7 Star Energy Rating — Australia's NCC 2022 Minimum, Explained
Since the National Construction Code 2022, every new home in Australia must achieve a minimum 7-star NatHERS rating. Here's what 7 stars actually means, how to design for it, and what it costs to build.
Where 7 stars sits on the NatHERS scale
| Rating | Typical home | Heating + cooling load |
|---|---|---|
| 3 stars | Average existing Australian home | Very high — expensive bills |
| 6 stars | Pre-2022 new build (old minimum) | Moderate |
| 7 stars | NCC 2022 new build (legal minimum) | ~24% lower than 6 stars |
| 8 stars | High-performance build | Significantly lower bills |
| 9–10 stars | Passive-house style | Barely any active heating/cooling |
How to design for 7 stars
- • North-facing living areas with good eaves
- • Ceiling insulation R4.0+ (R5.0 in cooler zones)
- • Wall insulation R2.5+ continuous
- • Double-glazed or low-E windows on E/W
- • Draught sealing around doors & exhaust fans
- • External shading on summer-sun elevations
What it costs
- • Build uplift: 0.5%–3% over 6-star spec
- • Typical extra: $3,000–$15,000
- • Payback: 5–10 years on bills
- • NatHERS assessment fee: $300–$1,200
- • Plus rebate eligibility in most states
Plans stuck under 7 stars? Fix them in this order
If your first rating came back at 6.1–6.6 stars, the usual advice — double glaze every window — can add $15,000+. Work through the cheaper levers first and ask your assessor to re-model after each change.
Tier 1 · $0–$500
Spec changes, little or no material cost
- • Light roof colour (Surfmist, Dune) instead of dark
- • Ceiling fans in living areas and bedrooms
- • Tiles or polished slab in north-facing living areas
- • Doors to close off stairwells and hallways
Tier 2 · $500–$2,500
Targeted building upgrades
- • Ceiling insulation from R4.0 to R5.0–R6.0 (R-values)
- • Low-E glass on west windows only
- • Deeper eaves or louvres over north and west glass
- • Higher-rated wall batts
Tier 3 · Last resort
Costly — check Tiers 1–2 first
- • Double glazing every window ($15,000+)
- • Under-slab insulation in mild climates (it mostly pays off in cold zones like Canberra or alpine areas)
- • Major redesign of window sizes or orientation
Bridge the 7-star gap: checklist
Tick anything that describes your plans. We'll show which low-cost changes could recover stars before you pay for new windows.
Select at least one item to see a possible star gain.
Indicative only — not a rating. Star gains depend on your climate zone, orientation and design, and don't simply add up. Only a NatHERS accredited assessor re-modelling your plans can confirm a 7-star result.
Get your plans re-modelled to 7 stars
Get a NatHERS-accredited assessor to model your plans, flag any star-rating risks early, and lodge the certificate with your building permit.
7-star FAQs
What is a 7 star energy rating?
A 7 star energy rating is the minimum NatHERS thermal performance standard for new homes under the National Construction Code 2022 (NCC 2022). The home is modelled to use roughly 24% less heating and cooling energy than the old 6-star minimum. New homes must also reach a Whole of Home score of at least 60.
Is 7 stars mandatory for new homes?
Yes. Since NCC 2022 took effect (1 May 2023 in most states, with NSW and WA on their own timelines), 7 stars is the minimum NatHERS rating for new houses and apartments. A NatHERS accredited assessor must issue the certificate.
My plans came back at 6.3 stars — what should I do?
Don't jump straight to double glazing the whole house. Ask your assessor to re-model low-cost changes first: a lighter roof colour, ceiling fans, higher ceiling insulation, and Low-E glass only on unshaded west windows. Together these often recover 0.5–1 star for a few thousand dollars.
What is the cheapest way to gain stars on new plans?
Changing a dark roof to a light colour such as Surfmist is often close to free and can add 0.2–0.6 stars in warm and mixed climates. Ceiling fans and tiled or polished slab floors in north-facing living areas are also low-cost gains.
Do I need double glazing to reach 7 stars?
Often not. Many designs reach 7 stars with targeted Low-E or double glazing only on the worst west- and north-facing windows. Whole-house double glazing can cost $15,000 or more and is usually the last resort.
How much does it cost to re-model my plans?
Re-runs with your original assessor are often included or cost around $100–$250 each. A fresh assessment by a new assessor typically costs $200–$500 for a standard house — see our NatHERS assessment cost page for full pricing.
How much extra does building to 7 stars cost?
Industry estimates put the extra build cost at roughly 0.5%–3% over a 6-star spec — typically $3,000–$15,000 on a standard house — usually recovered in 5–10 years through lower bills. Smart design choices can bring this close to zero.