Free Solar Software Australia: What Adelaide Homeowners Can Use to Check Their Rooftop Solar Design
There are several free solar software tools available to Australian homeowners that let you estimate system size, model energy production, and get a rough sense of what solar panels might generate on your roof. These tools are useful for getting oriented before you talk to an installer — but they have real limitations that are worth understanding before you rely on them.
This guide covers what free solar software tools are actually available in Australia, what they can tell you, and where they fall short. It also covers what a professional solar design from a CEC-accredited installer like SBSE includes that free tools cannot produce.
At Sunbeam Solar and Electrical Solutions (SBSE), we are based in Dulwich, Adelaide. We have completed over 2,200 rooftop solar installations across Adelaide and Melbourne. Our SA-licensed electricians use professional solar design software to produce every proposal — not free tools.
What Free Solar Software Can Do for Adelaide Homeowners
Free solar software tools available in Australia are primarily solar system sizing calculators and basic energy production estimators. They are useful for homeowners who want to understand roughly what size system they need before requesting quotes.
Free solar system sizing and energy production calculators
The most commonly used free solar tools in Australia include:
- SunSPOT (CSIRO) — A free solar panel design and savings calculator developed using CSIRO Bureau of Meteorology data. Enter your postcode, roof orientation, and monthly bill and it estimates system size, annual energy production, and payback period. Useful for a starting point.
- Clean Energy Regulator STC Calculator — Calculates the approximate STC rebate value for any system size and postcode in Australia. Useful for checking whether a quoted rebate figure is in the right range.
- Your retailer's online calculator — AGL, Origin, and Powershop all offer basic solar savings estimators. These use your bill data and postcode to estimate savings from a standard system size.
These free tools are reasonable for getting a ballpark figure. They are not a substitute for a site-specific solar panel design that accounts for your actual roof dimensions, shading, and orientation.
Free Solar Panel Design Software: What It Can and Cannot Do
Basic free solar panel design software lets you map solar panels onto a roof using satellite imagery and estimate annual energy production. OpenSolar offers a free plan that includes rooftop solar panel layout tools and basic system design functionality.
What free solar panel design software covers
- Rooftop solar panel placement on satellite roof imagery
- Basic shading analysis
- Annual energy production estimate in kWh
- Simple system size recommendation based on consumption
What free solar software cannot do reliably
- Accurate shading analysis for Adelaide's specific sun angles — especially for roofs with chimneys, parapets, or nearby trees
- Three-phase supply assessment for larger kW systems
- Battery compatibility checking across specific inverter and solar battery brands
- SA-specific rebate eligibility calculations (STC zone, SA Home Battery Scheme)
- Payback period calculations using your actual tariff and consumption data
- Network operator export limit checks for systems above 5kW in SA
For a full breakdown of what a professionally designed on-grid residential rooftop solar system involves, see our guide to on-grid residential solar PV systems in Australia.
Solar System Design Software Used by Professional Australian Solar Businesses
Professional solar businesses — CEC-accredited installers and solar retailers — use paid solar design software that goes well beyond what free tools offer. The main platforms used by Australian solar businesses include Aurora Solar, PVSell, and SolarEdge Designer.
What professional solar design software includes that free versions do not
- High-resolution LIDAR shading analysis — not satellite approximation
- Irradiance modelling from Bureau of Meteorology data specific to your postcode
- Accurate annual energy production forecasts accounting for panel degradation over 25 years
- Full electrical design for SA network operator approval submissions
- Battery storage integration: capacity modelling across Tesla Powerwall, Sungrow, Fox ESS, and Growatt
- Detailed payback and ROI calculations using your actual electricity tariff and consumption
When SBSE produces a proposal, it uses professional solar design software. Every design is reviewed by the same SA-licensed electrician who will carry out the installation. No subcontractors. This is what you're paying for when you commission a professional solar business versus using a free tool yourself.
