A simple guide for WA homes looking to get solar right the first time
One of the most common questions we get at Solar You is:
“How big should my solar system be?”
Great question — and the answer depends on a few key things, like your power usage, your roof space, and your future plans (think EVs or batteries).
Let’s break it down in a way that actually makes sense.
⚡️ How much power do you use?
Start with your electricity bill — it shows your average daily usage in kilowatt-hours (kWh). Here’s a rough guide:
| Daily Usage (kWh) | Suggested System Size |
|---|---|
| 10–15 kWh | 3–4 kW system |
| 15–25 kWh | 5–6.6 kW system |
| 25–35+ kWh | 8–10+ kW system |
👉 Most WA homes go for a 6.6kW system, which is a sweet spot for price and output — and the largest you can install and still get the full STC rebate without export limits (in most cases).
🏡 Are you home during the day?
Solar works best when you can use the power while the sun’s out.
- Home during the day? A standard system may be enough to slash your bill.
- At work all day? Consider going a bit bigger or adding a battery later to catch and store that daytime power.
🚗 Planning for an EV or battery?
If you’re thinking long-term:
- Getting an electric car? Go bigger. Charging an EV adds around 10–15 kWh per day
- Want battery storage later? Oversizing your solar system now gives you more energy to store and use at night
✅ Good news: We can install a battery-ready system today, even if you’re not buying the battery just yet.
📐 What about your roof space?
- A 6.6kW system usually needs 25–30 m² of roof space
- Bigger systems need more — or higher-efficiency panels if space is tight
- We’ll check shading, orientation, and roof angle to maximise production
💵 What’s the payback period?
The bigger your system, the more energy you can produce — but also the higher the upfront cost.
In WA, a well-sized system typically pays for itself in 3–5 years, and then it’s pure savings for 20+ years after that.
✅ The smart way to size your solar system
Ask yourself:
- How much power do I use now?
- Do I want to future-proof for an EV or battery?
- Can I shift usage to the daytime?
- What fits on my roof?
Still need help deciding? We can review your power bills, inspect your roof design, and model different system sizes using real Perth sunlight data. That way, you know exactly what your investment will produce and how quickly it’ll pay off. So get in touch now for advice and pricing, with no-obligations or pushy sales tactics.
