What Is a NatHERS Certificate?
Costs, what's included, and how to get one — the complete 2026 guide to Australia's home energy rating certificate
Taylor M
NatHERS & Home Energy Specialist
Key Takeaways
- •A NatHERS certificate rates your home's thermal performance from 0–10 stars
- •Only certificates from NatHERS-accredited assessors are legally valid
- •New builds must achieve a minimum 7-star rating under NCC 2022
- •Certificates cost $300–$700 depending on home complexity
- •The ACT requires disclosure at sale; NSW is piloting a voluntary scheme
- •The new existing homes certificate includes personalised upgrade guidance
What Is a NatHERS Certificate?
A NatHERS certificate is the official document that records how thermally efficient your home is. It's produced using software accredited by the Nationwide House Energy Rating Scheme (NatHERS), which is administered by the CSIRO on behalf of the Australian Government.
The certificate measures how much energy your home needs for heating and cooling to maintain comfortable temperatures year-round. The result is expressed as a star rating from 0 to 10 — where 10 stars means the home needs virtually no artificial heating or cooling.
Think of it as your home's thermal performance report card. Just as a car has a fuel efficiency rating, your home has a NatHERS star rating that tells you (and potential buyers) how energy-efficient the building envelope is.
Want a quick estimate? Try our free energy rating calculator — it takes under 2 minutes.
Get Your EstimateWhat Does a NatHERS Certificate Contain?
A NatHERS certificate contains far more than just a star number. Here's what you'll find on a standard certificate:
Thermal Star Rating (0–10)
The headline figure. Measures heating and cooling energy loads. Each star represents a specific energy use threshold in MJ/m²/year for your climate zone.
Whole of Home Score (0–100)
Introduced with NCC 2022, this broader score accounts for heating, cooling, hot water, lighting, pool pumps, and renewable energy. Required for new builds alongside the star rating.
Heating & Cooling Loads
Separate energy figures (MJ/m²/year) for heating and cooling. Shows whether your home loses more energy in winter or summer — critical for targeting upgrades.
Climate Zone & Assessor Details
Your NatHERS climate zone (Australia has 69), the accredited assessor's name and registration number, the software used, and the assessment date.
New for Existing Homes
The new existing homes certificate format (agreed March 2026 under the expanded NatHERS delivery model) includes something most competitors don't mention: personalised upgrade recommendations with estimated star rating improvements for each upgrade. This means you don't just learn your current rating — you get a prioritised action plan showing which improvements (insulation, glazing, draught sealing) will give you the biggest return.
New Build Certificate vs Existing Homes Certificate
This is one of the most confusing parts of the NatHERS system — and most articles online don't explain it clearly. There are two distinct types of NatHERS certificate, and they're produced through different processes for different purposes.
| Aspect | New Build Certificate | Existing Homes Certificate |
|---|---|---|
| Purpose | Demonstrate the home will meet the National Construction Code before it's built | Show the current performance of an existing dwelling and how to improve it |
| When it's done | During the design phase, before council approval | Any time — typically before sale, renovation, or upgrade planning |
| How it's assessed | From architectural plans and specifications (no site visit needed) | On-site inspection — measurements, insulation checks, glazing audit, photos |
| Minimum standard | Must achieve 7 stars + Whole of Home score (NCC 2022) | No minimum — reports actual performance as-is (often 1.5–4 stars) |
| What's included | Star rating, Whole of Home score, heating/cooling loads, plans-as-assessed | Star rating + personalised upgrade recommendations with estimated rating uplift per upgrade |
| Required for | Council building approval, all new dwellings nationwide | ACT property sales (mandatory), NSW (voluntary pilot), upgrade planning |
| Typical cost | $300–$700 | $200–$500 |
| Turnaround | 3–10 business days after plans received | 3–7 business days after site visit |
The most important practical difference: a new build certificate proves a home will perform to a standard, while an existing homes certificate measures how it actually performs today and tells you exactly what to fix. They're not interchangeable — if you bought a 30-year-old home with a "7-star certificate" from when it was built, that doesn't reflect its current condition after decades of wear, modifications, or insulation settling.
For more on the new existing homes pathway introduced in March 2026, see our guide on the NatHERS existing homes assessment.
