Polysun is the tool most PV software comparisons get wrong, because they judge it as a PV package and it is not one. It is a dynamic multi-energy system simulator from Vela Solaris AG in Winterthur, Switzerland, and photovoltaics is one technology inside a model that also carries solar thermal collectors, heat pump cascades, buffer tanks, combined heat and power, district heating and PVT hybrid panels. On our bench it scores 30 of 50, and the shape of that score is more useful than the number: a 9 on simulation depth sitting next to a 3 on proposal and sales workflow. Vela Solaris does not publish prices, which we treat as a scoring fact rather than a mystery. This review covers where Polysun is genuinely the only sensible answer, and where it is the wrong purchase entirely.
Direct answer. Polysun is Swiss multi-energy simulation software from Vela Solaris covering PV, solar thermal, heat pumps and hybrid systems in one dynamic model. Pricing is not publicly listed. It scores 30 of 50 on our bench: deep physics, weak sales workflow. Best for engineers designing combined heat and power systems where PV is one component. Not suitable for high-volume PV-only proposal work.
If you have arrived here comparing Polysun against a cloud proposal platform, the two products are not competing for the same hour of your day. That comparison is worth making anyway, and it is the second half of this page.
What Polysun Is
Polysun simulates energy systems for buildings and districts. You assemble a hydraulic and electrical system from components, define the control logic, and the software runs a dynamic simulation across the year to tell you what the whole assembly actually does.
The history is longer than the company. Vela Solaris’ own history page states that “The Polysun software goes back to simulation models and programs developed by Martin Zogg as early as 1975” and that it was further developed by the Institute for Solar Technology SPF at the University of Applied Sciences Rapperswil in Switzerland from 1992. The company is headquartered at Stadthausstrasse 125, 8400 Winterthur, Switzerland, per its own company site. Widely repeated accounts describe Vela Solaris AG as a 2006 spin-off from SPF; we could not confirm that founding year on a Vela Solaris page during this review, so we state it here as unconfirmed rather than asserting it.
What that academic lineage buys you is credibility on the thermal side, which is where the product is unusual. The published product range lists four commercial editions:
- Polysun Standard, for standard projects and variant comparison.
- Polysun Designer, adding custom hydraulic circuits and project-specific control logic.
- Polysun SPT, focused on building-mounted photovoltaics for installers and PV planners.
- Polysun Enterprise and API, a cloud simulation service for corporate integration.
Student and educational licences are also published. Vela Solaris states the Designer edition draws on “150,000 deposited energy system components” and “1,000 practice-tested templates for energy system concepts,” which is a component library aimed at engineers rather than salespeople.
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Book a free SurgePV demo → Compare pricingThe 5-Axis Review Bench
This is the Heaven Green 5-Axis Review Bench, the published frame we apply to every tool on this site. Ten points per axis, fifty total, axes stated so the score is auditable.
| Axis | What it measures | Polysun | Notes |
|---|---|---|---|
| Design and simulation depth | Dynamic physics, sub-hourly behaviour, control logic, multi-technology coupling | 9 / 10 | Best multi-energy modelling we have benched. Loses a point on PV-specific layout ergonomics. |
| Compliance and documentation output | Technical reports, CAD export, permitting artefacts | 6 / 10 | Strong technical reporting and CAD export of roof plans and string layouts. No market-specific permitting workflow. |
| Proposal and sales workflow | Branded interactive proposal, financing, e-signature, CRM | 3 / 10 | Reports exist. A sales pipeline does not. |
| Price against value | Total cost for the work delivered | 5 / 10 | Docked for opacity as much as for cost. Buyers cannot compare what they cannot see. |
| Support and onboarding | Training, documentation, responsiveness | 7 / 10 | Serious documentation, a 30-day trial on every edition, engineering-grade learning curve. |
| Total | 30 / 50 |
Verdict. Polysun is a physics tool with a report generator attached, not a sales tool with physics attached. Score it on what a thermal engineer needs and it is near the top of the category. Score it on quotes per week and it is near the bottom.
