Most Sunny Design review searches come from installers who have already opened it, found it competent, and are trying to work out whether it can replace something they pay for. SMA Solar Technology has published this planning tool for years, and it has quietly become the reference free tool for one specific job: sizing strings and choosing an inverter against how an SMA inverter actually behaves. SMA’s own product page says it without hedging: “Sunny Design is free to use.” What most reviews miss is that there is also a paid tier, Sunny Design PRO, which SMA lists at 600 euro per year net. We have run Sunny Design alongside paid platforms across our own project pipeline at Heaven Green Energy, and the honest read is that it is narrower than SolarEdge Designer or Huawei SmartDesign in one direction and considerably wider in another.
Direct answer. SMA Sunny Design is free to use in the browser or on a tablet, with a paid PRO tier listed by SMA at 600 euro per year net and a one month trial. It is strongest on string sizing, inverter configuration and sector coupling into storage, heat pumps and e-mobility. It scores 30 of 50 on our bench. SMA’s documentation does not describe third party inverter support, and the tool is not positioned as a proposal or permit product.
This review evaluates Sunny Design as a stack decision, because that is what it really is. If you want the wider no cost field, our free solar design software comparison covers it. What follows is where Sunny Design beats tools you pay for, where it stops, and the reader for whom it is the correct primary tool.
What Sunny Design Is
Sunny Design is a free planning tool published by SMA Solar Technology AG, the German inverter manufacturer, and it runs in a browser or on an iPad or Android tablet. SMA describes the workflow as entering the required information and having the ideal system configuration available within a few minutes.
Its scope is wider than the phrase “design tool” suggests. Sunny Design plans grid connected PV with or without a battery storage system, off grid island systems and hybrid systems. It covers smart energy management, and it integrates e mobility for private homes. On SMA’s Sunny Design product page the tool is framed as planning of complete energy systems rather than laying out modules, and that framing is accurate.
Visual roof planning is included, and so is shading. SMA’s documentation lists calculation of the annual shading of the surfaces and of the PV modules, display of the percentage of module shading, and display of the shadow course for a selected point in time. That is more shading capability than a free manufacturer tool usually carries, though it is planning grade rather than survey grade, a distinction the next sections take seriously.
Two documented limits are worth knowing before you commit a workflow to it. SMA’s material states a maximum of 6 PV generators per sub project, with a warning when the maximum number of subsystems is exceeded, and it validates against a maximum grid connection load. Those are not arbitrary. They tell you the tool was scoped for residential and small commercial systems, not for a 40 sub array industrial roof.
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Book a free SurgePV demo → Compare pricingThe 5-Axis Review Bench
Every software review on this site scores a tool out of 50 on the same five axes. We call it the Heaven Green 5-Axis Review Bench, and the axes are published so the score can be argued with.
- Design and simulation depth. Roof accuracy, and whether the yield figure is a simulation or an estimate.
- Compliance and documentation output. The single line diagram, bill of quantities and plan set a permit office or a lender will accept.
- Proposal and sales workflow. Branded customer document, financing math, signature, handoff to a CRM.
- Price against value. What you pay against what you get, counting the tools you still have to buy alongside it.
- Support and onboarding. Documentation, training, response time, and how fast a new designer becomes productive.
| Axis | Score | Why |
|---|---|---|
| Design and simulation depth | 6 / 10 | Serious string sizing and sector coupled simulation, annual and instantaneous shading. No satellite 3D roof capture, no P90, SMA inverters only |
| Compliance and documentation | 4 / 10 | Detailed energy report and, on PRO, extended project documentation and time series export. No permit plan set, no stamped SLD |
| Proposal and sales workflow | 3 / 10 | A technical report, not a customer proposal. No branded document, no e-signature, no CRM |
| Price against value | 9 / 10 | The base tool is free with no seat limit, and the paid tier is 600 euro a year net, which is low for what it adds |
| Support and onboarding | 8 / 10 | A published user manual, a long running technical blog, and a tool most European installers were trained on |
| Total | 30 / 50 | An engineering tool that does not pretend to be a sales tool |
Thirty out of fifty is lower than SolarEdge Designer scored on this bench, and the reason is not quality. Sunny Design is a narrower product by choice. It concentrates almost everything into the engineering axis and spends nothing on the proposal and documentation axes, where Designer at least produces a branded customer document.
