If you’re building or renovating a home in Australia, you might be curious whether installing solar panels improves your NatHERS rating — especially as energy efficiency becomes more important under updated building codes. Let’s unpack what NatHERS measures, how solar fits in (now and in the future), and what you can do to improve your rating.
🏡 What Is the NatHERS Rating?
The Nationwide House Energy Rating Scheme (NatHERS) is a standardized system that assesses a home’s energy efficiency — originally focusing on how well the building’s design and materials keep it comfortable with less heating and cooling. It expresses this using a star rating between 0 and 10; higher stars mean better thermal performance and lower energy demand.
Traditionally, factors that influence this star rating include:
· Wall, roof and floor materials
· Insulation levels
· Window placement, size and glazing
· Building orientation
· Shading and ventilation
NatHERS modelling shows how much energy a house will need for heating and cooling — not electricity generation.
☀️ Do Solar Panels Directly Improve Your NatHERS Rating?
No — installing solar panels does not directly raise your official NatHERS star rating in the original thermal shell assessment. That’s because traditional NatHERS focuses mainly on passive energy efficiency of the building envelope — not how much electricity your home generates.
Solar panels reduce energy use and electricity bills, but they don’t change how much heating or cooling your home needs to stay comfortable — which is what NatHERS stars measure.
So while solar gives real financial and environmental benefits, your NatHERS star count usually won’t go up just because you add PV.
📊 What About the New “Whole of Home” NatHERS Rating?
Australia is updating NatHERS to include a “Whole of Home” rating that goes beyond just how the building performs thermally. This broader assessment takes into account:
· Heating & cooling loads
· Fixed appliances (like hot water systems)
· Solar energy generation
· Battery storage
Under this expanded system, on-site solar can be counted as energy generated, which subtracts from your household’s total energy use. Homes with PV (and storage) can potentially score better in this more complete performance measure — especially if the solar system offsets a large portion of your consumption.
This Whole of Home score is separate from the classic 0–10 star thermal rating, and is typically expressed on a 0–100 overall energy efficiency scale. A score of 100+ can indicate a home that generates more energy than it uses, which is a pathway toward net-zero energy.
📉 Why Solar Helps Your Overall Energy Efficiency
Even though solar doesn’t directly raise the traditional NatHERS star count, it still improves your overall energy performance in meaningful ways:
📌 Reduces Grid Dependency
Solar panels generate electricity during the day, cutting down how much grid energy your home needs — especially if you run appliances while the sun is shining. This contributes to a lower net annual energy use.
📌 Lowers Electricity Bills
Generating your own energy reduces what you buy from retailers — a financial benefit that’s closely tied to your living costs even if NatHERS stars stay the same.
📌 Adds Market Value
Homes with solar often fetch higher prices and greater buyer appeal. Research shows homes with solar systems are valued around 2.7 % higher, and properties with higher estimated energy efficiency (NatHERS stars) can see even more uplift.
📌 Supports Net-Zero Goals
For buyers and investors increasingly focused on sustainability, solar plus good insulation and passive design is a compelling combination, even if energy generation isn’t fully counted in the traditional star rating yet.
🔧 How to Improve Your NatHERS Rating (Thermal)
To lift your true NatHERS star rating — which measures comfort and thermal performance — focus on the building itself:
✔ Increase insulation in walls, roof and floors ✔ Optimise window placement, shading and glazing performance ✔ Minimise air leakage with sealing and good detailing ✔ Use materials with high thermal mass where appropriate ✔ Design for your climate (orientation and natural ventilation)
These changes directly reduce heating and cooling loads — the main drivers of the star rating — and give you the biggest boost per design dollar spent.
📌 FAQs — Solar & NatHERS
Q: Can solar help me meet building code requirements? Yes — solar can help in the Whole of Home energy budget and net energy targets even if it doesn’t raise the traditional star rating.
Q: Is solar counted in new NatHERS certificates? Under the expanded Whole of Home rating, onsite generation like solar can be included in overall performance measures.
Q: Should I install solar before or after a NatHERS assessment? For thermal stars, focus on building design first. For Whole of Home or energy budget compliance, including solar and batteries during planning helps provide a clearer picture of future performance.
Q: Do solar panels make my home more valuable? Yes — solar can increase property value and energy appeal, independent of the NatHERS star count.
🌱 Conclusion
Installing solar panels by itself won’t directly improve the traditional NatHERS star rating because that system focuses on how well your home keeps warm or cool without relying on heating/cooling systems.
However, solar does improve your overall energy efficiency, reduce bills, and contribute to broader performance measures, especially under the newer Whole of Home rating framework that includes generation and storage.
For the best results: ✔ Optimise your building’s thermal performance first. ✔ Combine good passive design with solar and batteries to boost your overall home energy performance. ✔ Use solar strategically to reduce net energy use and future costs.
Want a personalised energy efficiency and solar plan for your home? Arise Solar can help you maximise your comfort, ratings, and savings — contact us for a tailored assessment!