Pricing
Vela Solaris does not publish figures. We fetched the official pricing page during this review and it lists the editions, a 30-day free trial on each, and buy links, with no prices on the page itself. So the honest answer is: not publicly listed.
| Edition | Published price | Licence model as published |
|---|---|---|
| Polysun Standard | Not publicly listed | Purchase or lease |
| Polysun Designer | Not publicly listed | Purchase or lease |
| Polysun SPT | Not publicly listed | Purchase or lease |
| Polysun Enterprise and API | Custom, contact required | Contract |
| Polysun Designer Student | Educational rate, not publicly listed | Valid student ID required |
Source: Vela Solaris pricing page, fetched 2 August 2026. We deliberately publish no number in the first column, because we could not source one from Vela Solaris during this review. Third-party directories carry old figures, including a Designer price from a 2013 price list, and reprinting a thirteen-year-old number as current would be worse than admitting the gap.
What Vela Solaris does publish is the licence structure, and that part is genuinely useful. The pricing page states that “The purchase license is a one-off payment for permanent usage rights” with annual service subscriptions for continued updates and support, while “lease license offers flexible monthly payments with a minimum term of 12 months.”
📘 Buying note
A perpetual licence with an optional annual service fee is a materially different commitment from a pure subscription. If you use a tool twice a quarter, perpetual usually wins. Our solar design software pricing guide works through both models.
The opacity costs Polysun points on our value axis. In our own experience of running software shortlists, a buyer comparing five tools on a Tuesday afternoon tends to shortlist the ones that let them see a number.
What Polysun Does Best
Multi-energy system simulation, which is the genuine moat. Almost every tool in our best solar design software roundup models photovoltaics and stops. Polysun models solar thermal systems, heat pump sizing against a simulated heating load, heat pump cascades, combined heat and power, district heating and cooling networks, geothermal and waste heat recovery, PVT hybrid panels, battery storage and buffer tank sizing, and it does so in one coupled dynamic model. If your project is a hotel where the roof carries PV and thermal collectors and the basement carries a heat pump and a buffer tank, none of the PV design platforms on our bench will answer your question. Polysun will.
Project-specific control logic. The Designer edition lets an engineer define the control strategy rather than accept a template. In a hybrid system the control strategy is usually where the annual performance actually lives, and being able to model your own is the difference between a simulation and a guess.
A component library sized for engineering. Vela Solaris states 150,000 deposited components and 1,000 tested system templates. Starting from a validated template and modifying it is a faster and safer route than assembling a novel hydraulic scheme from scratch.
Serious PV capability in the SPT edition. This is not a thermal tool that pretends about PV. Polysun SPT is described as delivering “precise energy yield simulations and advanced string planning,” with 3D building visualisation and terrain, automatic and manual inverter sizing, multi-roof planning with snow and wind load calculations, CAD export of roof plans and string layouts, self-consumption and solar coverage analysis, and reports for customers. Our performance ratio glossary entry explains the metric these engines are ultimately arguing about.
Storage and sector coupling modelled together. Batteries, EV charging and heat pumps sit in the same simulation as the array. That is exactly the analysis our solar plus storage design software guide says most tools approximate.
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Where Polysun Falls Short
There is no sales workflow, and that is the honest headline. Polysun produces technical reports and customer-facing PV reports. It does not produce a branded interactive proposal with financing options, e-signature and a CRM behind it. If your business converts leads by sending a good-looking proposal within 24 hours of a site visit, Polysun is not the tool that does that job and does not claim to be. Compare the Solargraf review or the OpenSolar review for what that end of the market looks like.
PV-only workflow depth is not where the investment has gone. For a straightforward rooftop PV design, faster tools exist. The ergonomics that make a residential designer productive across 40 roofs a week, meaning satellite-driven roof capture, one-click layouts, template pricing, are not Polysun’s focus.
Pricing opacity is a real cost to the buyer. Not publishing a number pushes a discovery call in front of a trial decision. Some buyers will simply not make that call.
Learning curve. Defining hydraulic circuits and control logic is engineering work. A salesperson will not be productive in this tool, and Vela Solaris is not pretending otherwise.
No market-specific permitting or subsidy workflow. As of August 2026 we found no MCS shading factor for the UK, no CEC and STC handling for Australia and no PM Surya Ghar arithmetic for India. Compare our Easy PV review and SolarPlus review for tools built the opposite way, deep in one jurisdiction and shallow in physics.
No drone or as-built capture. Site verification is someone else’s job. See the Scanifly review.
⚠️ Watch out
Do not buy Polysun to replace a proposal tool. The teams we have seen try it ended up quoting in a spreadsheet instead.
