier and healthier, with less impact on the climate, and were now being implemented in new builds.
In December, the government proposed changes to the Building Act to reduce waste and lower emissions from the sector. They include mandatory energy performance rating requirements for buildings.
Housing Minister Megan Woods said buildings made up 9.4% of domestic emissions, and the changes were estimated to reduce emissions by 12.6 Mt CO2-e by 2050.
The changes set the foundation for the sector’s future climate change work outlined in the government’s Emissions Reduction Plan. That work was being led by MBIE's Building for Climate Change programme.
While the proposals only applied to new builds, the Building for Climate Change timeline showed emissions reduction policy measures for existing buildings would start to be developed.
Whitehouse, who is the director of Energy Efficient Homes, said if you looked at what was happening it was clear that from 2030 MBIE would be introducing more energy-efficient requirements for homes.
New builds would have to be energy-efficient by 2035, as it was a step-by-step process, but by 2050 there would be much higher requirements for existing homes too, he said.
“All existing housing stock will have to be brought up to those standards, and it will change the playing field. Most people don’t realise it, but most existing stock will be affected.
“People will say they can’t afford to upgrade, but when you look at the environmental side of things we can’t afford not to. It is a huge cost to our kids, and future generations, if we don’t do it.”
It was challenging to bring older homes up to the required energy-efficient standards, but it could be done, he said.
His company recently transformed a run-down, 1970s house in Christchurch into a cosy, energy-efficient home.
“We had previously built an energy-efficient home for the clients, and they didn’t want to give up the benefits of it when they bought a draughty, old house.
“An extension had been put on 20 years ago, and it wasn’t safe, so we had to strip the house right back to its bare structure, and rebuild it from there.
“We reinforced the foundations, and some walls, put in a new roof and windows, made it airtight, and installed a heat recovery system. It is now a warm, dry, healthy and energy-efficient home.”
The transformation did not come cheap, as the client did not skimp on luxury items, he said.
“They spent $1.175 million, which is a lot, but they bought the house for around $875,000. Overall, it cost $2.050m, but it was valued at $2.7m, so they are still on the right side of the market.”
Whitehouse said growing awareness of climate change was reflected in the increasing demand for energy-efficient new builds.
“They have major health and well-being benefits, and also result in significant energy-related cost savings over the long-term.
“Once more people realise this, it will have a snowball effect, and galvanise momentum to make existing homes more energy efficient too.”
Earlier this year an alliance of over 100 organisations, known as The Homes We Deserve, called for all political parties to commit to a “pollution busting home reno programme” for at least 200,000 homes within nine years.
Such a programme would slash carbon emissions and household bills, improve the health of thousands, create tens of thousands of jobs, and bring billions of dollars of economic benefits, it said.
Last week, Woods announced that if re-elected Labour would introduce a rebate pilot for owners who undertook a deep retrofit, full insulation upgrade, or the electrification of their existing home.
Depending on the level of work done, rebates ranging from $3000 up to $18,000 would be available through the scheme.
Green Building Council chief executive Andrew Eagles said Labour’s pilot should be the precursor to a much larger, much needed, pollution busting home reno programme.
He welcomed Labour’s announcement, but said it was high time all political parties made similar promises to ramp up improving homes significantly.
In August, the Green Party announced a policy that would cover up to 25% of the cost of zero-carbon home upgrades such as rooftop solar, heat pumps, and better insulation like double-glazed windows.