Recycled Bricks & the 7-Star Energy Rating: What Australian Builders & Homeowners Need to Know

Yes, recycled clay bricks are recognised as a high-thermal-mass material under Australia’s NatHERS assessment system and actively support 7-star NCC compliance by reducing heating and cooling loads. Because they bypass the kiln-firing process, they also carry significantly lower embodied carbon than new bricks, approximately 0.5 kg CO₂ avoided per reused brick.

Introduction: A New Standard for Every New Home in Australia

If you’re planning to build or significantly renovate in 2026, you’ve almost certainly heard the phrase “7-star energy rating.” It shows up in your builder’s quote, in your planning documents, and increasingly in conversations with architects.

But here’s a question most builders and homeowners don’t think to ask: does my choice of brick affect whether I reach that 7-star rating?

The answer is yes – more than you might expect.

Australia’s National Construction Code (NCC 2022) now mandates a minimum 7-star NatHERS thermal rating for new homes across most states. Meeting that standard requires getting smarter about your building’s thermal shell: the walls, floor, roof, and windows that determine how much energy your home burns just to stay comfortable.

Recycled clay bricks, particularly the dense, hand-made Australian bricks salvaged by The Brick Pit from demolitions across the country are among the highest-performing thermal mass materials available. And unlike new bricks, they arrive at your site having already paid their carbon debt once.

This guide explains exactly how recycled bricks and the 7-star energy standard intersect so you can make confident, code-compliant, and genuinely sustainable decisions on your next build.

What Is the 7-Star NatHERS Energy Rating?

NatHERS stands for the Nationwide House Energy Rating Scheme. It’s the system Australia uses to measure how much energy a home needs for heating and cooling. Homes are rated from 0 to 10 stars the higher the stars, the less energy the thermal shell requires to maintain comfortable indoor temperatures.

Under NCC 2022:

• New houses and townhouses must achieve a minimum of 7 stars NatHERS, plus a Whole-of-Home energy budget score of at least 60 out of 100
• New apartments must achieve an average of 7 stars across all units (no individual unit below 6 stars), with a Whole-of-Home score of at least 50 out of 100
  

That one extra star moving from 6 to 7 is a meaningful lift. A 7-star home uses approximately 20–25% less energy for heating and cooling than a 6-star home, which means lower running costs, better comfort during heatwaves and cold snaps, and a reduced carbon footprint over the home’s lifetime.

State-by-State NCC 2022 Adoption Timeline

Important: In NSW, compliance runs through BASIX (not NatHERS directly), but the thermal performance targets are aligned with the 7-star equivalent. The compliance pathway differs, but the outcome standard is comparable.

No further residential energy efficiency changes are planned under NCC 2025; the 7-star framework is what builders and designers will be working to for the foreseeable future, with no move to 8 stars before at least mid-2029.

What Is Thermal Mass and Why Do Recycled Bricks Excel at It?

To understand why recycled bricks matter to your energy rating, you need to understand thermal mass.

Thermal mass is a material’s ability to absorb heat, store it, and release it slowly over time. In a well-designed home, high-thermal-mass walls absorb heat during the day (keeping the interior cool) and release it at night (keeping the interior warm). Done right, this natural buffering effect dramatically reduces how hard your heating and cooling systems have to work which is exactly what NatHERS measures and rewards.

Dense fired clay bricks which is what most Australian recycled bricks are are one of the best thermal mass materials in common construction. Key properties:

• Thermal conductivity: approximately 0.6–1.0 W/m·K (moderate good for slow heat transfer)
• Density: typically 1,600–2,000 kg/m³ (high more mass = more heat storage capacity)
• Specific heat capacity: approximately 800–900 J/kg·K
  

A double brick wall made from recycled clay bricks provides thermal mass on both sides of the wall cavity, making it particularly effective at stabilising interior temperatures. Energy assessors and NatHERS software explicitly recognise double brick construction as a high-thermal-mass configuration that can contribute meaningfully to achieving a 7-star rating, especially in temperate climate zones (Climate Zones 4–7, covering most of Sydney, Melbourne, Adelaide, Canberra, and Perth).

How This Affects Your NatHERS Score

NatHERS software (AccuRate, FirstRate5, BERSPro) models your home’s thermal performance by analysing wall materials, orientation, glazing, insulation, shading, and climate zone. When high-thermal-mass materials like recycled clay bricks are specified:

1. The model simulates slower heat gain in summer → lower cooling demand
2. The model simulates slower heat loss in winter → lower heating demand
3. Both effects reduce the annual energy load → pushing the star rating up
   

In practice, specifying recycled double brick walls paired with correct building orientation and appropriate glazing can push a borderline 6.5-star home to 7 stars or beyond without requiring additional insulation upgrades.

