What Size Solar System Do I Need?
Thinking about solar for your home or business in Western Australia? One of the biggest questions we get at COYCO is: “What size solar system do I need?” The answer depends on your electricity usage, available roof space, budget, and future energy plans. In this guide, we’ll walk you through the key factors WA homeowners should consider so you can make the best investment in solar power.
Key Factors That Affect Solar System Size
Sizing a solar system isn’t one-size-fits-all. COYCO’s licensed electricians in WA assess each property to match usage patterns with system design. Here are the major considerations:
1. Energy Usage
Review your electricity bills to see your average daily usage in kWh. Higher consumption requires larger solar systems. For example, a Perth family of four using 25 kWh/day may need a 6.6kW system, while a small household may only need 3–4kW.
2. Roof Space & Orientation
North-facing roofs capture the most sunlight in WA. Limited space or shading may affect the number of panels you can install, which influences total system size.
3. Budget & Rebates
The Clean Energy Council and WA Government offer incentives like Small-scale Technology Certificates (STCs) that reduce upfront costs. Larger systems have higher upfront costs but deliver more long-term savings.
4. Future Energy Needs
Planning on adding an EV or expanding your household? Oversizing your solar system slightly can future-proof your investment.
Step-by-Step Guide: Sizing Your Solar System
- Check your daily energy usage (kWh) on your electricity bill.
- Estimate how much of that usage you want solar to cover (self-consumption vs export).
- Match kWh demand to system size (e.g., 20 kWh/day ≈ 5kW system).
- Confirm available roof space for panels (approx. 1.7m² per panel).
- Factor in future usage (EVs, home extensions, appliances).
- Consult Coyco for professional system design and quote.
WA-Specific Considerations for Solar System Size
Western Australia offers some of the best solar potential in the country, but local conditions, tariffs, and lifestyle factors can all influence the ideal system size for your home. Before choosing a solar setup, it’s worth considering how these WA-specific elements affect performance and value.
- High solar exposure: Perth and much of regional WA enjoy 5–6 peak sun hours per day, which means smaller systems can often achieve great results. However, roof angle and shading from trees or neighbouring properties can still impact efficiency, so a professional site inspection is key.
- Energy usage patterns: Many WA households rely heavily on air conditioning in summer and may use electric hot water or pool pumps. If your energy use spikes during the day, sizing your system slightly larger can help offset higher demand without overspending.
- Tariffs and rebates: WA’s Synergy and Horizon Power offer solar buyback schemes, but rates vary depending on your region and usage times. It’s smart to size your system to maximise self-consumption — using your generated power directly — rather than relying on feed-in credits.
- Grid connection limits: In some regional or rural areas, network limits may restrict system size or inverter capacity. Your installer should check local grid requirements and obtain approval from Western Power or Horizon Power before installation.
- Future expansion: If you’re considering adding an electric vehicle, battery storage, or additional appliances later, plan ahead by installing an inverter with extra capacity. This futureproofs your system and saves on upgrade costs down the line.
By tailoring your solar system to local conditions and usage habits, you’ll get a setup that delivers maximum savings and long-term performance — perfectly suited for the WA lifestyle.
FAQs About Solar System Size in WA
Q1. What’s the most common solar system size in WA?
A 6.6kW system is the most popular for WA households, offering a good balance of cost and output.
Q2. Can I install a system larger than my inverter?
Yes. Oversizing panels up to 133% of inverter capacity is permitted under Clean Energy Council rules.
Q3. How much roof space do I need for a 6.6kW system?
About 32–36m², depending on panel wattage.
Ready to Size Your Solar System?
Choosing the right solar system size doesn’t have to be confusing. At COYCO, we provide tailored recommendations based on your energy use, budget, and long-term needs. Request a free solar assessment today and start your journey toward lower energy bills and a more sustainable WA home.
