Achieving a 7-star energy rating for your existing Australian home in 2026 is a strategic investment that delivers substantial long-term savings and improved comfort. The process typically begins with a comprehensive NatHERS assessment, followed by targeted upgrades to insulation, windows, and major appliances like hot water systems and heating/cooling. With federal and state rebates available, homeowners can reduce upfront costs, making this a financially sound decision.
Australia’s building standards are evolving, with the National Construction Code (NCC) 2022 now mandating a minimum 7-star NatHERS thermal rating for new homes across most states and territories, up from the previous 6-star minimum. While this applies to new builds, the principles for achieving a higher rating are equally relevant for existing properties seeking to improve their energy performance. A 7-star home can reduce heating and cooling energy demand by up to 25% compared to a 6-star home, translating into tangible bill reductions.
Energy Assessment: Your Starting Point to 7 Stars
The first critical step is a professional energy assessment, specifically a NatHERS (Nationwide House Energy Rating Scheme) assessment. This evaluates your home’s thermal performance – how well it retains heat in winter and stays cool in summer – using accredited software. From mid-2026, the Albanese Government is investing to expand NatHERS more widely to existing homes, providing ratings and information on upgrades.
A NatHERS assessor will analyse your home’s design, orientation, construction materials, window types, and existing insulation levels. They then provide a star rating from 0 to 10, along with a detailed report outlining recommended improvements to reach a higher star rating.
Average NatHERS assessment costs for an existing Australian home in 2026 typically range from $300 to $600, with a median around $420. Costs can vary by state:
| State | Average NatHERS Assessment Cost (2026) |
|---|---|
| NSW | $350 – $600 |
| VIC | $300 – $550 |
| QLD | $300 – $500 |
| SA | $320 – $550 |
| WA | $350 – $600 |
| TAS | $320 – $550 |
| ACT | $350 – $600 |
| NT | $350 – $650 |
This assessment is crucial as it prioritises upgrades based on your home’s specific needs and climate zone, ensuring your investment is effective.
Key Upgrades for a 7-Star Energy Rating
To significantly improve your home’s energy rating, focus on these core areas:
1. Enhanced Insulation
Insulation is paramount for thermal performance. Upgrading or installing insulation in your ceiling, walls, and underfloor is often the most impactful step. For most Australian homes, aiming for R3.5 to R5.0 in ceilings and R1.5 to R2.5 in walls is recommended.
“Around 70 per cent of Australia’s 11 million existing homes were built before the introduction of minimum energy efficiency standards, with an estimated average energy rating of below 3 stars. Even improving a home from 3 to 5 stars could reduce the energy needed for heating and cooling by around 40 per cent with a corresponding reduction in costs and emissions.”
| Insulation Type | Typical Material Cost (per m²) | Typical Installed Cost (per m²) | Key Benefits |
|---|---|---|---|
| Glass Wool Batts | $5 – $10 | $12 – $35 (ceiling) | Cost-effective, good thermal performance |
| Polyester Batts | $8 – $14 | $12 – $35 (ceiling) | Hypoallergenic, made from recycled materials |
| Reflective Foil | $7 – $16 | $9 – $24 (Canberra) | Excellent for radiant heat reflection |
| Spray Foam | N/A (installed cost quoted) | $30 – $80 | Superior air sealing, high R-value, moisture resistance |
For a standard 3-bedroom home, expect costs for professional installation to be:
- Ceiling Insulation: $800 – $2,500
- Wall Insulation: $1,500 – $4,000
- Underfloor Insulation: $1,325 – $3,525
Victoria’s Victorian Energy Upgrades (VEU) program is set to introduce insulation discounts from early 2026, specifically for ceiling insulation, which could halve typical installation costs for eligible households. In the ACT, residents can receive up to $4,600 to help with the upfront costs of installing ceiling insulation through the Sustainable Household Scheme.
For more detailed information, see our guide: Slash Your Winter Bills by Up To $800: Best Home Insulation Upgrades & 2026 State Rebates
2. High-Performance Windows & Glazing
Windows are a major source of heat loss and gain. Upgrading to double glazing or low-emissivity (low-E) glass can significantly improve your home’s thermal envelope. Double-glazed windows feature two panes of glass with an airtight gap, reducing heat transfer.
| Frame Material | Average Installed Cost (per m²) |
|---|---|
| Aluminium | $300 – $1,250 |
| uPVC | $300 – $500 |
| Timber | $600 – $1,500 |
Individual installed windows can range from $600 to $2,000+ depending on size and style. Retrofitting double glazing into existing, structurally sound timber frames can cost $1,200 – $2,800 per window in Melbourne.
3. Draught Proofing & Sealing
Often overlooked, sealing gaps and cracks is a cost-effective way to prevent unwanted air leakage. Draught proofing around doors, windows, exhaust fans, and other penetrations can reduce energy waste. Professional draught proofing for the perimeter of a door can cost between $50 - $109 (excl. GST). A comprehensive assessment from a specialist can identify all leakage points.
4. Efficient Hot Water Systems
Hot water accounts for a significant portion of household energy use. Switching from an electric storage or gas system to a heat pump hot water system is a highly effective upgrade.
Heat pump hot water systems typically cost $3,500 – $7,000 for supply and basic installation, but federal Small-scale Technology Certificates (STCs) and state rebates can significantly reduce this. Nationally, the average installed cost in April 2026, including federal STCs, was $4,527. With state rebates in Victoria or NSW, the out-of-pocket expense can drop to between $2,667 and $4,073.
