Green building advocates say winter power cuts wouldn't be an issue if New Zealand's housing building standards were not decades behind most other countries in the OECD.

On Friday national grid operator Transpower warned demand could exceed supply during the morning peak, amid freezing temperatures.

The Green Building Council chief executive Andrew Eagles says the threat of power cuts was the result of decades of neglect.

"For years we've been calling for [governments] to deal with the terrible state of New Zealand homes. Millions of New Zealanders live in poorly insulated and draughty housing - there's no wonder when the weather gets cold, they need to blast the heater."

"It's like watering a garden with a leaky hose filled with holes. We can turn on more water, but what's the point if we don't stop the leaks?"

Andrew says that after what happened on Friday morning, there would be "a lot of talk about new electricity generation. It's vital that actually we look at one of the major causes of [Friday] - cold, inefficient housing".

He says the government should commit to a major retrofit programme similar to those being done in Ireland, Australia and the US.

"Research from Otago University shows actually if we built to best-practice standards, as the majority of the OECD already are, we could reduce the winter peak by 75 percent. That's huge, and not only takes pressure off the grid, but would be a massive win for New Zealander's health and cost of living."

The 2021 research, by associate professor Michael Jack, found the reduction from building better homes was so dramatic, that despite predicted growth in floor area and achieving healthy temperatures, the winter peak in 2050 would be less than the current peak.

Ahead of last year's election the Green Building Council was one of 170 organisations from across New Zealand who called for politicians to commit to a major retrofit programme to tackle the state of New Zealand homes, he said.

"This is what most of the OECD is doing, investing in healthier warmer homes, making their grid vastly more efficient."

Eagles said the Institute for Energy Economics and Financial Analyisis in Australia has just published similar research to that of Otago University's.

"Rather than mining for more gas, a more financially prudent approach is to lead with demand reduction."

RNZ