Why Solar Panels Alone Won’t Help You Pass BASIX
- Sarah Campbell
- Nov 10, 2025
- 2 min read
When it comes to BASIX compliance in NSW, one of the most common misconceptions we hear is:
“If I’ve got solar panels, I’ll be fine.”
Unfortunately, that’s not quite true.
Solar panels are a great investment for reducing ongoing energy costs — but under BASIX, they sit in a completely different category to your thermal performance.
Let’s break it down.
The three parts of BASIX
BASIX (the Building Sustainability Index) assesses a home’s sustainability across three key areas:
1️⃣ Thermal performance – how well your home naturally maintains comfortable temperatures.
2️⃣ Energy use – how much energy your design will consume through appliances, heating, cooling, lighting, and solar generation.
3️⃣ Water use – how efficiently your home collects and uses water through fixtures, fittings, tanks, and reuse systems.
Most people focus heavily on the thermal component — the one that’s tied to your 7-Star NatHERS rating. But the energy and water sections are equally important. Each has its own targets that must be met for your BASIX certificate to be approved.
Why solar panels don’t boost your 7-Star rating
Your 7-Star rating is based purely on your home’s thermal performance — the design, insulation, glazing, orientation, and materials that determine how well it retains heat in winter and stays cool in summer.
Solar panels, on the other hand, are assessed under the energy section of BASIX. They can help you meet your energy consumption target, but they don’t affect your thermal score.
So, if your home design only reaches 6.3 stars, adding solar panels won’t push it up to 7. You’ll need to improve the building envelope — things like insulation, window performance, and shading — to get there.
The overlooked sections: water and energy
Even if your design nails the thermal target, BASIX still checks how your home performs in water and energy use.
For water, BASIX looks at:
Rainwater tanks and their connection points (toilets, laundry, irrigation).
Efficient fixtures and fittings (like low-flow taps and 4-star showerheads).
How much roof area collects into your tank.
For energy, it considers:
Appliance efficiency (ovens, cooktops, air conditioning, hot water systems).
Inclusion of solar systems or battery storage.
Lighting, ventilation, and even whether a clothesline is included (to offset dryer use).
All three sections must meet their targets for approval. If even one falls short, your BASIX certificate won’t pass.
How to avoid BASIX setbacks
The easiest way to stay compliant — and avoid redesigns or delays — is to consider all three BASIX components early in the design stage.
At Studio Terra, we help homeowners, builders, and architects identify opportunities across thermal, energy, and water performance from the outset. That means fewer surprises at submission time, smoother approvals, and smarter, more sustainable homes overall.
Need clarity on your BASIX assessment?
If you’re unsure whether your design meets the full BASIX requirements — or want to understand what’s really needed to hit your targets — we can help.
📞 Book a Clarity Call to discuss your project one-on-one.We’ll walk you through exactly what BASIX assesses and show you how to meet every target with confidence.
