Energy · Compliance
Feb 2025
Every new house and apartment in Queensland built since 1 May 2024 has had to clear a higher energy bar than anything before it. The change is the largest single step-up in Australian residential energy regulation in a generation, and most homeowners we speak to still don't know it happened. Here's the plain-language version — what the numbers mean, what they cost to hit, and why the floor is already moving.
Two ratings, not one
NCC 2022 introduced two separate ratings that every new Class 1 home must meet:
NatHERS thermal star rating — minimum 7 stars. This measures only your building fabric: orientation, glazing, insulation, air-tightness, thermal mass. It models how hard the envelope has to work to keep occupants comfortable without mechanical help. NatHERS assessors use accredited software (AccuRate, BERS Pro, FirstRate5) to simulate annual heating and cooling load in MJ/m²/year.
Whole-of-Home rating — minimum 60 out of 100. This folds in the rest of the energy story: hot water system, cooktop, heating/cooling appliances, pool pumps, rooftop solar, and any battery. A house can hit 7 thermal stars and still flunk Whole-of-Home if its gas-cooktop-and-gas-storage-hot-water setup is dragging the operational score below 60.
You need both. A single sign-off from your assessor confirms compliance with both at design stage; the certifier checks compliance again at completion.
What "7 stars" actually buys you
In Brisbane (NatHERS climate zone 10 — subtropical), 7 stars corresponds to roughly 43 MJ/m²/year of annualised heating and cooling load — about 22% less than the previous 6-star floor and roughly half the load of a typical pre-2010 build. ClimateWorks Centre modelling suggests that translates to $400–$700 per year in cooling-and-heating energy on a typical 200 m² Brisbane home at current retail rates. The bigger savings come from Whole-of-Home: electrify the hot water, ditch the gas cooktop, size solar generously, and you can drop lived utility cost below $1,000 a year on a four-bedroom home.
What it costs to build
The Housing Industry Association initially projected $20,000+ added build cost for 7 stars; subsequent federal modelling put it closer to 1–3% of base build cost when designed in from concept stage. On a $700,000 home, that's $7,000–$21,000 to gain $500/year in perpetuity — a 4–6 year simple payback, before considering rising energy prices. Where the cost balloons is when builders try to bolt performance onto a poorly-oriented design with feature glazing facing west: rectifying that with thermally-broken double-glazed aluminium can run $25,000+ on one elevation.
The design moves that get you there
Five things that consistently push a Brisbane house past 7 stars without forcing exotic spec:
Living rooms within 20° of true north, with 600 mm horizontal eaves above primary north glazing.
R5.0 ceiling insulation and a light-coloured or solar-reflective roof.
Glazing upgrade where it counts — thermally broken aluminium or uPVC frames, double-glazed, low-E on west and east elevations.
Sealed junctions and penetrations. Brisbane construction commonly leaks at 15 ACH at 50 Pa; getting to 5 ACH is cheap and worth half a star.
Cross-ventilation as the design default — operable openings on opposing walls of every habitable room.
Why this is the floor, not the ceiling
The Energy Ministers' Trajectory for Low Energy Buildings sets a path toward 8 stars and a tighter Whole-of-Home threshold in NCC 2028. Mandatory disclosure of energy ratings at point of sale is already law in the ACT and being consulted on in Victoria. Within five years, a 7-star home will look ordinary on the market; an 8-star home will trade at a premium; a 9-star, near-net-export home will be the new aspirational tier. Designing today to hit 7 stars exactly means designing to a code your house won't satisfy by the time the kids are in high school.
Embodied carbon — coming next
NCC 2025 introduced voluntary embodied carbon reporting for commercial buildings. Residential will follow in NCC 2028 or 2031. Embodied carbon is the emissions baked into the materials before anyone flips a light switch — concrete, brick, steel, aluminium. Material substitutions that look cosmetic today will be compliance choices tomorrow. Specifying a timber-framed home with recycled-content insulation and lighter-mass construction now is buying compliance headroom for a regulation that hasn't been written yet.
What this means for your project
If you're commissioning a design in 2026, ask three things of whoever's drawing your house:
What's the modelled NatHERS rating and where does it land on the climate zone 10 scale?
What's the modelled Whole-of-Home rating and which appliances are doing the work?
What's the air-leakage target and is it documented in the specification?
If the answers come back vague, you're being designed a 7.0-star house — exactly minimum, no headroom, ready to look dated in 2030.
If you'd like us to model your concept and tell you what star rating it lands on before you commit to a builder, get in touch.
By Ashton Genrich — Building Design — Open, QBCC 15387939