NatHERS is the star rating system that measures how much energy your home’s building envelope needs to stay comfortable. Understanding how it actually works — and what drives your rating on the Gold Coast — helps you build a better, cheaper-to-run home without spending money in the wrong places.
Related: NCC 2022 and the 7-Star Rating — for the full picture on the code changes that made 7 stars the new minimum, and what NCC 2022 means for new builds and renovations.
NatHERS stands for Nationwide House Energy Rating Scheme. It’s a computer-based assessment tool — software — that models your home’s thermal performance based on your specific design and local climate data. The result is a star rating from 0 to 10.
What NatHERS measures: the building envelope — roof, walls, windows, floors, and how they perform thermally. It models how much heating and cooling energy would be needed to keep the home within a comfortable temperature range across a full simulated year.
What NatHERS does not measure: appliances, solar panels, lighting, hot water systems. Those are covered separately under the whole-of-home energy budget introduced by NCC 2022.
Higher stars = your building envelope does more of the thermal work = less reliance on air conditioning and heating = lower running costs = more comfortable home.
Since 1 May 2024, the minimum NatHERS rating for new homes in Queensland is 7 stars — up from the previous 6-star requirement. Gold Coast is Climate Zone 2 (warm humid). The primary thermal challenge here is cooling, not heating. Our summers are long, humid, and hot; our winters are mild. A well-designed home in Climate Zone 2 can reach 8–9 stars with passive design alone, without expensive materials upgrades.
For full details on the NCC 2022 code changes and what they mean for your project, see our guide to NCC 2022 and the 7-star energy rating. For more on how building codes apply on the Gold Coast generally, see our guide to Gold Coast building codes and regulations.
A NatHERS assessment is conducted by an accredited assessor using approved software (AccuRate Sustainability or FirstRate5 are the most common tools used in Queensland). The assessor models your specific design — not a generic home, your actual floor plan, orientation, window schedule, insulation levels, and construction materials — against Gold Coast climate data.
The process works like this:
This is why NatHERS assessment works best as an iterative design tool, not a post-design compliance checkbox. When the assessor is engaged during design (not after), changes are cheap — a design decision, not a construction variation.
In Climate Zone 2, the biggest rating drivers are all about keeping heat out in summer. Here’s what matters most, in rough order of impact:
Living areas facing north capture low winter sun while the high summer sun is easily shaded by eaves. West-facing glazing is the enemy on the Gold Coast — the low afternoon sun is intense and nearly impossible to shade with fixed eaves. A home with the same construction but oriented 90 degrees differently can vary by 1–2 stars. Orientation is a design decision made early; once the slab is poured, it’s permanent.
The roof is the largest solar collection surface on a Gold Coast home. What goes on and under it matters enormously:
Windows are responsible for the majority of summer heat gain in a typical Gold Coast home. The assessment models each window individually — its size, orientation, shading, and glazing type all feed into the calculation.
R2.5 batts in external walls are now standard and make a meaningful difference, particularly on west-facing walls. The cost is modest in new construction where it’s installed before lining — typically included in standard builds now.
The Gold Coast receives reliable north-east sea breezes. A home designed with openable windows on opposing walls — particularly north-east and south-west — can flush heat from the building naturally without mechanical cooling. The NatHERS software rewards well-ventilated designs. Cross-ventilation is a layout decision: it costs nothing if considered at design stage, and is very expensive to retrofit.
Eaves of 600mm shade north-facing walls and windows from summer sun. 900mm is better. External shading devices — fixed louvres, adjustable screens, pergolas — on west-facing windows are effective but add cost. Understanding why thermal mass is important also helps with managing the relationship between shading, heat storage, and overnight cooling.
Concrete slabs and masonry walls store heat and release it slowly. In southern climates this is an asset — storing daytime winter warmth for cool evenings. On the Gold Coast, thermal mass needs careful management. A heavy masonry home with insufficient ventilation can store daytime heat and radiate it back inside at night when you want the home to cool down. NatHERS models this accurately — a high thermal mass design that’s well-ventilated scores well; one that isn’t can score poorly.
