Navigating BASIX & NCC 2022: How NSW 7-Star Rule Changed Window Specs

If you're building or renovating in NSW right now, there's a good chance someone has mentioned BASIX, NCC 2022, or the 7-star energy rating in the same breath as your window choices. These terms can be confusing, especially with recent changes.

The rules changed significantly in October 2023. Windows are now one of the most scrutinised parts of any new home or major renovation. Here's what you need to know.

Quick Answer

• NCC 2022 lifted the minimum energy rating for new homes in NSW from 6 to 7 stars under the Nationwide House Energy Rating Scheme (NatHERS).
• BASIX is NSW's state-level compliance tool. It now sets stricter thermal comfort targets that align with the 7-star requirement.
• Windows are a primary lever for hitting those targets; standard single-glazed aluminium frames almost never cut it anymore.
• 7-star windows (typically double-glazed with thermally broken frames) are now the practical standard for most Sydney and NSW builds.
• Getting your window spec right early saves costly redesigns or compliance failures later.

What Is BASIX, and Why Did It Change?

BASIX, the Building Sustainability Index, is the NSW Government's online assessment tool that every new home and significant renovation must pass before a development application is approved. It checks three things: water efficiency, energy use, and thermal comfort.

For years, BASIX thermal targets were set to broadly align with a 6-star NatHERS rating. Then NCC 2022 came into effect, raising the floor to 7 stars. NSW adopted it in October 2023, and the thermal comfort requirements in BASIX tightened accordingly.

A 7-star home uses roughly 25% less energy for heating and cooling than a 6-star equivalent.

How Windows Factor Into Your Star Rating

A window is the weakest point in almost any wall.

A well-insulated external wall might have an R-value of 2.5 or higher. A standard single-glazed aluminium window? Closer to R0.2. NatHERS software sees that gap clearly. Every window on every elevation is modelled individually, including its size, orientation, frame type, and glass type.

Three things matter most under the new rules:

1. U-value measures how much heat passes through the window. Lower is better. Single glazing typically has a U-value of 5.5–6.0 W/m²K. Double-glazed windows in Sydney commonly achieve 1.5–3.0 W/m²K. The NCC 2022 requirements effectively make anything above 3.5 difficult to work with in most orientations.
2. SHGC (Solar Heat Gain Coefficient) measures how much solar radiation enters as heat. North-facing windows can benefit from a higher SHGC in winter. West- and east-facing glass generally needs a lower SHGC to limit summer overheating. Good window specification matches SHGC to orientation rather than applying one number across the whole house.
3. Frame conductivity is the part most people miss. A double-glazed unit in a standard aluminium frame loses much of its insulation benefit through the frame itself. Thermally broken frames (which interrupt the heat path through the aluminium) significantly improve whole-of-window performance. uPVC frames go further again.

What "7-Star Windows" Means in Practice

There's no single product called a "7-star window." The star rating applies to the whole home, not to individual components. But in practice, certain window specifications make it dramatically easier to reach 7 stars, and others make it nearly impossible.

For most Sydney builds, 7-star window specifications look something like this:

• Double-glazed units with a 12–16mm argon gas gap
• Low-E (low emissivity) glass coating on at least one pane to reduce radiant heat transfer
• Thermally broken aluminium frames, or uPVC frames
• Whole-of-window U-values in the range of 1.8–2.8 W/m²K
• SHGC values selected by orientation (typically 0.4–0.6 for north, 0.2–0.4 for east/west)

Single-glazed windows in standard aluminium frames are still technically permitted, but achieving BASIX compliance with them usually requires heavy compensating elsewhere, such as extra insulation, reduced glazing area, or extensive fixed shading. For most designs, that's neither practical nor what the client wants.

Early vs Late Specification: Why Timing Matters

Windows typically enter the BASIX process in one of two ways, and the difference in outcome is significant.

• Early specification is the right approach. Your designer works with an energy assessor during the design phase to model different glazing options. You find out the proposed west-facing living room window needs a lower SHGC before you've committed to any product. Changes at this stage cost nothing.
• Late specification is where costs can get high. Plans are submitted with windows described generically; the BASIX assessment fails the thermal comfort test, and the response is to upgrade the glazing spec, sometimes after window sizes have been locked in and structural elements sized around the openings.

A good energy assessor will push for early decisions on glazing. So will a window supplier who understands how BASIX compliance works.

Does This Apply to Renovations?

Yes, if the work reaches the $50,000 threshold for residential alterations and additions. When BASIX is triggered, the thermal comfort assessment covers the whole dwelling, not just the new work. That means an extension to a home with existing single-glazing may require upgrading the original windows to improve overall performance.

For work under that threshold, BASIX doesn't apply, but the NCC still does for anything requiring a construction certificate.

What Works for Sydney Homes

Sydney's mixed climate means your windows need to work in both directions: limiting heat gain in summer and retaining warmth in winter. What works for Sydney homes generally comes down to double glazing as a baseline, Low-E coatings selected by orientation, thermally broken or uPVC frames, and appropriate external shading on east and west elevations.

The 7-star requirement has made these good practices into minimum standards. For most homeowners, that's not a bad outcome. A well-specified home is more comfortable, quieter, and cheaper to run all year. Learn more about 7-star window savings here.

Getting Your Windows Right From the Start

At Integra Windows, we manufacture double-glazed uPVC windows in Sydney using European technology, and we can provide the performance data your energy assessor needs. If you're unsure whether your current glazing spec will meet BASIX thermal comfort requirements, it's worth a conversation before you commit.

Talk to our team about your project, or find out more about window installation in Sydney and how much you could save with 7-star-compliant windows.

Want to know how Integra supports BASIX compliance? Learn more here.