Verdict. If SMA inverters carry most of your jobs and your bottleneck is getting the string configuration and the sector coupled energy balance right, Sunny Design is the correct free tool and PRO is cheap for what it adds. If your bottleneck is producing a proposal a homeowner will sign or a drawing a permit office will stamp, neither published tier is scoped for that job and you will need a second tool.
Pricing
Sunny Design has two tiers and SMA publishes both, which is more transparency than most vendors on this site manage.
| Tier | Published price | What it adds |
|---|---|---|
| Sunny Design | Free to use, per SMA’s own product page | PV system design, visual roof planning with shading analysis, storage, off grid and hybrid, e-mobility for private homes |
| Sunny Design PRO | ”Price per year (net) 600 €” on SMA’s product page, one month free trial | Tariff management, consumption data and load profile analysis, extended project documentation, time series export, thermal components including heat pumps and CHP |
Two honest notes on that table. First, the 600 euro figure is stated net, so add your local VAT. Second, we found third party software directories describing Sunny Design PRO as free with registration. SMA’s own product page, checked on 2 August 2026, publishes a price per year of 600 euro net. Where a vendor’s own page and an aggregator disagree, we use the vendor’s page and tell you the disagreement exists. Confirm with SMA for your country before you budget, because SMA runs country specific sites and promotional access has existed in the past.
📘 Regulation note
Sunny Design validates against a maximum grid connection load and warns when it is exceeded. That check reflects European connection rules, not Indian DISCOM sanctioned load rules, so treat the warning as a prompt to verify locally rather than as compliance.
The cost that lands on your invoice regardless of tier is the second tool. Sunny Design produces an engineering report, not a proposal and not a permit drawing, so an installer who sells and submits needs a platform alongside it. Our solar design software pricing breakdown sets out what that costs across the market.
What Sunny Design Does Best
Two things, and both are unusual in the free tier.
String sizing against real inverter behaviour. This is the reason the tool has survived for as long as it has. Choosing an inverter is not a matter of matching kW to kWp. It is a question of whether the string voltage stays inside the MPPT window at the coldest record temperature and the hottest afternoon, whether the DC to AC ratio pushes the inverter into clipping often enough to matter, and whether the MPPT inputs are balanced across roof orientations. Sunny Design runs those checks against SMA’s own inverter data rather than a datasheet interpretation, and it tells you when a configuration is legal but poor rather than only when it is illegal. If you want the underlying concepts, our glossary covers MPPT, inverter clipping and string current mismatch.
Sector coupling that most rooftop tools do not attempt. Sunny Design plans PV with battery storage, off grid and hybrid systems, smart energy management and e-mobility, and PRO extends into thermal components such as heat pumps and combined heat and power. Almost no free rooftop design tool models a heat pump against a PV generation profile. For a European installer whose customers are electrifying heating and driving, that single capability is worth more than a prettier roof render. It is also increasingly relevant in India, where commercial customers running chillers and heat pumps face the same load matching problem.
The shading work also deserves credit, with a caveat. Annual shading calculated per surface and per module, a percentage of module shading, and a shadow course you can step through at a chosen time of day is more than a token feature. It is enough to catch a chimney or a neighbouring building that would otherwise wreck a string. What it is not is a surveyed shade model, which is a different claim entirely and one we make in the next section rather than here. Our shading loss glossary entry explains what the difference costs in kWh.
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Where Sunny Design Falls Short
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1
SMA inverters, and that is the point. SMA's own documentation does not state third party inverter support, and the tool's value comes from configuring against SMA hardware behaviour. Treat it as an SMA tool, because that is what it is.
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2
It is not a proposal tool. You get a detailed energy report with efficiency forecasts. You do not get a branded customer document, financing tables, an electronic signature or a CRM handoff. The sales half of the job happens somewhere else.
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3
No stamped permit output. SMA's published feature list, read on 2 August 2026, describes no drafted, dimensioned single line diagram and no plan set. PRO's extended project documentation is a better report, not a submission drawing.
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4
Structural limits on system size. A documented maximum of 6 PV generators per sub project, with warnings past that, means large multi array commercial and industrial roofs have to be split or moved to another tool.
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5
Shade input is drawn, not surveyed. SMA's documentation lists no LiDAR import and no drone photogrammetry. On a treed site or a dense urban block the shade model is only as good as the obstruction dimensions you typed in.
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6
No probabilistic yield. You get an expected annual figure, not the P50, P75 and P90 bands a project finance lender usually asks for, so expect to produce that number elsewhere.