Accredited Certificate vs Non-Accredited Report
This distinction is critical and often misunderstood. Not all energy assessments are created equal.
| Feature | Accredited NatHERS Certificate | Non-Accredited Report |
|---|---|---|
| Legal standing | ✅ Valid for building approvals & compliance | ❌ No legal standing |
| Council submissions | ✅ Accepted by all councils | ❌ Will be rejected |
| Property sales | ✅ Meets disclosure requirements (ACT mandatory, NSW pilot) | ❌ Does not satisfy legal obligation |
| Software | CSIRO-accredited (FirstRate5, BERS Pro, etc.) | May use any methodology |
| Assessor | NatHERS-registered, audited by accrediting body | No formal oversight |
| Typical cost | $300–$700 | $100–$300 |
Bottom line: If you need a certificate for building approval, property sale, or any official purpose — it must be from a NatHERS-accredited assessor. A cheaper non-accredited report might be useful for personal interest, but it won't satisfy any legal requirement.
Take the Next Step
Whether you're curious about your home's efficiency or ready to get a professional assessment, we have tools to help.
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Use our free calculator to get an instant estimate of your home's energy star rating.
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When Do You Need a NatHERS Certificate?
Building a New HomeRequired
All new residential buildings must achieve a minimum 7-star NatHERS thermal rating under NCC 2022. Your builder will need the certificate before council approves the plans. The assessment should be done during the design phase — not after construction.
Major RenovationsRequired
If your renovation triggers NCC compliance (typically structural changes, extensions, or changes affecting the building envelope), you'll need a NatHERS assessment for the affected areas. Minor cosmetic renovations don't require one.
Selling a Property in the ACTRequired
The ACT has required mandatory energy disclosure at point of sale since 1999. You must provide an energy efficiency rating (EER) to prospective buyers. An accredited NatHERS certificate satisfies this requirement.
Selling a Property in NSW (Voluntary Pilot)Voluntary
NSW has launched a voluntary energy disclosure pilot, with plans to make it mandatory. Sellers can choose to include a NatHERS rating on listings. Getting one now positions you ahead of the mandate. See our full guide on energy ratings for selling in NSW.
Existing Home Assessment (Voluntary)Voluntary
Want to know your current rating and what upgrades would improve it? The new NatHERS existing homes pathway (expanded March 2026) makes this easier and more affordable. The certificate includes upgrade recommendations — perfect before planning renovations.
Marketing a Rental or Sale PropertyVoluntary
Even where not legally required, a good NatHERS rating is a selling point. Homes with higher ratings sell for up to 10% more according to CSIRO research. Including the certificate in your listing adds credibility.
State-by-State: Where Is a NatHERS Certificate Required?
Requirements vary significantly across Australia. Here's the current status for property sales and new builds in each state and territory:
| State/Territory | New Builds | Sale Disclosure | Status |
|---|---|---|---|
| ACT | ✅ Required (7 stars min) | ✅ Mandatory since 1999 | Mandatory |
| NSW | ✅ Required (7 stars min) | 🟡 Voluntary pilot (moving to mandatory) | Pilot |
| VIC | ✅ Required (7 stars min) | ❌ Not required | New builds only |
| QLD | ✅ Required (7 stars min) | ❌ Not required | New builds only |
| SA | ✅ Required (7 stars min) | ❌ Not required | New builds only |
| WA | ✅ Required (7 stars min) | ❌ Not required | New builds only |
| TAS | ✅ Required (7 stars min) | ❌ Not required | New builds only |
| NT | ✅ Required (7 stars min) | ❌ Not required | New builds only |
Note: All states require NatHERS certificates for new builds under the National Construction Code (NCC 2022). The table above highlights the additional sale disclosure requirements. Victoria previously used the Residential Efficiency Scorecard but is transitioning to NatHERS following the Scorecard program's scheduled closure in June 2026.
Can You Get a NatHERS Certificate Online?
This depends on whether it's a new build or an existing home:
New Builds — Yes, Remotely
New build assessments are based on architectural plans and specifications. You email your plans to an assessor, they model the home in accredited software, and deliver the certificate digitally. No site visit needed — the entire process can be done remotely.
