What Size Solar System Do I Need? A Gold Coast Guide for Homes & Businesses
Too small and you keep paying the grid. Too big and you export cheap energy you'll never get paid much for. Here's how our Arundel-based solar team sizes solar panels on the Gold Coast and across South East Queensland, with a free calculator you can use right now.
Use the Sizing CalculatorGet a Free Site AssessmentQuick answer: On the Gold Coast, each 1 kW of solar panels produces around 4 kWh of energy per day on average across the year. To size your system, divide your average daily electricity use (kWh) by 4. A typical Gold Coast household using 20 kWh a day suits a 6.6 kW to 10 kW system, while a business using 400 kWh during daylight hours suits roughly 100 kW. Your roof space, phase supply, Energex export limits and whether you add a battery will fine-tune the final size.
Why Getting Your Solar Size Right Matters in Queensland
A decade ago, the rule was simple: put as many panels on the roof as possible and get paid for every kilowatt-hour you sent back to the grid. That's no longer how solar pays off in South East Queensland.
Retail feed-in tariffs in SEQ are now usually just a few cents per kWh, while grid electricity costs many times that. You can compare current retailer offers on the government's Energy Made Easy website. On top of that, Energex limits how much your system can export, and many new connections now use dynamic export limits that change with network conditions.
The result? Every kWh you use yourself is worth far more than every kWh you export. The right-sized system matches your actual usage pattern, not just your roof size. If you're still weighing it up, read is solar power worth it for South East QLD homeowners?
How to Size a Solar System in 5 Steps
This is the same process our team follows during a site assessment, simplified so you can do a rough version at home.
Find your average daily energy use
Grab your last four electricity bills (a full year captures summer air-con and winter usage). Add up the total kWh and divide by 365. Most bills also show an "average daily usage" figure. Businesses can request 30-minute interval data from their retailer or smart meter provider.
Work out when you use it
Solar only produces during daylight. A household where everyone is out 8am–5pm might use only 30–40% of its energy in daylight hours. A café, workshop or cold-storage facility in Yatala or Molendinar might use 70–90%. The more daytime use, the more of your solar you'll consume directly, and the faster the payback.
Apply the Gold Coast solar yield
After real-world losses (heat, inverter efficiency, dust, cabling), a north-facing system on the Gold Coast averages roughly 4 kWh per installed kW per day. East/west roofs produce a little less overall but spread generation across the morning and afternoon. Our solar output calculator shows expected generation for different system sizes.
Example: 24 kWh/day ÷ 4 = a 6 kW minimum. Most homes then round up to a 6.6 kW or 10 kW system to allow for growth and battery charging.
Check your roof, phase supply and export limits
Each modern 440–475W panel takes up about 2 m², so allow roughly 5 m² of usable roof per kW. Single-phase homes are generally limited to around 10 kVA of inverter capacity, while three-phase properties can go larger. Energex's connection rules decide how much you can send back to the grid. We handle these applications for you.
Plan for the next 10 years, not just today
An electric vehicle adds roughly 6–10 kWh a day for typical Gold Coast driving, so if an EV is on the horizon, factor in an EV charger now. A heat-pump hot water system, pool pump, extension or new machinery will also change your load. It's usually cheaper to size up now than to add panels later, although we also offer solar system upgrades for existing systems.
Free Solar Size Calculator (Gold Coast & SEQ)
Enter a few details from your power bill for an instant estimate. It's a starting point; a site assessment confirms shading, roof orientation and network limits. You can also try our full recommended system size calculator or browse all our solar calculators.
Shown on your bill. Typical homes: 15–30 kWh. Small businesses: 50–300 kWh.
Recommended system size
Estimates use average South East Queensland solar yields and typical system losses. Actual results depend on shading, tilt, panel choice and Energex export approval. For an exact design, book a free assessment with our team.
Get My Exact DesignTypical Solar System Sizes for Gold Coast Homes
Based on the residential solar systems we design across the Gold Coast, Logan and Brisbane's southside, here's what usually works:
| Daily Usage | Typical Household | Recommended Solar | Approx. Panels | Battery? |
|---|---|---|---|---|
| 10–15 kWh | 1–2 people, apartment or townhouse, gas cooking | 5 – 6.6 kW | 12 – 15 | Optional |
| 15–25 kWh | Family of 3–4, air-con in summer, mostly out during the day | 6.6 – 10 kW | 15 – 23 | 5 – 10 kWh worthwhile |
| 25–40 kWh | Larger family, pool, home office, ducted air-con | 10 – 13 kW | 23 – 30 | 10 – 15 kWh recommended |
| 40 kWh+ | Acreage, EV charging, granny flat, all-electric home | 13 – 20 kW+ (often three-phase) | 30 – 45+ | 15 – 25 kWh+ |
Panel counts assume 440W panels. Single-phase homes are usually limited to around 10 kVA of inverter capacity under Energex rules; larger systems generally need three-phase power. Prefer a bundled option? See our solar and battery packages.
Sizing Commercial Solar: A Different Approach
For businesses, we don't start with the bill total. We start with your interval data, which shows your demand every 30 minutes, every day of the year. That tells us your daytime "base load": the energy your site uses consistently while the sun is up.
