South African solar customers are not buying a payback period. They are buying the ability to keep the lights on, the fridge running, and the business trading when the grid is down. That means the most important number in the proposal is not the internal rate of return, it is how many hours the system carries their load in an outage, and almost no proposal software calculates it.
Direct answer. The best solar proposal software in South Africa is whichever tool can state a backup runtime against a defined essential load. In practice that means inverter manufacturer tools for residential, and SurgePV or a hybrid model built on PVsyst or HOMER Pro output for commercial. Payback modelling matters, but it is the second question the customer asks, not the first.
TL;DR
- Lead with backup runtime against a named essential load, not with payback.
- Municipal tariffs differ substantially and many now include fixed and capacity charges that solar does not reduce.
- Model consecutive outage days. A system that works for one outage can fail on the second.
- Business customers can access renewable energy tax allowances, which changes the commercial case materially.
- State the essential load schedule explicitly so the customer knows what will not be backed up.
What South Africa Actually Changes About Proposal Software
Runtime is the headline number. The customer’s question is how long the system runs their essential load without the grid. Answering it requires an essential load schedule, a battery capacity, a usable depth of discharge, and an inverter continuous rating. A proposal that reports annual generation and a payback period without stating runtime has not answered the question that motivated the enquiry.
Consecutive outages break naive designs. A battery sized for one evening outage may not recover if the following day is cloudy and another outage follows. Modelling a worst-case sequence, rather than a typical day, is what separates a system that performs in a bad week from one that disappoints.
Municipal tariffs are not uniform and not all of it is avoidable. Tariffs differ significantly between municipalities and Eskom direct supply, and many include fixed monthly and capacity-based components that solar does not reduce. A savings model applied to the whole bill overstates the benefit. Model only the energy component the system actually displaces.
Business allowances change the case. South African tax provisions have allowed businesses to write off renewable energy assets on favourable terms. Where applicable, this materially improves the commercial case, and the current provisions should be confirmed rather than assumed.
Feed-in is secondary. Some municipalities compensate exported energy, many do so at modest rates, and registration requirements apply. Export is rarely the reason a South African system is bought, and it should not carry the proposal.
The Platforms Ranked for South Africa
| Platform | Best for | Backup runtime output | Municipal tariff modelling | Design output | Price per seat per year |
|---|---|---|---|---|---|
| Inverter manufacturer tools | Residential hybrid proposals | Native | Basic | Sizing only | Free with equipment |
| SurgePV | Commercial proposals plus design | Configurable | Configurable | Full, with DWG | $1,299 to $1,899 |
| HOMER Pro | Hybrid and off-grid commercial | Best in class | Manual | No | Licence-based |
| PVsyst plus spreadsheet | Bankable commercial cases | Manual | Manual | Yield only | ~$500 plus time |
| HelioScope | C&I layout and yield | No | No | Layout only | ~$1,188 |
| OpenSolar | Small residential volume | Basic | Configurable | Basic | $0 plus transaction fees |
| Aurora Solar | Larger commercial-facing teams | Configurable | Configurable | Good | $1,908 to $3,108 |
Inverter manufacturer tools dominate South African residential proposals for a good reason: they model their own hybrid equipment accurately and produce runtime figures directly. The caveat is that they size for one brand.
SurgePV covers the commercial case, producing hourly generation, the system design, the single-line diagram, and the customer document from one model. Technical detail in best solar design software in South Africa.
HOMER Pro is the rigorous option for hybrid commercial and off-grid sizing. See our HOMER Pro vs PVsyst comparison.
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What a South African Proposal Has to Contain
- Essential load schedule listing exactly which circuits are backed up and their draw.
- Backup runtime for the essential load, stated in hours at a defined depth of discharge.
- Consecutive outage scenario showing performance over a bad sequence, not just a typical day.
- System specification with array, inverter continuous and surge rating, and battery capacity.
- Generation estimate with the data source named.
- Tariff analysis against the specific municipality or Eskom tariff, separating the energy component from fixed and capacity charges.
- Non-backed-up circuits stated plainly, so the customer knows what will not work.
- Tax allowance position for business customers.
- SSEG registration and Certificate of Compliance included in the scope and timeline.