Who Should Buy Polysun
The reader for whom Polysun is the right purchase, ahead of every other tool on this site including our own sister product:
You are a building services or energy systems engineer whose projects couple PV with thermal or heat pump plant. A hospital retrofit, a district heating scheme, a hotel with solar thermal for hot water, a housing block where a heat pump cascade, a buffer tank, a battery and a rooftop array all interact. Your deliverable is a technical report that another engineer will interrogate, not a proposal a homeowner will sign. You need to define your own control logic because the standard one does not describe your plant.
For that engineer, none of the PV design platforms we have benched is an alternative, including ours. SurgePV will simulate your array beautifully and will not tell you what the heat pump does to the self-consumption profile in February. That reader is real and Polysun is the correct answer for them.
A second reader: consultancies and universities. The perpetual licence option, the educational tiers and the depth of the component library suit an environment where the same seat is used intensively for months and then not at all.
Who Should Not Buy Polysun
High-volume residential PV installers. You need speed and a proposal, and this is the wrong shape of tool. Start with the residential solar design software guide.
Anyone who needs a branded customer proposal as the primary deliverable. See the Pylon review or the Arka 360 review.
Utility-scale PV developers. Terrain-driven layout optimisation at hundreds of megawatts is a different discipline. Our RatedPower review and PVcase review cover it.
Buyers who need a lender-recognised PV yield report specifically. Polysun is a credible simulator, and in the financed projects we have worked on the name a project finance team expected to see on a PV yield report was usually PVsyst. Read the PVsyst review before deciding.
Teams that need a price before a sales call. A legitimate procurement policy, and it rules Polysun out at the first gate.
Polysun vs SurgePV
Disclosure, stated plainly: SurgePV is a sister product of Heaven Green Energy and we run it daily on our own EPC projects. That is first-party operating experience and a commercial interest at the same time. Read the table with both in view.
| Axis | Polysun | SurgePV | Honest read |
|---|---|---|---|
| Solar thermal, heat pumps, CHP, district heating | Modelled natively in one dynamic system | Not modelled | Polysun, and it is not close. |
| Custom control logic | Designer edition, project-specific | Not available | Polysun. |
| PV yield simulation | Strong, engineering-grade | 8,760-hour with P50/P75/P90 on every paid plan | Roughly level for PV. Different strengths. |
| Branded proposal, e-signature, CRM | Reports only | Native | SurgePV. |
| SLD and BOQ | CAD export of roof plans and string layouts | Native auto-generated | SurgePV. |
| Speed on a routine rooftop | Slow, engineering workflow | Fast, satellite-driven | SurgePV. |
| India workflow (PM Surya Ghar, DISCOM tariffs) | None | Native | SurgePV. |
| Published price | Not publicly listed | $1,299 per user per year on the 5-user plan | SurgePV, on transparency alone. |
| Licence model | Perpetual purchase or 12-month minimum lease | Subscription | Polysun, for occasional users. |
| Brand track record | Swiss lineage back to 1992 SPF development | Launched 2025, thin brand recognition | Polysun. |
| Drone or as-built capture | None | None | Neither. |
| Structural stamping | Snow and wind load calculations, not stamped | Not available | Neither. |
| Racking database | Component library is thermal-heavy | Thinner than its module and inverter libraries | Neither is strong here. |
SurgePV’s weaknesses are named in that table deliberately. It launched in 2025 and carries far less brand recognition than a product with a Swiss research lineage, it has no drone capture, it does not do structural stamping, and its racking database is thinner than its module and inverter libraries. It also does not model a single solar thermal collector, which for the reader described two sections up is disqualifying.
The dividing line is honest. If heat is part of your system, buy Polysun and do not let a PV platform talk you out of it. If your work is PV, storage and a customer who needs a proposal, one platform that designs, simulates and sells costs less than a simulator plus the proposal tool you will buy next to it. That is the case for SurgePV’s simulation engine sitting under the same proposal.
How Heaven Green Energy Uses This In Practice
We are an EPC before we are a software opinion. Our design team runs SurgePV daily across residential, commercial and industrial work out of Gujarat.
Polysun is not in our daily stack, and the reason is our project mix rather than a criticism of the tool. Indian commercial rooftop work is overwhelmingly PV plus, increasingly, battery storage, and the thermal side of our market is served by separate solar water heating contractors rather than integrated into the same design. Where we do meet a coupled system, typically a hotel or a hospital with solar water heating alongside the array, the honest position is that our own platform would not answer the thermal question and a Polysun-class simulator would.
