From 1st May 2025, all new homes and apartments in Western Australia must meet a minimum 7-star rating under the Nationwide House Energy Rating Scheme (NatHERS).
It’s a shift that reflects growing national and state-level commitments to better-performing buildings — and it places windows, glazing and framing systems squarely in the spotlight.
At the heart of the update is a simple idea: homes should use less energy to stay comfortable. And for that, how you design, position and specify windows becomes critically important.
What’s Changing in 2025?
The transition to 7-star standards is part of a national update to the National Construction Code (NCC). It sets higher expectations for thermal efficiency, particularly around building envelope performance — including walls, floors, roofs and, crucially, windows.
According to Build Australia, WA builders will be required to use higher-performing materials and smarter passive design to comply with these new benchmarks. While this represents a challenge for traditional builds, it’s also an opportunity to incorporate modern systems that reduce reliance on mechanical heating and cooling.
The Role of Windows in NatHERS Ratings
Windows are one of the most significant contributors to heat loss and heat gain in residential buildings. The WA Government notes that effective glazing, frame design and window orientation are essential to achieving good energy ratings — particularly in southern and coastal climates (Government of Western Australia).
Here’s why:
- Poorly performing windows can account for up to 40% of a home’s heat loss in winter
- In summer, up to 87% of unwanted heat gain in a typical home can come through windows
In NatHERS modelling, these factors weigh heavily. A basic aluminium-framed, single-glazed window is likely to underperform, dragging the total rating down. On the other hand, high-performance windows — including double glazing with thermally broken frames — can substantially improve results.
How Much Impact Does Glazing Have?
While energy performance depends on the full building envelope and site specifics, research and accredited energy assessors suggest that:
- Switching from single to double glazing can increase a home’s NatHERS rating by up to 1 full star
- Adding thermally broken frames can push performance further, especially in climates with high seasonal contrast or west-facing glass
The exact uplift will depend on orientation, shading, insulation and ventilation, but these two changes alone can make a measurable impact — and help offset other design constraints.
Practical Steps for Builders and Architects
Achieving 7-star NatHERS performance starts with smart early decisions — and windows are one of the most influential variables in the mix. We recommend:
- Specifying high-performance double-glazing in all habitable rooms
- Choosing thermally broken aluminium frames to prevent heat bridging at junctions
- Reviewing orientation and shading to control solar gain, particularly on west and north-west facades
- Working closely with energy assessors early to model outcomes with realistic product inputs
Choosing a window system with known thermal performance values (U-value, SHGC) also makes compliance easier and less reliant on guesswork or compromise elsewhere.
At Luxwin, we work with builders, architects and assessors to deliver compliant, high-performance window systems that meet WA’s 7-star requirements. Need glazing that’s ready for what the new standards demand? Let’s talk.