Rooftop Solar Panel System Size: How Free Tools Calculate It
Free solar software uses a simplified formula for system size: take your annual consumption in kWh, divide by 365 (days), divide by your location's average peak sun hours, and apply an efficiency factor. For Adelaide, that's roughly 5.1 peak sun hours per day and an 80% efficiency rate.
A typical Adelaide home using 6,000 kWh per year would calculate to approximately 4.1kW of solar panels as a minimum. Most installers recommend oversizing to 6.6kW to maximise export and accommodate future load growth (EV, air conditioning, pool pump).
Why system size calculations differ between free software and professional designs
- Free tools use a national average or postcode-level irradiance figure. Professional design software uses measured irradiance data specific to your suburb.
- Free tools assume ideal roof orientation. Professional system design accounts for your actual roof pitch, azimuth, and any tilt losses.
- Free tools ignore inter-row shading for larger rooftop solar arrays. Professional software models this and adjusts panel layout accordingly.
- Free tools don't account for inverter clipping on oversized systems. A 6.6kW solar panel array on a 5kW inverter clips generation at peak output — professional design software quantifies that loss.
These differences typically mean free tools overestimate annual energy production by 5–15% for Adelaide homes with anything other than a perfect north-facing unshaded roof.
Solar Battery Storage: What Free Software Can and Cannot Model
Most free solar software tools include a basic solar battery calculator that lets you enter a battery capacity in kWh and see how it would affect self-consumption and grid reliance. This is useful for understanding the concept but not for making purchase decisions.
What free solar battery calculators cover
- Self-consumption rate with and without battery storage
- Estimated percentage of overnight consumption covered by battery
- Basic payback period estimate using current grid tariff
What free battery tools miss
- Brand-specific battery performance data (Tesla Powerwall 3 vs Sungrow SBR100 vs Fox ESS ECS have different round-trip efficiency rates)
- VPP (Virtual Power Plant) revenue modelling for SA participants
- SA Home Battery Scheme loan eligibility and impact on payback period
- Inverter compatibility with specific solar battery brands
Battery payback in Adelaide without rebates runs 8–12 years. With the SA Home Battery Scheme, which has offered loans up to $10,000 in past rounds, payback can reduce to 5–7 years. Current rebate status: solar battery subsidy in Adelaide for 2024/2025.
If you have existing solar and are considering adding battery storage, free tools cannot assess inverter compatibility. Our guide to adding a battery to existing solar in Adelaide covers what a compatibility check involves.
Solar Battery Brands SBSE Installs: System Design Comparison
Free solar software tools don't carry brand-specific battery data. Here are the solar battery systems SBSE installs, with the detail any professional proposal from us will include.
| Brand / Model | Usable Capacity | Chemistry | Best Application |
|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | Lithium NMC | Large homes, EV charging, VPP participation |
| Sungrow SBR100 | 9.6 kWh | Lithium LFP | Adding battery to existing rooftop solar in Adelaide |
| SigenStor (Sigenergy) | 10 kWh | Lithium LFP | New solar + battery combination systems |
| Fox ESS ECS Series | 10.24 kWh | Lithium LFP | High-capacity battery retrofit for upgraded systems |
| Growatt ARK Series | 10 kWh (stackable to 30 kWh) | Lithium LFP | High overnight loads, small commercial solar applications |
Energy Production Estimates: How to Read What Free Software Gives You
Free solar software typically expresses energy production as an annual kWh figure. For Adelaide, a 6.6kW system on a north-facing unshaded roof should generate approximately 9,500 kWh per year. A west-facing roof of the same size generates roughly 7,900–8,200 kWh per year.
When comparing energy production figures from free tools with those in a professional proposal, check the following:
- Performance ratio used — Free tools often use 80%. Professional system design software typically uses 75–78% for Adelaide to account for real-world losses.
- Degradation factored in — Solar panels degrade roughly 0.5% per year. A 25-year energy production estimate must account for this. Free tools often don't.
