Polysun gets reviewed as if it were a PV design tool that happens to be unusual. That framing is wrong, and it makes the software look worse than it is. Polysun is a whole-system energy simulator that happens to include photovoltaics. Judge it against SketchUp-style layout tools and you will conclude it is missing half a product. Judge it against the question it was actually built to answer and almost nothing else in the market competes.
Direct answer. Polysun, from the Swiss firm Vela Solaris, dynamically simulates whole energy systems: photovoltaics, solar thermal, heat pumps, storage, hot water and heating in one integrated model. That capability is rare and genuinely valuable as heating electrifies. It is not a PV layout tool, a drawing-production tool, or a customer proposal platform. For most installers and EPCs, SurgePV covers those three in one browser licence.
TL;DR
- Polysun is the strongest tool in the category for sector-coupled simulation: PV, solar thermal, heat pumps, storage, and hot water modelled together over a year.
- That strength is growing more relevant, not less, because European heating is electrifying and PV now has to share a building with a heat pump.
- It is a simulation tool. It does not produce array layouts, single-line diagrams, drawing sets, or customer proposals.
- It is desktop-oriented, sold in editions with licence-based pricing, and quoted rather than listed.
- SurgePV covers 8,760-hour module-level design, single-line diagrams with DWG export, and a white-label proposal layer in one licence at $1,299 to $1,899 per user per year.
What Polysun Is and Who It Is Really For
Polysun is simulation software from Vela Solaris, a Swiss company. Its purpose is to model a complete building energy system dynamically over a year, not to draw a solar array.
You describe the components and how they connect. Photovoltaic generation, solar thermal collectors, a heat pump, a thermal store, a battery, the hot water draw, the space heating demand. Polysun then runs the system through time and reports how those parts behave together.
The intended user is an engineer or consultant designing integrated energy systems. Someone specifying a heat pump alongside PV for a Swiss or German house, or sizing a thermal store for a small commercial building. That person needs to know whether the array actually covers the compressor load, or whether the store is oversized for the draw pattern.
The person Polysun was not built for is the installer with 12 rooftop jobs a week and a permit queue. That is a scope statement, not a complaint.
Multi-Energy Simulation, and Why It Keeps Getting More Relevant
This section should be generous, because the capability deserves it.
Most PV software treats a building as a roof with a load curve attached. That was a reasonable simplification while heating ran on gas and PV was a separate purchase. It is becoming a bad simplification fast.
When a heat pump lands in the same building as an array, the load stops being a fixed profile. It becomes a thing that responds to weather, to the store temperature, and to control logic. Winter demand rises exactly when PV output falls. Hot water draws cluster at hours when the array produces nothing. A thermal store can absorb midday generation, or sit idle and waste it, depending on sizing and setpoints.
Polysun models that interaction dynamically. Not as an annual energy balance, but as a system moving through time where one component’s state changes another’s behaviour. Solar thermal and PV can be evaluated against each other rather than assumed. Storage, both electrical and thermal, gets simulated instead of estimated.
Almost nothing else does this properly. Plenty of tools bolt a heat pump estimate onto a PV model. Very few simulate the coupled system as one dynamic object, and that difference shows up in the answers.
If you sell integrated energy systems in a market where heating is electrifying, this is not a nice extra. It is the core engineering question, and Polysun answers it better than the alternatives. Anyone claiming a PV design platform substitutes for that is selling you something.
Our Germany solar design software guide covers the wider European tooling picture, and the HOMER Pro vs PVsyst comparison covers a related split between hybrid simulation and PV design.
What Polysun Deliberately Does Not Do
The limits are scope decisions. Vela Solaris never claimed this ground, so read the list as boundaries rather than failures.
It is not a layout tool for large PV arrays. You do not trace roof planes, place hundreds of modules around obstructions, resolve setbacks, and get a buildable arrangement out the other side. Polysun takes a system description.
It is not a drawing-production tool. No single-line diagram for the permit package, no DWG for the drafter, no sheet set for the crew. Drawing production happens somewhere else entirely.
It is not a customer sales proposal platform. There is no branded, white-label document with your logo and a savings narrative for a homeowner to sign. Polysun produces engineering output.
It is not the bankability reference. PVsyst still holds that position with lenders and independent engineers reviewing PV yield. That is a market fact, not a judgement on the engine.
