Experiment finds 'passive' house standard better than building to NZ code

The results of a nine day IceBox Challenge in Christchurch were revealed today.

Two mock homes, one built to New Zealand code, and the other to an energy efficient "passive" house standard, were tested to see which is better at keeping a comfortable temperature.

Five hundred kilogram blocks of ice were placed inside the houses, and as experts predicted, it was "the passive box" that performed best.

"The passive box retained 70 per cent of the weight of its ice, where the code box lost over half," said Theeca Group's Glenn Murdoch.

"It simply comes down to having a well performing building envelope, so there's a little more insulation but not dramatically more.

"There's an airtight building structure, so that looks after the insulation and makes sure it keeps working and the window is of a higher specification."

Organisers of the IceBox Challenge hope to see it carried out in other parts of the country.