- Shading losses included — Even minor shading from a chimney can reduce total rooftop solar output by 10–20% without microinverters or optimisers. Free tools may not model this accurately.
If a free solar software tool gives you an energy production estimate that's 20% higher than a professional installer's proposal, the professional figure is almost certainly more accurate — ask them to show you the shading and losses breakdown.
Large Rooftop Solar System Design: 13kW and Above
Free solar software tools are generally adequate for sizing systems up to 10kW on simple residential rooftops. For larger systems — 13.2kW and above — professional system design software is required because of SA network operator export limit rules and the complexity of multi-string or microinverter layouts.
A 13.2kW rooftop solar system paired with 20kWh of battery storage is one of SBSE's most common configurations for high-consumption Adelaide homes. At current SA electricity prices, this offsets $3,500–$4,500 in annual grid costs. Free solar software tools cannot model this accurately. See our breakdown of 13.2kW solar with 20kWh battery for Australian homes.
If your property has an older rooftop solar system from 2012–2018 that needs replacing, free system design tools won't help with the inverter compatibility assessment. See our guide to legacy solar system replacement for Australian homes.
Frequently Asked Questions About Free Solar Software in Australia
Is free solar software accurate enough for a real Adelaide installation?
Free solar software is accurate enough to give you a rough system size and ballpark payback period — useful before you request professional quotes. It is not accurate enough to use as the basis for an installation. A CEC-accredited installer must conduct a site-specific assessment using professional solar design software before any system is installed in SA.
What is the best free solar software tool for Australian homeowners?
SunSPOT (developed using CSIRO and Bureau of Meteorology data) is the most reliable free solar software tool for Australian homeowners. Enter your postcode, roof orientation, and electricity consumption to get a system size estimate and basic energy production figure. It's a good starting point. It won't replace a professional proposal from a CEC-accredited solar business.
Can free solar software design a full rooftop solar system with battery storage?
Free tools like OpenSolar can produce a basic rooftop solar panel layout and include a solar battery in the system design. However, they don't carry brand-specific battery performance data, don't check inverter compatibility, and can't calculate SA Home Battery Scheme eligibility. A professional proposal from SBSE covers all of these. Cost: $6,500–$20,000 depending on system size and battery brand.
What do free solar software tools get wrong about Adelaide specifically?
Three main things: they use a generalised postcode irradiance figure rather than suburb-level data; they typically assume perfect north-facing unshaded rooftop solar conditions; and they don't account for SA network operator export limits on systems above 5kW single-phase. A professional system design from an Adelaide installer corrects all three.
Does SBSE offer a free solar system design for Adelaide homeowners?
Yes. SBSE provides a no-charge site visit and professionally designed solar proposal for Adelaide homeowners. Our SA-licensed electricians assess your roof, review your electricity bills, and produce a full system design with energy production estimates, payback period, and rebate calculations. No free software can match this. Call 1300 789 291 to arrange yours.
What solar panels does SBSE install in Adelaide?
We install Tindo Solar panels (Australian-made in Adelaide, 25-year product warranty) as well as other Tier 1 brands. Every solar panel specification is included in our written proposals — brand, model, efficiency rating, and warranty. We don't quote "Tier 1 panels" as a generic category without naming the product.
Get a Free Professional Rooftop Solar Design for Your Adelaide Home
Free solar software tools are a reasonable starting point. They're not a substitute for a site-specific rooftop solar panel design from a CEC-accredited installer who has physically assessed your roof, reviewed your bills, and priced your system against current SA rebates.
SBSE is a CEC-accredited installer based in Dulwich, Adelaide. Over 2,200 installations completed. All solar panel system design and installation is carried out by our own SA-licensed electricians. No subcontractors.
Call 1300 789 291 or visit www.sbse.com.au to request a free solar proposal.
Book A Free Demo
