Energy Efficiency
WERS Ratings & NCC Window Compliance Explained
U-values, SHGC, WERS and NCC energy requirements decoded — what the numbers mean and what your Melbourne build or renovation actually needs.
If you are building or renovating in Victoria, your windows have to meet energy requirements — and the alphabet soup of WERS, U-values, SHGC and NCC stars confuses almost everyone. Here is what actually matters.
The two numbers that matter
- U-value: how well the whole window insulates. Lower is better — a lower U-value means less heat escaping in winter and less entering in summer.
- SHGC (Solar Heat Gain Coefficient): how much solar heat the window lets through. Lower blocks more heat (good for west-facing summer sun); higher lets warmth in (sometimes wanted on south-facing winter rooms).
The right numbers depend on orientation and climate zone — there is no single "best". A good window supplier helps you balance U-value and SHGC per elevation.
What WERS is
WERS (Window Energy Rating Scheme) is the independent scheme that rates windows for energy performance so the figures are comparable and trustworthy. WERS-rated windows give your building surveyor and energy assessor the documented U-value and SHGC they need to sign off your design.
NCC and the 7-star requirement
The National Construction Code sets minimum energy performance for new homes and major renovations, and Victoria now works to a 7-star standard for new dwellings. Windows are a major part of that calculation — which is why builder-basic single glazing often fails modern energy reports, and why double glazed or thermally broken systems are increasingly standard on new builds.
How we help
Our aluminium systems are fabricated from Alspec profiles designed and tested to Australian Standards (AS2047 for windows, AS1288 for glazing), with WERS-rated and thermally broken options. Send us your energy report or architectural schedule and we will confirm the systems and glass build-ups that comply — no guesswork at surveyor sign-off.
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Common questions
Frequently asked
Lower is better for insulation. Your energy report specifies the target for your design; double glazed and thermally broken systems achieve much lower U-values than single-glazed aluminium.
WERS ratings give assessors documented, comparable performance figures. Using WERS-rated windows makes NCC compliance and surveyor sign-off straightforward.
Victoria's 7-star standard for new homes raises the energy bar, and windows are a big part of the calculation. It typically means double glazing and sometimes thermally broken frames to comply.
Yes. Send your energy report or schedule and we spec Alspec systems and glazing that meet the required U-value and SHGC, with documentation for handover.
Keep reading
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