Designing for 7 Star NatHERS on a Budget

Achieving a 7-star NatHERS rating is now a standard requirement for most new homes under the National Construction Code (NCC 2022).

The challenge is no longer whether to reach 7 stars — but how to do it efficiently, without unnecessary cost.

In most cases, higher performance does not come from adding more to a design, but from making better decisions early.

Why cost issues happen

Projects often run into cost increases when energy performance is considered too late.

At that point, options become limited and may include:

• Upgrading glazing or insulation beyond initial allowances
• Redesigning layouts or window placements
• Adding shading or mechanical systems as a fix

These changes can be expensive because they are reactive rather than planned.

Performance starts with design

The most effective way to achieve a 7-star rating is through the building’s design — not additional features.

Key elements that influence performance include:

• Orientation of the home relative to the sun
• Window placement and size
• Shading and eaves
• Insulation and construction type
• Internal layout and zoning

When these are resolved early, strong performance can often be achieved without increasing construction cost.

Orientation has the biggest impact

Orientation is one of the most influential factors in a NatHERS rating.

A well-oriented home can:

• Capture winter sun for natural warmth
• Reduce summer heat gain
• Improve overall comfort without relying on mechanical systems

Because orientation is difficult to change later, it should be considered from the earliest stages of design.

Glazing and shading work together

Windows play a critical role in energy performance.

Rather than simply increasing glazing performance (which can add cost), the focus should be on:

• Positioning windows appropriately
• Using shading to control solar gain
• Balancing daylight with thermal performance

Small adjustments in these areas can significantly improve results.

Design over add-ons

One of the most common misconceptions is that higher energy ratings require additional systems or upgrades.

In reality, NatHERS assessments focus on the building’s design and fabric — not appliances or occupant behaviour.

This means:

• Performance comes from how the building is designed
• Not from what is added later

A well-designed home can often achieve 7 stars with minimal additional cost.

Timing matters

The earlier energy performance is considered, the easier it is to optimise.

Engaging with NatHERS assessments during the design phase allows for:

• Testing different design options
• Identifying performance gaps early
• Avoiding costly redesign

Late-stage assessments often limit flexibility and increase cost.

Working with the right consultant

An experienced energy rating consultant can help guide design decisions and identify efficient pathways to compliance.

Rather than simply producing a report, a good consultant will:

• Work alongside the design team
• Suggest practical improvements
• Focus on performance outcomes, not just compliance

Key takeaway

Achieving a 7-star NatHERS rating does not need to increase your build cost.

In most cases, the outcome depends on:

• Early design decisions
• Understanding key performance drivers
• Integrating energy performance into the design process

When these are aligned, compliance becomes a natural result of the design — not an added constraint.

If you need to understand requirements, process and costs:

→ 7 Star NatHERS Certificate — what you need to know