A SMA Sunny Design alternative for European battery studies
If Sunny Design doesn't fit your sites or your budget: what Zorowatt does differently, what it costs per year and how to move a site over.
SMA Sunny Design is the inverter maker's PV design tool: free for PV design with your own load profile, with tariffs, peak shaving and time-series exports in Sunny Design PRO. Zorowatt does the battery economics only, brand-neutral, with the bill rebuilt from sourced tariffs. (sma.de)
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
- SMA Sunny Design
- Sunny Design PRO €600 a year, net
- 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 load-profile CSV you used in Sunny Design: Zorowatt reads a year of values with no dates from 1 January, or the dated export from the portal.
- 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 Sunny Design
- Pick Sunny Design if you design SMA systems: the free plan covers PV design with your own load profile, and PRO adds tariffs and peak shaving for €600 a year.
- When to pick Zorowatt
- Pick Zorowatt if you want tariffs, peak shaving and the bill check on the free analysis and the €49 plan, with batteries from many makers and inverters of any brand.
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 | SMA Sunny Design |
|---|---|---|
| Price | Free €0 · Starter €49 / month · Pro €149 / month · Enterprise on request | Free, with registration for own load profiles; Sunny Design PRO €600 a year, net, with a one-month trialsma.de · 2026-10-30 |
| Runs on | The browser; nothing to install | Web browser and tabletssma.de · 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 | Own load profiles on the free plan (a CSV from 1 January, 5 to 60 minutes); load-profile analysis on PROsma.de, manuals.sma.de · 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 | Custom purchase and feed-in prices and dynamic tariffs from time series, on PROsma.de · 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 | Peak-shaving simulation and multi-use with self-consumption, on PROsma.de, manuals.sma.de · 2026-10-30 |
| Battery products | A database of commercial and industrial products, every spec with its source | SMA battery inverters, with a compatibility list of batteriessma.de · 2026-10-30 |
| Solar | Planned solar modelled from PVGIS (EU Joint Research Centre) and laid on the meter data; existing PV is in the meter data (import and export) | PV design with shadingsma.de · 2026-10-30 |
| Client report | PDF report for the client; white-label on Pro | Project documentation; PRO adds a PowerPoint project exposésma.de · 2026-10-30 |
In short
Sunny Design is a free PV design tool with paid storage economics, built around SMA inverters. Zorowatt does the battery economics only, brand-neutral, with the bill rebuilt from sourced tariffs and checked against the invoices; it does not design the PV array.
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 Sunny Design 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.