Existing Homes — Site Visit Required
Existing home assessments require an on-site visit. The assessor needs to measure rooms, inspect insulation, check glazing types, note construction materials, and photograph key features. This can't be done from photos or floor plans alone. The visit typically takes 1–2 hours.
In both cases, the certificate itself is delivered digitally (PDF). You can find and contact assessors online through our assessor directory, and the booking process is straightforward — but for existing homes, someone needs to physically visit the property.
Ready for an official assessment? Find certified NatHERS assessors in your area.
Find Local AssessorsHow to Read Your NatHERS Certificate
NatHERS certificates can look technical. Here's how to interpret each section:
1. The Star Rating
The big number — your thermal performance score from 0 to 10. Each full star represents a meaningful reduction in heating and cooling energy. A 7-star home uses roughly half the energy of a 5-star home. For a detailed breakdown of what each star level means, see our NatHERS star rating scale guide.
2. Whole of Home Score (NCC 2022+)
A score from 0 to 100 that goes beyond thermal performance. It factors in hot water systems, lighting, plug loads, pool pumps, solar PV, and batteries. A home with a 7-star thermal rating might score 60 or 80 on the Whole of Home scale depending on its appliances and renewable energy systems. New builds must meet both thresholds.
3. Heating & Cooling Energy Loads
Expressed in MJ/m²/year (megajoules per square metre per year). Lower is better. The split between heating and cooling tells you where your home loses the most energy. A home with high cooling loads but low heating loads probably needs better shading or glazing, while high heating loads suggest insulation gaps.
4. Climate Zone
Australia has 69 NatHERS climate zones. Your certificate shows which zone your home is in, because the same house design would get different star ratings in Darwin (hot/humid) versus Hobart (cool/temperate). This is why you can't directly compare certificates from different locations without accounting for climate zone.
5. Upgrade Recommendations (Existing Homes)
The new existing homes certificate format includes a section that most people don't know about: prioritised upgrade guidance. It shows you which specific improvements (ceiling insulation, double glazing, draught sealing, wall insulation) would give the biggest star rating improvement, helping you invest your renovation budget where it matters most.
What Does Your Star Rating Actually Mean for Your Bills?
The star number on your certificate isn't just a score — it's a direct predictor of how much you'll spend on heating and cooling each year. Here's how the scale translates to real-world energy use and household bills (based on a typical 180m² home, indicative figures from CSIRO modelling).
| Star Rating | What It Means | Indicative Annual Heating & Cooling Cost |
|---|---|---|
| 0–2 stars | Pre-1990s uninsulated home. Hot in summer, cold in winter, very expensive to heat or cool. | $2,500–$4,000+ |
| 2.5–3.5 stars | Australian existing-home average is around 1.8–2.9 stars. Below average — basic insulation, single glazing, draughty. | $1,800–$2,800 |
| 4–5 stars | Old minimum for new builds (pre-2010). Reasonable insulation but significant room for improvement. | $1,200–$1,800 |
| 6 stars | Previous national minimum (2010–2022). Decent thermal performance, comfortable most of the year. | $800–$1,400 |
| 7 stars | Current national minimum for new builds (NCC 2022). Roughly half the heating/cooling energy of a 5-star home. | $500–$1,000 |
| 8–9 stars | High-performance home. Excellent insulation, double glazing, careful orientation, minimal draughts. | $200–$600 |
| 10 stars | "Net zero ready" — the home needs virtually no artificial heating or cooling to stay comfortable. | Under $200 |
So what does a 2.9-star rating mean?
It means your home sits roughly at the Australian existing-home average. You're likely paying $1,800–$2,800 per year on heating and cooling — and there's a clear path to cut that significantly. Moving from 2.9 to 5 stars typically saves $700–$1,500 per year in energy costs, and the most cost-effective upgrades are usually ceiling insulation, draught sealing, and pelmets/curtains for windows. The existing homes certificate tells you exactly which upgrades will move your rating the most.
What's a "good" score? For existing homes, anything above 5 stars is well above average. For new builds, 7 stars is the legal minimum and 8+ is genuinely high-performance. Use our savings calculator to estimate what an upgrade could save on your specific home.
