A new energy-efficiency rating for houses has been launched on Thursday, but the group behind it doubts any will ever achieve the highest score.
The Government-endorsed Homestar programme was developed after a report stating more than half of the houses in New Zealand are too cold and inefficient.
The voluntary ranking system ranges from zero to 10 for the most efficient.
To achieve a 10-star rating, a house needs to be built with environmentally friendly materials, have good insulation and glazing, and be able to produce its own energy.
Homestar general manager Leanne Beard says the average New Zealand house hovers between a two or three-star ranking, but with basic insulation can instantly be upgraded to a four or five.
The aim of the ranking system is to encourage owners to make their homes healthier and to act as a guide for buyers.
Homeowners can assess their own properties for free online at Homestar's website, but will need to get official verification to market their properties with the ranking.