It is desktop-oriented. Projects live on a machine, and sharing work in progress across a distributed design team carries the usual file-management friction.
Line those up and the shape is clear. Polysun answers a systems question with real depth. An installer’s day is mostly a specificity and paperwork question.
Polysun vs SurgePV: Two Different Jobs
Set this up honestly. Polysun and SurgePV are not really competitors. They sit at different points in a project and answer different questions. The table is about fit.
SurgePV is a browser-based solar design platform. It runs 8,760-hour simulation with module-level shading, mismatch, and string topology, produces single-line diagrams and DWG export from the same model, and includes a white-label proposal layer.
| The job | Polysun (Vela Solaris) | SurgePV |
|---|---|---|
| Primary question answered | How does this whole energy system behave over a year? | What exactly goes on this roof, and what do I hand over? |
| Intended user | Energy systems engineer, consultant | Installer, EPC designer, proposal engineer |
| Heat pump and thermal coupling | Core strength, dynamically simulated | Not claimed here |
| Solar thermal and hot water | Core strength | Not claimed here |
| Storage in a coupled system | Simulated with the rest of the system | PV design focused |
| Detailed PV array layout | Not its purpose | Yes |
| Module-level shading and mismatch | Not a layout-level concern | Yes |
| String topology | Not a layout-level concern | Yes |
| Hourly 8,760 simulation | Yes | Yes |
| Single-line diagram | Not provided | Produced from the same model |
| DWG export | Not provided | Produced from the same model |
| White-label customer proposal | Not provided | Included |
| Delivery | Desktop-oriented | Browser-based |
| Price | Licence-based, quoted by edition | $1,299 to $1,899 per user per year |
| Bankable PV yield standard | No, PVsyst holds that | No, PVsyst holds that |
There is no losing column in that table. If you read it as a scorecard you have misread it. It shows two tools pointed at different halves of a building.
Which Is Your Core Tool, and Which Is the Add-On
This is the useful framing, and it decides the purchase.
If your business is PV, Polysun is a specialist add-on. Most of your jobs are a roof, an array, a set of drawings, and a proposal. A minority are genuinely multi-energy, where a heat pump or a thermal store changes the engineering answer. For those jobs Polysun is the right tool, and buying a seat or two is sensible. It is not the thing your designers open every morning.
If your business is integrated energy systems, the ordering flips. Polysun is the core tool, because the coupled simulation is the deliverable your client is paying for. A PV design platform becomes the add-on that turns the accepted system concept into an array layout, a drawing set, and something the customer signs.
Most firms know which of those they are, then buy as if they were the other one. PV installers buy the systems simulator hoping it will also do layouts. Systems consultants buy a layout platform hoping it will model the heat pump. Neither purchase works, because neither tool was built to cover the other’s ground.
Decide the sentence “my business is X” first. The stack follows from it.
Try the software behind this review
Keep Polysun for the system. Run the PV work in a browser.
SurgePV runs 8,760-hour simulation with module-level shading, mismatch, and string topology, then produces the single-line diagram, the DWG, and the white-label proposal from the same model. One licence, one array, one number.
Book a free SurgePV demo →No credit card. 20-minute walkthrough on one of your own projects.
Polysun Pricing and Editions
Vela Solaris sells Polysun on a licence basis, in different editions, with pricing quoted rather than posted as a single public number. Treat any figure you find in a forum as unreliable and get a quote for the edition and seat count you actually need.
Two things are worth checking before you sign.
First, ask which edition carries the specific component models you are buying the tool for. Editions differ, and the most common budgeting mistake on any tiered simulation product is buying the cheaper tier and finding the capability you wanted sits above it.
Second, price the whole stack rather than the licence. Polysun covers simulation. Your layouts, drawings, and proposals still need a home, and those licences are part of the same annual number even though they arrive on separate invoices. Our solar design software pricing breakdown puts the category side by side.
What Most Buyers Get Wrong
They assume a simulation result is a design, so the design step quietly loses its owner.
Here is the mechanism. An engineer models the coupled system in Polysun and gets a defensible annual picture: generation, heat pump consumption, store behaviour, self-consumption. That output is genuinely good, and it feels like the hard part is finished. So the project moves on.
Now the array has to exist on a specific roof. A drafter opens CAD and places modules from scratch, choosing setbacks, string runs, and equipment positions that never existed in the simulation. Then sales needs a document, so a coordinator retypes the yield, the system size, and the savings into a template deck.