How Much Does a NatHERS Certificate Cost?
Certificate costs vary based on the type of assessment, home complexity, and location. Here's what to expect in 2026:
New Build (Simple)
$300–$450
Single-storey, standard design. The most common assessment type.
Typical turnaround: 3–5 days
New Build (Complex)
$450–$700
Multi-storey, unusual geometry, or high-performance targets.
Typical turnaround: 5–10 days
Existing Home
$200–$500
New pathway under expanded NatHERS delivery model. Includes upgrade recommendations.
Typical turnaround: 3–7 days
For a deeper dive into pricing factors and how to get the best value, see our detailed NatHERS certificate cost guide.
NatHERS Certificate Cost by State (2026)
Pricing varies by state due to differences in assessor supply, travel distances, and local compliance requirements. These are typical ranges for a standard single-storey home:
| State / Territory | New Build | Existing Home | Notes |
|---|---|---|---|
| NSW | $330–$600 | $350–$550 | BASIX certificate also required for new builds |
| VIC | $300–$550 | $300–$550 | Scorecard closing 23 June 2026 — switching to NatHERS |
| QLD | $300–$500 | $300–$500 | QDC 4.1 condensation rules apply |
| SA | $300–$550 | $320–$520 | Competitive Adelaide market |
| WA | $350–$650 | $380–$600 | Higher cost outside Perth metro |
| TAS | $320–$600 | $320–$550 | Smaller assessor pool — book early |
| ACT | $350–$600 | $350–$600 | Mandatory disclosure at sale since 1999 |
| NT | $400–$700 | $400–$650 | Limited assessor availability |
Prices are indicative ranges for a standard single-storey home (~150–200 m²). Multi-storey, complex, or large homes can cost 30–80% more. Travel surcharges may apply for properties outside metro areas.
What Affects the Cost of a NatHERS Certificate?
- •Floor area & storeys: Each additional storey roughly adds $80–$150 to the assessment fee.
- •Design complexity: Unusual geometry, large glazed areas, and split-level designs require more modelling time.
- •Plan readiness: Complete, dimensioned architectural plans = lower fee. Hand-drawn or incomplete plans = higher fee (assessor needs to redraw).
- •Location: Metro pricing is competitive; regional and remote properties attract travel surcharges of $50–$200.
- •Assessment type: New build (from plans) is usually cheaper than an existing home assessment, which requires an on-site inspection.
- •Turnaround time: Standard turnaround is 3–7 days; 24–48 hour rush services typically add a 25–50% surcharge.
Tip: Always get two or three quotes — pricing for the same job can vary by 30%+ between assessors. Use our free assessor finder to compare local NatHERS-accredited professionals near you.
How Long Is a NatHERS Certificate Valid?
For new builds: The certificate remains valid as long as the home is built according to the assessed plans. There's no formal expiry. However, if you change the plans after certification — adjusting window sizes, moving walls, changing insulation specifications — you'll need a new or amended assessment.
For existing homes: The certificate reflects the home's condition at the time of assessment. It doesn't expire per se, but any significant renovation, deterioration, or upgrade would change the actual thermal performance. If you're selling a property and using the certificate for disclosure, buyers and agents will expect a reasonably recent assessment.
Practical recommendation: If your certificate is more than 3–5 years old and you've made changes to the building envelope, consider getting a reassessment — especially if you're selling or planning further renovations.
How to Get Your NatHERS Certificate
Find an accredited assessor
Use our assessor directory to find NatHERS-accredited assessors in your area. Check their accreditation status, reviews, and specialisation.
Provide your plans or arrange an inspection
For new builds, send your architectural plans and specifications. For existing homes, the assessor will arrange a site visit to measure and document your home.
Assessment is modelled
The assessor inputs your home's details into CSIRO-accredited software (FirstRate5, BERS Pro, or equivalent) which calculates the thermal performance for your specific climate zone.
Receive your certificate
You'll receive the official NatHERS certificate with your star rating, energy loads, and (for existing homes) upgrade recommendations. Turnaround is typically 3–10 business days.
Ready to get your NatHERS certificate?
Find an Accredited Assessor Near YouFrequently Asked Questions
Official Resources:
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