Homestar: an independent rating tool for New Zealand homes

The Zero Energy House in Pt Chevalier achieved an 8 Homestar rating. Photo / Supplied

Homestar can help you ensure your house is both efficient and sustainable.

Not all New Zealand houses are created equal when it comes to energy efficiency, health and comfort - just ask anyone who's lived through a winter in an uninsulated villa. But unless you have prior knowledge of building or design, it can be difficult to know which homes tick the right boxes. That's where Homestar comes in.

Homestar is a comprehensive, independent rating system that assesses and rates how well our homes are designed and constructed to perform to health, warmth and sustainability standards.

The tool rates new and existing homes on a scale from 1 (minimum) to 10 stars (world best-practice). Several categories are assessed: energy, health and comfort; water; waste; home management; materials; site; and an optional innovation category.

NZGBC CEO Alex Cutler says a Homestar rating is valuable for people who want to improve their homes, and those looking to sell.

"It provides independent assurance to buyers about your home's warmth and efficiency, and international studies suggest highly rated homes attract a resale premium," explains Cutler. "Going through the Homestar process prompts you to assess your home and sustainability behaviours, and make positive changes."

Homestar's free, online self-assessment tool is a great starting point. It takes around 20 minutes to answer, and you get a provisional rating and a checklist of practical, unbiased advice for renters and homeowners.

Potential savings vary from region to region but, broadly speaking, in Auckland a 6 Homestar home will be 38% more energy efficient than a 3 Homestar home.
Much of New Zealand's existing housing stock is substandard and poorly insulated. Most new New Zealand homes, built to Building Code standard, only reach a 3-4 Homestar rating. "The Building Code sets the bare minimum," said Building and Housing Minister Nick Smith at the 2014 Sustainable Housing Summit.

Cutler says it's worth aiming higher. "There's a misconception that building this way adds significantly to a project's cost. In fact, achieving a 6 Homestar rating adds just 1.5% to the purchase price - or nothing at all if the house is slightly smaller than today's larger homes," she says.

Small ways to save money

An average-priced LED could save you $290 over the life of the bulb (source: EECA Energywise).

Replacing a 12-litre-per-minute showerhead with one that flows at eight litres can cut your hot water bill by $153 a year, while still offering a comfortable, effective shower (source: Consumer NZ).

A dripping tap can waste up to 33 litres each day (source: Watercare).

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