Item 7 prevents the most common South African complaint. A customer who did not realise the geyser, the pool pump, or the air conditioning was excluded discovers it during the first outage, and the installer gets the call.
Pricing in Rand
| Stack | USD per year | Approx. ZAR at 18.5 | Covers |
|---|---|---|---|
| Inverter vendor tools | Free with equipment | Free | Residential hybrid proposals |
| OpenSolar | $0 plus fees | Transaction-linked | Basic residential proposal |
| PVsyst | ~$500 | ~R9,250 | Yield, no proposal |
| SurgePV | $1,299 to $1,899 | ~R24,032 to R35,132 | Proposal plus design and SLD |
| Aurora | $1,908 to $3,108 | ~R35,298 to R57,498 | Proposal plus design |
Exchange rate is illustrative and the rand is volatile.
What Most South African Installers Get Wrong
They quote savings against the whole electricity bill.
Municipal bills increasingly include fixed monthly charges and capacity-based components that a solar system does not reduce, and in some tariffs those are a substantial share. A proposal that applies the solar offset to the total bill overstates the saving, sometimes by a lot, and the customer sees the real number on their first statement. Model only the energy component the system displaces, and show the fixed charges as unavoidable.
The second mistake is quoting runtime at full battery capacity. Usable capacity is lower than nameplate once depth of discharge limits are applied, and quoting the nameplate figure means the customer’s real runtime is shorter than promised on the day it matters most.
When Proposal Software Is Not the Constraint
Commercial and industrial enquiries in South Africa usually stall on engineering: whether an older industrial roof can carry the array, how a ground-mount will be founded, and what the construction documentation looks like.
Our solar rooftop detailed engineering design, solar ground mount design, and STAAD Pro report calculations services cover that work, and we deliver across African markets with DFI-acceptable documentation where financing requires it. See the sample design pack or talk to our team.
Conclusion
- Lead with runtime, not payback. It is the number the customer called about.
- Model only the avoidable part of the bill. Fixed and capacity charges do not go away, and pretending otherwise creates a complaint.
- State the non-backed-up circuits. The first outage is a bad time for the customer to learn what was excluded.
In this country series: solar software in South Africa, best solar design software in South Africa, shading analysis software in South Africa, Opensolar review. Tool deep dives: Pvsol review, Pvcase review.
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Disclosure and accuracy note
Commercial relationship. Heaven Designs and SurgePV are part of the same group. Treat our recommendation of SurgePV as a vendor making its own case, not an independent verdict. We have tried to describe every other product fairly, and to say plainly where a competitor is the better choice.
Pricing. All prices are indicative, compiled from public sources when this page was written. They vary by tier, region, contract term and exchange rate, and change without notice. Several vendors quote rather than publish, and some price in currencies other than the US dollar, so a converted figure moves with the exchange rate. Confirm current pricing with the vendor before you decide anything.
Trademarks and corrections. All product names and trademarks belong to their respective owners, and are used here for identification and comparison only. Their use does not imply affiliation with or endorsement by those companies. If anything here is out of date or wrong, tell us and we will correct it.
FAQ
What is the best solar proposal software in South Africa? Inverter manufacturer tools for residential, because they produce runtime figures natively, and SurgePV or a hybrid model built on PVsyst or HOMER Pro output for commercial work.
Why does backup runtime matter more than payback? Because supply interruption is what drives most South African solar purchases. Customers want to know how long the system carries their essential load, and payback is a secondary question.
How should municipal tariffs be modelled? Against the specific municipality or Eskom tariff, separating the energy component the system displaces from fixed monthly and capacity charges that it does not reduce.
What is an essential load schedule and why does it belong in the proposal? It lists which circuits the system backs up and what they draw. Stating it prevents the most common complaint, which is a customer discovering during an outage that a major appliance was excluded.
Do businesses get a tax benefit for solar in South Africa? Tax provisions have allowed businesses to write off renewable energy assets on favourable terms. Confirm the current provisions at the time of the project rather than carrying a remembered figure.
How much does solar proposal software cost in South Africa? From free with inverter manufacturer tools to roughly R57,000 per user per year at Aurora’s higher tiers. Cross-platform math is in our solar design software pricing breakdown.
What about the design software decision separately? Covered in best solar design software in South Africa.