Learn more about how recycled bricks perform across Australian climate zones in our guide to recycled bricks and thermal efficiency in Australian homes.

The Embodied Carbon Advantage: A Number That Matters

Meeting a 7-star rating covers operational energy , the energy used to run your home. But sustainability-conscious builders, architects, and specifiers are increasingly looking at the full picture: embodied carbon, the carbon emitted during the manufacture, transport, and installation of building materials.

This is where recycled bricks have a compelling, data-backed advantage.

Manufacturing a new fired clay brick produces approximately 0.41 kg of CO₂ per brick. The kiln-firing process, which requires sustained temperatures of 900–1,200°C, accounts for the bulk of this.

When a brick is recycled, that kiln-firing carbon has already been emitted decades or a century ago. The only carbon involved in a recycled brick is the cleaning, transport, and any re-pointing work. Lifecycle assessment research shows:

Reusing a single brick avoids approximately 0.5 kg CO₂ compared to manufacturing a new one. For a typical Australian home using 16,000 bricks, choosing recycled bricks avoids approximately 8 tonnes of CO₂ in embodied emissions. (Source: Ecochain lifecycle assessment benchmarks)

To put that in perspective: 8 tonnes of CO₂ is roughly equivalent to driving a petrol car for two years.

This embodied carbon saving is increasingly recognised in Green Star and NABERS assessments, and it contributes to whole-of-life sustainability goals that complement NatHERS operational performance.

For a deeper look at how recycled bricks support Green Star certification, read our article on the SBRC at the University of Wollongong — Australia’s first 6-Star Green Star certified building, which used recycled brick materials in its construction.

Recycled Bricks, BASIX, and Green Star: The Full Sustainability Picture

BASIX (New South Wales)

NSW uses BASIX the Building Sustainability Index rather than NatHERS directly. Enhanced BASIX (active from October 2023) sets thermal performance targets equivalent to 7 stars. Recycled clay bricks contribute to BASIX compliance in the same way they contribute to NatHERS by providing thermal mass that reduces heating and cooling loads modelled by the BASIX assessment tool.

Additionally, choosing recycled bricks can contribute to BASIX’s water and energy sections by reducing the embodied resource demand of your project.

Green Star (Green Building Council of Australia)

For commercial or high-end residential projects pursuing Green Star certification, recycled bricks contribute across several credit categories:

• Materials category: Recycled and reused materials credits
• Responsible sourcing: Locally sourced Australian materials (The Brick Pit sources exclusively from Australian demolitions)
• Embodied carbon reduction: Demonstrated CO₂ savings from material reuse
  

The Brick Pit’s bricks have been specified in Green Star-rated projects, including the Sustainable Buildings Research Centre at the University of Wollongong the first building in Australia to receive both 6-Star Green Star certification and Living Building Challenge certification.

A Note on Structural Compliance

Recycled bricks used in structural applications must comply with AS 3700: Masonry Structures. All bricks supplied by The Brick Pit through its Brick Rescue® quality process are individually inspected and graded to ensure structural suitability. This means your certifier or building surveyor can be confident that The Brick Pit’s Face Grade, Combo Grade, and Paving Grade products meet the relevant Australian Standards for their intended use.

How to Specify Recycled Bricks for a 7-Star Compliant Home:

A Practical Guide

Getting the most from recycled bricks’ thermal mass properties requires working with your energy assessor early. Here’s the process:

Step 1: Engage a NatHERS Assessor at Design Stage

Don’t leave the energy rating to the end of design. A NatHERS assessor can model different wall configurations including recycled brick thickness, cavity sizing, and insulation to find the most cost-effective path to 7 stars for your specific climate zone and orientation.

Step 2: Confirm Brick Type and Thermal Properties

Tell your assessor you’re specifying recycled clay bricks. The assessor will use the thermal properties of dense clay brickwork in their model. If you’re using The Brick Pit’s Combo or Face Grade recycled bricks for a double brick wall, those dense fired clay properties apply directly.