Commercial systems are usually sized so most of the solar output is consumed on-site, known as a high self-consumption ratio. That's what delivers the fastest payback, often 3–5 years for SEQ businesses with strong daytime loads. We also look at demand charges, which the right combination of solar and battery can reduce.
New to business solar? Start with our easy guide to getting solar for your business.
| System Size | Approx. Daily Generation | Suits | Roof Area |
|---|---|---|---|
| 30 – 50 kW | 120 – 200 kWh | Offices, gyms, auto workshops, medical centres | 180 – 300 m² |
| 100 kW | ~400 kWh | Supermarkets, schools, medium warehouses, cold storage | 600 – 700 m² |
| 250 kW – 1 MW | 1,000 – 4,000 kWh | Manufacturing, distribution centres, shopping centres, agriculture | 1,500 – 6,000 m² |
New in 2026: from 1 October 2026, the Small-scale Renewable Energy Scheme expanded from systems up to 100 kW to systems up to 1 MW. According to the Clean Energy Regulator, mid-scale systems between 100 kW and 1 MW can now receive upfront STC discounts, which changes the sizing maths for many larger Gold Coast businesses. Flexible solar finance options are also available.
Panels, Inverter & Battery: Sizing Them Together
Why a 6.6 kW system has a 5 kW inverter
Clean Energy Council guidelines allow your panel capacity to exceed your inverter rating by up to 33%. Because panels rarely hit full rated output in real conditions, slightly "oversizing" the panels keeps your inverter running closer to its maximum for more of the day. That's why 6.6 kW of panels on a 5 kW inverter, or 13.3 kW on a 10 kW inverter, are such common Queensland combinations. Learn more about the different types of solar inverters.
How big should my battery be?
A good starting point is to cover your evening and overnight usage, typically 40–60% of a household's daily kWh. If you use 20 kWh a day and most of it after 4pm, a 10 kWh battery is a sensible fit. Your solar array also needs enough surplus to fill that battery on an average day, which is why battery homes usually need a larger solar system. Try our battery size calculator and check your eligibility for the federal battery rebate in Queensland.
Explore our battery storage options, including Sungrow, Sigenergy, Tesla Powerwall 3 and BYD.
Common sizing mistakes we fix
- ✕Sizing to the roof instead of the usage, then exporting most of the energy for very little return
- ✕Undersizing to save upfront, then needing a costly second system when an EV arrives
- ✕Adding a battery to a system too small to charge it
- ✕Ignoring phase supply and finding out at the Energex application stage
- ✕Choosing cheap panels that degrade quickly in Queensland heat
What we do differently
- ✓Analyse your actual bills or smart-meter interval data
- ✓Shading and roof modelling before quoting
- ✓Handle all Energex connection and export applications
- ✓Tier-1 panels such as Trina Solar and REC
- ✓Licensed QLD electricians, locally based in Arundel. Read our customer reviews
Solar Sizing FAQs
What size solar system do I need for a 4-bedroom house on the Gold Coast?+
Most 4-bedroom Gold Coast homes use 20–30 kWh per day, which suits a 10 kW solar system (around 23 panels). If you have a pool, ducted air-conditioning or plan to add a battery or EV, a 13 kW system on three-phase power is often the better fit.
How much power does a 6.6 kW solar system produce on the Gold Coast?+
A well-installed, north-facing 6.6 kW system on the Gold Coast produces around 26 kWh per day on average, or roughly 9,500 kWh per year. Output is higher in spring and summer and lower in winter.
Is a 10 kW solar system worth it in Queensland?+
For households using 20 kWh or more a day, or anyone planning a battery or EV, a 10 kW system is usually worth it. The extra panels cost relatively little once installation is already happening. Use our payback calculator to check your numbers.
Can I install more solar than my inverter size?+
Yes. Clean Energy Council guidelines allow panel capacity up to 133% of the inverter rating. For example, 13.3 kW of panels can be paired with a 10 kW inverter.
What is the maximum solar system size for a single-phase home in SEQ?+
Single-phase homes in the Energex network are generally limited to around 10 kVA of inverter capacity, with export limits applied by Energex. Three-phase properties can typically install larger systems. We confirm your options during the connection application.
How much roof space do I need for solar?+
Allow about 5 m² of usable, unshaded roof per kilowatt. A 6.6 kW system needs roughly 33 m², and a 10 kW system needs around 50 m². Commercial systems need around 6–7 m² per kW once walkways and setbacks are included.
Should I get a bigger solar system if I plan to buy a battery later?+
Yes. A battery needs surplus solar to charge. If a battery is likely in the next few years, sizing your solar and choosing a battery-ready hybrid inverter now avoids replacing equipment later.
How do I size solar for my business?+
Commercial solar is sized using your 30-minute interval data so the system matches your daytime base load. The aim is high self-consumption, typically 80% or more of solar used on-site. Systems from 100 kW to 1 MW installed from 1 October 2026 may also be eligible for upfront STC discounts under the expanded Small-scale Renewable Energy Scheme.