Count what happened. The system was simulated once in a tool that never held the array geometry, then built twice by hand in tools that never saw the simulation. Nothing propagates. Change the string configuration or drop 6 modules and 3 artefacts disagree until the AHJ or the customer finds it.
Put a number on it. Call it 90 minutes per project to build the layout and reconcile the proposal. At 120 projects a year that is 240 hours of skilled time spent recreating information the workflow should have carried.
Who Should Buy Which, and When to Run Both
Buy Polysun if you design integrated energy systems and the interaction between PV, a heat pump, thermal storage, and hot water demand is the engineering question your client is paying for. Nothing else covers that ground as well.
Run SurgePV as the daily driver if your job is putting modules on specific roofs and handing something to a customer and an inspector. It covers 8,760-hour module-level design, single-line diagrams with DWG export, and white-label proposals in one licence.
Keep PVsyst as well if a lender or independent engineer reviews your PV yield. That seat buys acceptance, not features.
Run Polysun and a design platform together if a meaningful share of your work is multi-energy. Polysun settles the system concept. The design platform turns it into an array, a drawing set, and a signed proposal. That sequence is coherent, and the tools do not overlap.
If storage architecture is the open question, our note on DC vs AC coupling covers the decision. If the bottleneck is drawing throughput rather than software, our solar rooftop detailed engineering design bench produces the construction pack directly. See a sample design pack or talk to our team.
The Verdict
Polysun is a serious piece of engineering software that is very good at something rare, and the rarity is real. Dynamic multi-energy simulation across PV, solar thermal, heat pumps, storage, and hot water in one model is not a feature other vendors have quietly matched. Vela Solaris earned that position.
Here is the opinionated call. For most installers and EPCs, Polysun is the wrong centre of gravity for a software stack in 2026. Not because the engine is weak, but because it answers a question that arises on a minority of your jobs, while the layout, the drawings, and the proposal arise on every single one. Buy it as a specialist seat, not as the platform.
SurgePV is the recommendation for that majority. Browser-based, 8,760-hour module-level modelling, single-line diagrams with DWG export, and a white-label proposal layer, in one licence at $1,299 to $1,899 per user per year. Buy Polysun when the heat pump is part of the answer. Buy SurgePV when the roof and the paperwork are what slow you down.
Conclusion
- Polysun wins outright on dynamic multi-energy simulation. PV with heat pumps, solar thermal, storage, and hot water in one model is a capability almost nothing else delivers properly.
- Its limits are scope, not quality. No array layout, no drawing set, no customer proposal, and it is desktop-oriented.
- Decide whether your business is PV or integrated energy systems. That answer tells you which tool is the core and which is the add-on, and most bad purchases come from getting it backwards.
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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
Is Polysun good software? Yes, for what it targets. Polysun dynamically simulates whole energy systems, including photovoltaics, solar thermal, heat pumps, storage, hot water, and heating in one integrated model. For sector-coupled residential and commercial design, that capability is genuinely distinctive and hard to replace.
Can Polysun design a PV array layout? No. It is a simulation tool, not a layout tool for large PV arrays. You do not get module placement around obstructions, setback resolution, or a buildable arrangement. That work belongs to a design platform.
Can Polysun produce permit drawings or customer proposals? No to both. Polysun is not a drawing-production tool and not a customer sales proposal platform. Single-line diagrams, DWG files, and branded proposals come from elsewhere, which is where the manual handoff appears.
Is Polysun bankable for PV yield studies? It is not the reference for lender-reviewed PV yield. PVsyst remains that standard with banks and independent engineers. Polysun’s value sits in system behaviour rather than in bankable single-technology yield certification.
How much does Polysun cost? Vela Solaris prices it on a licence basis by edition, quoted rather than publicly listed. Ask which edition carries the component models you need, and price the layout, drawing, and proposal tools alongside it as part of the same annual figure.
Should I replace Polysun with SurgePV? Only if your multi-energy work is marginal. They cover different ground. SurgePV handles design, module-level shading, single-line diagrams, DWG export, and white-label proposals in one licence. If heat pump and thermal coupling drives your engineering, keep Polysun and add the design layer next to it.
Related: the European tooling picture in best solar design software in Germany, the cost comparison in solar design software pricing, hybrid modelling in HOMER Pro vs PVsyst, and storage architecture in DC vs AC coupling.