What we take from it is a discipline about control logic. On a battery project, the annual result is decided by the charge and discharge strategy far more than by the module datasheet, and a tool that lets you model your own strategy rather than accept a default is worth the extra hours. The IRENA renewable energy statistics show how quickly storage and heat coupling are growing as a share of new capacity, and the design tooling has not caught up with that shift in most markets.
For clients who need coupled thermal and electrical engineering documented properly, we point them at Heaven Designs’ battery energy storage resource centre, and for hybrid inverter selection the QBits Energy hybrid inverter range is where our own storage projects usually start.
For readers on the buying side rather than the building side:
- Residential Solar: 1 to 10 kW rooftop with PM Surya Ghar handled start to finish.
- Commercial Solar: 10 to 100 kW with ROI modelling and depreciation planning.
- Industrial Solar EPC: 100 kW+ turnkey.
- Solar Calculator: subsidy and 25-year savings in 60 seconds.
Other evaluations in this series: PV*SOL review, HelioScope review and Aurora Solar review. The category overview is our solar design software pillar.
Frequently Asked Questions
How much does Polysun cost in 2026?
Not publicly listed. Vela Solaris’ official pricing page lists the Polysun Standard, Designer, SPT and Enterprise editions with a 30-day free trial on each, but does not display prices on the page. Figures are shown in the buy flow or provided on request. The page does publish the licence structure: a purchase licence is a one-off payment for permanent usage rights with annual service subscriptions, and a lease licence is a monthly payment with a minimum term of 12 months.
Who makes Polysun?
Vela Solaris AG, headquartered at Stadthausstrasse 125, 8400 Winterthur, Switzerland. The company’s own history page states the Polysun software goes back to simulation models developed by Martin Zogg from 1975 and was further developed by the Institute for Solar Technology SPF at the University of Applied Sciences Rapperswil from 1992. Vela Solaris is often described as a 2006 SPF spin-off, which we could not confirm on a Vela Solaris page.
What makes Polysun different from PV design software?
It simulates the whole energy system rather than the array. Solar thermal collectors, heat pumps and heat pump cascades, combined heat and power, district heating and cooling, geothermal and waste heat recovery, PVT hybrid panels, batteries and buffer tanks are all modelled together with the photovoltaics in one dynamic simulation. None of the PV design platforms on our bench model that side, which is why Polysun has few real competitors for hybrid building energy projects.
Does Polysun generate customer proposals?
It generates reports, including customer-facing PV reports from the SPT edition, but not a branded interactive sales proposal with financing options, e-signature and CRM tracking. If proposal turnaround is your bottleneck, Polysun will not fix it. Pair it with a dedicated sales platform or choose a tool that covers both jobs.
Which Polysun edition should a PV installer buy?
Polysun SPT is the edition aimed at solar installers and PV planners working on building-mounted systems. It covers yield simulation, string planning, automatic and manual inverter sizing, 3D visualisation with terrain, multi-roof planning with snow and wind load calculations, and CAD export of roof plans and string layouts. Designer is the edition to choose only if you need custom hydraulic circuits and your own control logic.
Is Polysun bankable for project finance?
Polysun is a credible engineering simulator with a long research lineage, and it is not the name we have seen most project finance teams write into their yield report requirements. For PV specifically, the lenders we have dealt with have asked for PVsyst by name. Confirm the required methodology with the lender before choosing a tool, because that requirement is contractual rather than technical.
Polysun or SurgePV, which should I choose?
Choose Polysun if solar thermal, heat pumps or combined heat and power are part of the system and you need to model your own control logic. Choose SurgePV if your work is PV and storage and you need a branded proposal, SLD and BOQ, fast satellite-driven rooftop design, or India workflows such as PM Surya Ghar. SurgePV launched in 2025, has no drone capture and no structural stamping, and models no thermal plant at all.
Does Polysun work for the Indian market?
The physics works anywhere with weather data. We found no market-specific layer for India, meaning no PM Surya Ghar subsidy arithmetic, no DISCOM (distribution company) net metering tariff library and no Indian documentation workflow. Indian engineers on hybrid thermal and PV projects still find it useful as a simulation tool, with the commercial and regulatory work done elsewhere.
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