Popular models include the Rheem Ambiheat, Sanden Eco Plus, and Stiebel Eltron WWK. Running costs for a heat pump system are estimated at $150-$300 per year, roughly a third of an old electric storage tank.
For more details, consult our guide: Heat Pump Hot Water Australia 2026: Slash Bills by $900+ with Rebates
5. High-Efficiency Heating & Cooling
Older, inefficient heating and cooling systems are major energy hogs. Upgrading to a modern reverse cycle air conditioner provides both efficient heating and cooling from a single unit.
| System Type | Typical Unit Cost (excl. install) | Typical Installed Cost |
|---|---|---|
| Split System | $600 – $2,500 | $1,400 – $4,800 |
| Multi-Head Split | N/A | $4,200 – $8,000 |
| Ducted System | N/A | $8,000 – $17,000 |
Brands such as Mitsubishi, Hisense, and Kogan SmarterHome offer a range of energy-efficient reverse cycle models. In the ACT, residents can receive up to $3,000 to upgrade from ducted gas heating to reverse-cycle air conditioning.
6. Solar PV and Home Batteries
While solar PV and home batteries don’t directly impact your NatHERS thermal rating, they significantly reduce your home’s overall energy consumption from the grid, contributing to the Whole-of-Home rating introduced in NCC 2022. This rating, a score out of 100, accounts for fixed appliances like heating, cooling, hot water, and lighting, plus on-site energy generation. New homes must achieve at least 60.
Federal incentives like the Small-scale Renewable Energy Scheme (STCs) provide an upfront discount on solar panel installations. However, the deeming period for STCs dropped on January 1, 2026, resulting in a 15-20% reduction in the upfront discount for new solar panels compared to the previous year. The Cheaper Home Batteries Program, expanded from May 1, 2026, offers a discount of around 30% on the upfront cost of installing small-scale battery systems (5 kWh to 100 kWh), available for batteries connected to new or existing solar PV.
Explore financing options for these systems: Best Solar Panel & Home Battery Financing Options in Australia 2026: Loans, PPAs & Green Mortgages Explained
Government Rebates and Incentives (2026)
Beyond federal STCs and battery rebates, state and territory governments offer various programs to support energy efficiency upgrades:
- Victoria: The Victorian Energy Upgrades (VEU) program provides discounts and special offers on selected energy-saving products and services, including heat pumps and, from October 2026, ceiling insulation. Solar Victoria also offers rebates for solar PV and hot water.
- New South Wales: The Energy Savings Scheme (ESS) and Peak Demand Reduction Scheme (PDRS) incentivise energy-saving activities.
- Queensland: Offers Battery Support schemes.
- South Australia: The Retailer Energy Productivity Scheme (REPS) and Virtual Power Plant (VPP) incentives are in place.
- ACT: The Sustainable Household Scheme provides interest-free loans for energy-efficient upgrades, including assessments, insulation (up to $4,600 for ceiling), and heating/cooling (up to $3,000 for reverse cycle). The Access to Electric Program can even cover the full cost of gas-to-electric appliance upgrades and ceiling insulation for eligible residents.
- Tasmania & Western Australia: Offer territory-specific schemes for energy efficiency.
Always check your specific state or territory government energy website for the most current eligibility criteria and rebate amounts.
Estimated Costs and Savings for a 7-Star Retrofit
The total cost to upgrade an existing home from a low star rating (e.g., 2-3 stars) to a 7-star rating can vary significantly based on the home’s original condition, size, and the extent of upgrades required. A comprehensive retrofit could range from $15,000 to $40,000+ for a typical 3-4 bedroom home, depending on the combination of interventions.
- Assessment: $300 – $600
- Insulation (Ceiling, Walls, Underfloor): $4,000 – $10,000 (total, depending on coverage and R-value)
- Draught Proofing: $500 – $2,000 (for a thorough job)
- Double Glazing (partial/full replacement): $8,000 – $25,000+ (depending on number of windows and frame material)
- Heat Pump Hot Water System: $2,600 – $5,000 (after rebates)
- Efficient Heating/Cooling (Reverse Cycle Split Systems): $1,500 – $5,000 per unit (installed, depending on size/brand)
These investments, combined with federal and state rebates, can lead to substantial annual savings on energy bills. Most Australian households use between 5,500 and 9,000 kWh per year. By reducing heating and cooling demand by up to 25% (moving from 6 to 7 stars), and adding highly efficient appliances, annual electricity bill savings of $500 to over $1,000 are achievable, with even greater savings for homes currently below 6 stars.
The Certification Process
Once upgrades are complete, you can engage a NatHERS accredited assessor to conduct a final assessment. They will update the energy model with the improvements made and issue a new NatHERS certificate reflecting your home’s enhanced star rating. This official certification can add significant value to your property and provide peace of mind regarding ongoing energy costs.
Bottom Line
Upgrading your existing Australian home to a 7-star energy rating in 2026 is a highly effective strategy for long-term financial savings and improved living comfort. Begin with a professional NatHERS assessment to create a tailored action plan. Prioritise major thermal envelope improvements like insulation and high-performance windows, then focus on energy-efficient hot water and heating/cooling systems. Leverage the available federal and state government rebates to offset upfront costs. This holistic approach not only reduces your carbon footprint but also significantly enhances your home’s value and resilience against rising energy prices. The investment now will deliver consistent returns for years to come.