A Sungrow iSolarDesign alternative for European battery studies
If iSolarDesign doesn't fit your sites or your budget: what Zorowatt does differently, what it costs per year and how to move a site over.
Sungrow iSolarDesign is the inverter maker's design tool, with a PV and storage optimiser for commercial sites that sizes Sungrow battery cabinets against time-of-use and demand charges. Zorowatt compares batteries from many makers and rebuilds the site's bill before sizing. (isolarcloud.com)
Five reasons consultants pick it.
- 01
The bill is checked against the invoices
Zorowatt rebuilds the bill from the meter data and sets it against each invoice, line by line, before it sizes anything. None of the tools we compared says it does this (checked 30 October 2026).
- 02
Dutch, German and Romanian tariffs, with sources
The 2026 tariffs of Liander, Stedin, Enexis, NEW Netz, Netze BW, RheinNetz and the Romanian ANRE zones are built in, each linked to its source. US tools leave European tariffs to you, in dollars.
- 03
Batteries from any maker
A database of 44 commercial products, every spec with its source. The free tools of Sungrow, SMA, Huawei and Victron size their own hardware only.
- 04
Prices on the page, from €0
A free analysis and free tools that need no account; Starter at €49 a month. Furo, Tibo, Gridcog and Energy Toolbase show no price before a call.
- 05
In the browser, in your language
A year of quarter-hours is simulated in about a second, with nothing to install, in English, Dutch, German and Romanian. HOMER, PVsyst and PV*SOL run on Windows.
Price per year
- Sungrow iSolarDesign
- No price or paid plan found; you register with an e-mail address
- Zorowatt
- Starter €588 a year (€348 at the founding price) · Pro €1,788 a year for 3 seats · single analyses €15
As each vendor's page states it; prices in other currencies are not converted.
How to switch
Upload the client's original meter export rather than the iSolarDesign template: Zorowatt reads the portal file directly and lists any gaps instead of filling them.
- Upload the site's meter data to the free data checker or the Workspace: every assumption made reading the file is listed.
- Pick the site's tariff and enter the invoices: the bill check shows whether the baseline matches before anything is sized.
- Size the battery, compare it with your earlier study, and send the client the PDF report.
- When to pick iSolarDesign
- Pick iSolarDesign if you install Sungrow storage: you register with an e-mail address and it sizes Sungrow cabinets against demand charges and time-of-use prices.
- When to pick Zorowatt
- Pick Zorowatt if you want to compare batteries from several makers, see the data gaps instead of having them filled, and have the bill checked against the invoices.
Facts about the other tool read on 2026-10-30 from the pages linked in each cell. Prices and features change; check the vendor's page before you rely on one.
| Feature | Zorowatt | Sungrow iSolarDesign |
|---|---|---|
| Price | Free €0 · Starter €49 / month · Pro €149 / month · Enterprise on request | No price or paid plan found; registration with an e-mail addressinfo-support.sungrowpower.com · 2026-10-30 |
| Runs on | The browser; nothing to install | Web and the iSolarCloud appinfo-support.sungrowpower.com · 2026-10-30 |
| Meter data import and checks | 15-minute or hourly data from CSV, Excel, German MSCONS or Green Button files, or a year of values with no dates; gaps, duplicates, daylight saving time and kW / kWh mix-ups flagged, never filled silently | Load profile imported from a template, or monthly kWh and maximum demand; missing data is filled automaticallyinfo-support.sungrowpower.com · 2026-10-30 |
| Tariffs | Versioned 2026 tariffs, each with its source: Netherlands (Liander, Stedin, Enexis, plus the ACM 2028 draft as a scenario), Germany (NEW Netz, Netze BW, RheinNetz, levies and Stromsteuer), Romania (ANRE zones). Any other country: a generic template where you enter the rates | Fixed or time-of-use energy prices, a demand or capacity charge, and a feed-in tariffinfo-support.sungrowpower.com · 2026-10-30 |
| Battery dispatch | Rule-based, with the optimal (LP) dispatch as the upper bound; every saving is billed by the same bill engine | Self-consumption, time-of-use and a demand-control threshold, or custom monthly plansinfo-support.sungrowpower.com · 2026-10-30 |
| Battery products | A database of commercial and industrial products, every spec with its source | Sungrow energy-storage productsinfo-support.sungrowpower.com · 2026-10-30 |
| Financials | NPV, IRR and payback, with degradation | Installation and O&M costs, a loan, a revenue forecast and ROIinfo-support.sungrowpower.com · 2026-10-30 |
| Client report | PDF report for the client; white-label on Pro | A downloadable design report with the revenue forecastinfo-support.sungrowpower.com · 2026-10-30 |
In short
iSolarDesign is the strongest no-cost tool for commercial storage we found, and it is built to sell Sungrow hardware. Zorowatt is vendor-neutral, reports data problems instead of filling them silently, and checks the rebuilt bill against the invoices; its first analysis is free, further ones are paid.
Try it on your own file first
Both tools run in the browser with no account; the file is not uploaded.
Meter data checker
Gaps, duplicates, daylight saving time, kW vs kWh and coverage in a meter export, before the study starts. No account, nothing uploaded.
Peak-shaving battery calculator
Battery size and payback for cutting a site's peak charges — from four numbers or your own load profile. No account, nothing uploaded.
Looking for a iSolarDesign alternative?
Zorowatt runs in the browser, reads the site's own meter data and rebuilds its bill before it sizes anything.
Switching?
Bring a site you already studied: upload its meter data and bills, and set the result next to your old one.