| Factor | Impact on Rating | Cost to Implement | Gold Coast Priority |
|---|---|---|---|
| Correct orientation (north-facing living) | +0.5 to +1.5 stars | Nil — design decision | Critical |
| Light-coloured roof | +0.3 to +0.7 stars | Nil — specification choice | High |
| Cross-ventilation design | +0.3 to +0.8 stars | Nil — layout decision | High |
| Ceiling insulation R6.0 (vs R4.0) | +0.3 to +0.5 stars | Low — $1,500–$3,000 | High |
| Eaves 900mm (vs 600mm) | +0.3 to +0.5 stars | Low — $2,000–$5,000 | High |
| Minimise west-facing glazing | +0.2 to +0.5 stars | Nil — design decision | High |
| Low-E glass on west/east windows | +0.2 to +0.5 stars | Moderate — $3,000–$8,000 | Medium |
| Wall insulation R2.5 | +0.2 to +0.4 stars | Low — standard in new builds | Medium |
| Reflective sarking under roof | +0.1 to +0.3 stars | Low — $1,000–$2,500 | Medium |
| Double glazing (west/east) | +0.2 to +0.4 stars | High — $8,000–$20,000+ | Low (diminishing return) |
| Triple glazing | Minimal additional over double | Very high | Not recommended for Gold Coast |
| Under-slab insulation | Minimal in warm climate | Moderate | Not recommended for Gold Coast |
Assessment costs vary with project complexity:
| Assessment Type | Typical Cost | When Used |
|---|---|---|
| Pre-assessment (during design) | $300–$500 | Early design stage — tests options before committing to details |
| Standard residential home | $500–$800 | Final design documentation stage, for BA lodgement |
| Complex home (large, multiple zones, unusual construction) | $800–$1,500 | Homes with multiple orientations, complex glazing, mixed construction types |
The pre-assessment — run during design rather than at the end — is the best investment. It typically costs $300–$500 and can prevent costly redesign if the initial design direction isn’t going to achieve the required rating. Running the assessment only after plans are complete and then discovering you need to add more insulation or change the window schedule costs more in redesign time than the pre-assessment would have.
Free wins (design decisions, no cost):
Low-cost improvements (worth doing):
Moderate investment (evaluate case by case):
Rarely worth it on the Gold Coast:
For a comprehensive guide to sustainable design strategies beyond NatHERS compliance, see our article on sustainable home design on the Gold Coast.
NCC 2022 introduced a two-part compliance requirement. The NatHERS rating addresses Part 1 — the building shell. Part 2 is the whole-of-home energy budget, which covers fixed appliances: hot water system, air conditioning, lighting, pool pumps, and on-site solar generation.
A strong whole-of-home score — for example, a good-sized solar PV system and a heat pump hot water system — can compensate for a building shell rating that’s close to but not comfortably above 7 stars. In practice, most Gold Coast homes achieve the whole-of-home budget comfortably if they have solar panels and efficient hot water. The NatHERS shell rating is usually the tighter constraint.
Note: solar panels don’t directly improve your NatHERS star rating. They improve your whole-of-home energy budget score. These are different calculations.
New habitable rooms added to an existing home must meet current NatHERS requirements. Cosmetic renovations — kitchen and bathroom upgrades, flooring, painting — generally don’t trigger energy rating requirements for the existing building. But if you’re adding floor area, changing the roofline, or significantly altering walls and windows, the new work will need to comply with NCC 2022 energy provisions. Your building designer and certifier will determine which elements apply to your specific project. See our guide on renovation costs for what different renovation types typically involve.
No — NatHERS only assesses the building envelope. Solar panels don’t affect your star rating at all. They do help with Part 2 of NCC 2022 compliance — the whole-of-home energy budget. If your building shell is strong (7+ stars) and you have solar panels plus an efficient hot water system, your whole-of-home energy budget compliance is generally straightforward.
From 7 to 8 stars, the marginal cost is usually minimal — often achievable through specification choices (roof colour, insulation upgrade) that cost little or nothing extra. The comfort improvement and running cost reduction are real and ongoing. Above 8–9 stars, the returns diminish rapidly for the Gold Coast climate. A 9-star home in our warm humid climate is significantly more comfortable than a 7-star home in theory, but the construction cost to get from 8 to 9 stars is considerably more than from 7 to 8 stars. For most Gold Coast projects, targeting 7.5–8 stars gives the best value.
A standard residential assessment takes 3–7 business days from when the assessor receives complete documentation. If changes are needed and the assessment needs to be rerun, add another few days. This is why including the NatHERS assessor in the design process early — rather than submitting final plans and waiting for a pass or fail — saves the most time overall.
Only accredited NatHERS assessors using approved software can produce a rating certificate for building approval purposes. Your building designer can recommend an accredited assessor, or you can search the NatHERS website (nathers.gov.au) for assessors by location. Design Science coordinates NatHERS assessment as part of the design and documentation process — it’s part of the approval package, not a separate exercise you have to manage yourself.
7-star NatHERS is the Gold Coast minimum for new homes. The rating assesses the building envelope — not appliances or solar. The biggest rating drivers in Climate Zone 2 are orientation, roof performance, and managing west-facing glazing — and most of these cost nothing because they’re design decisions. Assessment costs $500–$800 for a standard home, with pre-assessments during design available for $300–$500. Get the assessor involved during design, not after — it’s cheaper and produces a better result.
Design Science designs homes that consistently exceed 7 stars through passive design principles baked into the design from day one. We include NatHERS assessment coordination as part of our standard documentation process. Find out more about our sustainable home design service, or book a $280 consultation to discuss your project.
David Steadman
Licensed Builder & Building Designer
David Steadman is the founder of Design Science, a Gold Coast building design practice backed by over 30 years of hands-on construction experience. One of few Australians holding both a QBCC Builder's Licence and Building Designer licence, David brings a rare combination of design thinking and practical building knowledge to every project.
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