1. What is Homestar? 

Homestar is an independent, evidence-based rating system developed by the New Zealand Green Building Council (NZGBC), and used in New Zealand to measure and improve the performance of residential buildings. Homes are rated from 6 to 10 Homestar stars — the higher the star rating, the better the performance.
Rather than focusing only on how a home looks, Homestar looks at what really matters — how healthy, warm, dry and energy-efficient it is. It provides a certification standard that goes beyond the minimum requirements of the current Building Code and Healthy Homes regulations, and supports better decision-making at the design and build stages of both new and existing homes.

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By assessing essential performance elements together — including insulation, window performance, ventilation, heating, solar gain, and energy and water use — Homestar reveals how homes perform in real life. As a result, it:

• Delivers warmer and more comfortable living spaces.

• Creates healthier indoor environments by reducing dampness and condensation, helping to prevent moisture-related issues inside the home.

• Reduces energy consumption and lowers household energy bills.

• Guides targeted and sensible upgrades for existing homes.

• Improves a home’s long-term performance and overall value.

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2. Can an existing home be upgraded to achieve a Homestar rating?

Yes. Many existing homes can significantly improve their Homestar performance through better insulation, glazing, ventilation, heating and moisture control.
However, each home is different — a site survey and Homestar model is required to determine what is realistically achievable.

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3. Does a Homestar rating increase property value in New Zealand?

In most cases, yes. Carrying out these upgrades can increase the value of your home immediately, at varying rates depending on its location.
Homestar-certified homes tend to offer:

• Lower energy bills

• Improved indoor air quality

• Greater comfort

• Stronger market appeal.

These factors often contribute positively to resale and rental value.

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4. What is the difference between Homestar Design and Homestar Assessor service?

Homestar Design and Homestar Assessor refer to two different stages of the certification process and two distinct professional roles.

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Homestar Design Service is the "planning" phase. It creates a roadmap to ensure the house will perform well. It is a performance model carried out by an accredited Homestar Designer using ECCHO calculation tools, to show what upgrades (to existing homes) or design specifications (for new builds) are needed to reach a targeted star rating.

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Homestar Assessor Service is the "verification" phase. It proves the house was built correctly and unlocks the official certificate. It is a managed process led by an accredited Homestar Assessor, including site visits, evidence and documentation collection, and confirmation of calculations across both the design and construction stages, through to certification submission.​

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5. Is Homestar the same as Healthy Homes Standards in New Zealand?

No. Healthy Homes Standards are minimum legal requirements for rental properties. Homestar is a broader quality and performance rating system that goes well beyond minimum compliance.

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6. What Homestar rating should I aim for?

As a general guide:

• Homestar rates 6-7: Good performance and healthy living standard

• Homestar rates 8-9: Best performance practice.

• Homestar rate 10: Premium performance (World leading)

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7. Is Homestar expensive? What does it cost?

Homestar costs consist of two parts:

Consulting and modelling fees:

Pricing will vary depending on the size of the home and the complexity of the project. Please contact us to receive a tailored quote.

Physical upgrade costs:

The physical upgrade costs differ for every project. In many cases, upgrading an existing home to Homestar standards is more cost-effective than building a new home. Alternatively, designing to Homestar standards with a new build adds minimal increase to the overall cost - between 0.5% and 1.5%, according to the NZGBC. Over the long term, the energy savings achieved will help offset the initial investment, meaning the cost can be recovered over time. You can review a related study here: Financial benefits of Homestar.​​

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8. Do I need building consent for Homestar upgrades?

Some upgrades require building consent (e.g. window replacements or structural changes). Your Homestar consultant will advise which works need consent.

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