⚠️ Watch out
Sunny Design's engineering credibility is exactly what makes its output a poor sales document. In our experience, handing a homeowner a technical energy report instead of a proposal loses deals to installers who send a clean one page quote. Use the numbers, rebuild the document.
Who Should Buy Sunny Design
- ✓ SMA inverters carry most of your jobs
- ✓ Your hard problem is string sizing and inverter selection
- ✓ Your customers are adding heat pumps, EV charging or storage
- ✓ You design off grid or hybrid systems, not only grid tied
- ✓ Someone else, or another tool, produces your customer proposal
- ✗ The document you send the customer is your bottleneck
- ✗ Inverter brand changes per project
- ✗ Your roofs need more than 6 PV generators per sub-project
- ✗ A lender asks you for P90 yield
- ✗ You need permit drawings from the same file
The reader for whom Sunny Design beats everything else, including SurgePV, is the technically led SMA installer or independent consultant whose deliverable is an engineering answer rather than a sale. A one or two person firm doing off grid, hybrid and sector coupled residential work in a market where SMA is the default inverter should use Sunny Design and pay for PRO if tariff modelling matters. Six hundred euro a year for load profile analysis and thermal component planning is cheap against any cloud platform, and a general purpose design tool will not model the heat pump at all.
Who Should Not
The obvious group is the volume residential sales operation. If your business is booked site visits and signed quotes, Sunny Design is the wrong centre of gravity. It will give you a defensible number and leave you to build the document that wins the job. Our best solar design software ranking covers the platforms built for that motion.
The less obvious group is the growing commercial installer who has been using Sunny Design happily on 5 to 30 kW rooftops. The 6 generator per sub project limit is where that story ends, and it ends abruptly. A 300 kW industrial roof with nine orientations and a mix of module types is not a Sunny Design project, and discovering that mid tender is expensive. If commercial work is coming, run a platform that scales alongside it now. Our commercial solar design software guide sets out what that chain looks like.
A third group worth naming: anyone whose market has moved to module level power electronics. Sunny Design is a string architecture tool at heart. If your standard answer to shade is an optimiser or a microinverter, read our SolarEdge Designer review instead, because that tool models the architecture natively.
Sunny Design vs SurgePV
Disclosure, stated plainly. Heaven Green Energy runs SurgePV on its own EPC work, and SurgePV is a sister product inside the Heaven Group. That is first hand operating experience and it is also a commercial interest. Both are true, so SurgePV’s weaknesses sit in the same table.
| Axis | SMA Sunny Design | SurgePV |
|---|---|---|
| Price | Free base tier. PRO listed at €600 per year net | $1,299 per user per year, 5-User Team plan |
| Hardware neutrality | SMA inverters | Multi vendor module and inverter database. Racking database is thinner than the module and inverter libraries |
| String sizing | Against SMA’s own inverter behaviour, the strongest thing in the tool | Automatic across any inverter, without one manufacturer’s internal rule set |
| Sector coupling | Storage, off grid, hybrid, e-mobility, and heat pumps and CHP on PRO | Storage modelled. No heat pump or CHP simulation |
| Roof capture | Visual roof planning, manual obstructions | Satellite plus AI 3D roof. No drone or LiDAR capture of its own |
| Shading | Annual shading per surface and per module, shadow course at a chosen time | 8,760-hour module level simulation |
| Yield reporting | Detailed energy report, expected annual figures | P50, P75 and P90 bands |
| System size limit | Max 6 PV generators per sub-project | No comparable documented cap |
| Single line diagram | ✗ | ✓ auto generated |
| Proposal and e-signature | ✗ technical report only | ✓ white label web proposal with e-signature |
| Structural stamping | ✗ | ✗ neither tool stamps drawings |
| Brand recognition | SMA, one of the oldest names in inverters | Thin, launched 2025, far fewer reference installs |
SurgePV’s side of that table is documented on its solar simulation software and solar proposals pages.
The honest summary: Sunny Design wins on sector coupling and on SMA specific string configuration, and it wins on price at both tiers. SurgePV wins on hardware neutrality, on documentation, on proposals and on lender facing yield. An SMA heavy engineering firm that occasionally needs a permit set can legitimately run both, and the combined cost is still lower than most single cloud platforms.
How Heaven Green Energy Uses This In Practice
We keep Sunny Design open for one job: sanity checking string configurations on hybrid and off grid work where the inverter is SMA. On a recent 15 kW hybrid installation for a farmhouse outside Rajkot with a diesel generator in the loop, the sizing that came out of our neutral tool and the sizing Sunny Design produced differed on how many modules could sit on one MPPT input at the winter minimum temperature. Sunny Design’s was the conservative number and it was the one we built, because it was applying SMA’s own operating envelope rather than a generic datasheet reading.