Step 3: Pair Thermal Mass with Correct Orientation

Thermal mass works best when paired with good passive design. For Australian homes:

• Place high-thermal-mass walls (brick) on north and west elevations to absorb and buffer afternoon sun
• Ensure adequate eave shading over north-facing glazing to prevent summer overheating
• Use reflective foil insulation in the roof space to manage radiant heat gain

Step 4: Consider a Double Brick Wall Configuration

Where budget allows, double brick construction using recycled clay bricks provides superior thermal mass on both sides of the wall cavity. Energy assessors consistently rate double brick as one of the most effective passive design strategies in Climate Zones 4–6 (southern Australia).

Step 5: Document Brick Grade and Source for Green Star or BASIX Credits

If your project is targeting Green Star or BASIX water/energy credits for material sustainability, ask The Brick Pit for documentation confirming the recycled origin and Australian sourcing of your bricks. This supports your assessor’s or certifier’s documentation requirements.

See also: our guide on how recycled bricks support Green Building certification and eco-friendly construction for more on the Green Star process.

Real Project: SBRC at the University of Wollongong

One of the most compelling demonstrations of recycled bricks in a high-performance sustainable building is the Sustainable Buildings Research Centre (SBRC) at the University of Wollongong, a project that supplied recycled bricks through The Brick Pit.

The SBRC became the first building in Australia to receive:

• 6 Star Green Star Design and As-Built certification
• Living Building Challenge certification (one of only a handful of buildings worldwide to achieve this at the time)
  

The building’s design combined passive solar principles, high-thermal-mass materials including recycled brickwork, and sophisticated energy modelling achieving a net-positive energy outcome. It stands as a proof point that recycled bricks are not just aesthetically appealing but are a credible high-performance material for the most demanding sustainability benchmarks.

Frequently Asked Questions

Q: Do recycled bricks help me meet the NCC 7-star energy rating requirement?

 A: Yes. Recycled clay bricks are a high-thermal-mass material that NatHERS assessment software models as reducing heating and cooling loads, the primary measure of the 7-star standard. In correctly oriented homes, recycled brick walls can contribute meaningfully to reaching or exceeding 7 stars.

Q: Are recycled bricks recognised under BASIX in NSW?

 A: Yes. The thermal mass properties of dense recycled clay bricks are recognised in BASIX’s thermal comfort assessment. Recycled bricks may also contribute to BASIX’s materials sustainability considerations.

Q: Can I use recycled bricks for a double brick wall that meets Australian Standards?

 A: Yes, provided the bricks are structurally graded. The Brick Pit’s Face Grade and Combo Grade bricks are individually inspected and comply with AS 3700. Always confirm the grade with your supplier and advise your certifier.

Q: Do recycled bricks count toward Green Star credits?

A: Yes. Recycled and reused materials are recognised in the Green Building Council of Australia’s Green Star rating system under materials credits. The Brick Pit can provide sourcing documentation to support your Green Star submission.

Q: How much CO₂ do recycled bricks save compared to new bricks?

 A: Approximately 0.5 kg CO₂ per brick avoided. For a home using 16,000 bricks, this is roughly 8 tonnes of CO₂ in avoided embodied emissions equivalent to around two years of average car emissions.

Q: Which climate zones benefit most from recycled brick thermal mass?

A: Climate Zones 4–7 (southern and south-eastern Australia – Sydney, Melbourne, Adelaide, Canberra, Perth and surrounds) benefit most from thermal mass strategies. In tropical Climate Zones 1–2 (Queensland’s far north, Darwin), thermal mass can trap unwanted heat and may need to be balanced with shading and ventilation design.

Q: Where is the 7-star requirement not yet in effect?

 A: Tasmania has deferred the 7-star provisions. The Northern Territory applies only to a 5-star requirement. In all other mainland states and the ACT, 7 stars is the mandatory minimum for new homes.

Summary: Why Recycled Bricks Are a Smart Choice for a 7-Star Home

Choosing recycled bricks for your 7-star build isn’t a compromise it’s an upgrade. You get the same thermal performance as new clay bricks, at a lower embodied carbon cost, at a lower purchase price, with a sustainability story that resonates with architects, certifiers, and increasingly, buyers.

Next Steps

If you’re planning a new build or major renovation and want to understand how to specify recycled bricks for NCC compliance, The Brick Pit’s team has been advising architects, builders, and homeowners since 1975. We can provide:

• Brick grade documentation for certifiers and energy assessors
• Advice on suitable brick types for structural vs feature wall applications
• Custom feature blends to match existing heritage brickwork or achieve a specific aesthetic
• Australia-wide supply to NSW, VIC, QLD, SA, WA, ACT, and New Zealand

External References

Australian Building Codes Board — NCC 2022 Energy Efficiency Provisions 

NatHERS Official FAQs — 7-Star Requirements