Everything after that leaves the tool. The stamped SLD, the bill of quantities, the structural check and the DISCOM net metering file are produced elsewhere. Drawings that need an engineering signature go through Heaven Designs rooftop detailed engineering, and on brand neutral jobs we check the string numbers against QBits Energy’s free string sizing calculator before committing to a layout. The customer facing proposal is built in a proposal tool, because in our experience handing a homeowner an engineering report costs deals.
For homeowners and businesses who arrived here comparing installers rather than software:
- Residential Solar: 1 to 10 kW rooftop systems with PM Surya Ghar subsidy handled for you.
- Commercial Solar: 10 to 100 kW with ROI modelling and accelerated depreciation planning.
- Industrial Solar EPC: 100 kW and above, turnkey.
- Solar Calculator: subsidy and 25 year savings in 60 seconds.
Independent market context on the European inverter market and on sector coupling is tracked by pv magazine and Mercom India. Indian rooftop rules sit with MNRE, and inverter conformity requirements under IS and IEC standards are published by the Bureau of Indian Standards.
Related Software Reviews
Same bench, same five axes, different tools.
- SolarEdge Designer Review
- Huawei FusionSolar Design Review
- Solar Monkey Review
- PV*SOL Review
- PVsyst Review
For the category view, start at the solar design software pillar or the 3D solar design software guide.
Frequently Asked Questions
Is Sunny Design free?
Yes. SMA states on its own product page that Sunny Design is free to use, and there is no seat limit or project cap on the base tier. It runs in a browser or on an iPad or Android tablet. There is a separate paid tier, Sunny Design PRO, which SMA lists at 600 euro per year net with a one month free trial. The base tool remains free whether or not you take PRO.
What does Sunny Design PRO add over the free version?
According to SMA’s own comparison, PRO adds tariff management, consumption data and load profile analysis, extended project documentation, and time series export. It also extends planning into thermal components such as heat pumps and combined heat and power plants, which the free tier does not model. If your work involves electrified heating or time of use tariffs, that is what the 600 euro per year buys.
Does Sunny Design work with non SMA inverters?
SMA’s documentation does not state third party inverter support, and the tool’s value comes from configuring against SMA’s own inverter behaviour. Treat Sunny Design as an SMA planning tool. If your inverter brand changes from job to job, you need a brand neutral platform, because the configuration work Sunny Design does best does not carry across to another manufacturer’s hardware.
Can Sunny Design do shading analysis?
Yes, at planning grade. SMA’s documentation lists calculation of annual shading of the surfaces and of the PV modules, display of the percentage of module shading, and display of the shadow course for a selected point in time. What it does not offer is surveyed shade input. SMA’s documentation lists no LiDAR import and no drone photogrammetry, so the model is only as accurate as the obstruction dimensions you enter.
Is there a system size limit in Sunny Design?
Yes. SMA’s documentation states a maximum of 6 PV generators per sub project and warns when the maximum number of subsystems is exceeded. It also validates against a maximum grid connection load. Those limits make it clear the tool was scoped for residential and small commercial systems. A large multi array industrial roof has to be split across sub projects or moved to a different platform.
Does Sunny Design produce a customer proposal?
Not in the sense a salesperson means. It produces a detailed energy report with key figures and efficiency forecasts, which is an engineering document rather than a sales document. SMA’s feature list describes no branded customer proposal, financing table, electronic signature or CRM handoff. Installers who use Sunny Design for the numbers almost always rebuild the customer facing document in a separate proposal tool.
Sunny Design or SolarEdge Designer, which is better?
They solve different problems. Sunny Design is stronger on string sizing, off grid and hybrid systems, and sector coupling into heat pumps and e-mobility. SolarEdge Designer is stronger on satellite roof capture, module level shade modelling and producing a branded customer proposal, and it carries a published DNV GL validation against PVsyst. Pick the one that matches your inverter, since neither works with the other’s hardware.
Is Sunny Design good enough for commercial projects?
For small commercial rooftop on SMA hardware, yes. Beyond that the documented cap of 6 PV generators per sub project becomes a real constraint, and the tool gives an expected annual yield rather than the P50, P75 and P90 bands a lender usually asks for. Larger commercial work, or anything with project finance behind it, needs a platform that carries through to documentation and banded yield.
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