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Zorowatt vs Sungrow iSolarDesign

Where iSolarDesign is strong, where it falls short, and what changes if you switch. Every number can be checked on their site.

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)

Short answer
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.

FeatureZorowattSungrow iSolarDesign
PriceFree €0 · Starter €49 / month · Pro €149 / month · Enterprise on requestNo price or paid plan found; registration with an e-mail addressinfo-support.sungrowpower.com · 2026-10-30
Runs onThe browser; nothing to installWeb and the iSolarCloud appinfo-support.sungrowpower.com · 2026-10-30
Meter data import and checks15-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 silentlyLoad profile imported from a template, or monthly kWh and maximum demand; missing data is filled automaticallyinfo-support.sungrowpower.com · 2026-10-30
TariffsVersioned 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 ratesFixed or time-of-use energy prices, a demand or capacity charge, and a feed-in tariffinfo-support.sungrowpower.com · 2026-10-30
Battery dispatchRule-based, with the optimal (LP) dispatch as the upper bound; every saving is billed by the same bill engineSelf-consumption, time-of-use and a demand-control threshold, or custom monthly plansinfo-support.sungrowpower.com · 2026-10-30
Battery productsA database of commercial and industrial products, every spec with its sourceSungrow energy-storage productsinfo-support.sungrowpower.com · 2026-10-30
FinancialsNPV, IRR and payback, with degradationInstallation and O&M costs, a loan, a revenue forecast and ROIinfo-support.sungrowpower.com · 2026-10-30
Client reportPDF report for the client; white-label on ProA 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.

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.

  1. Upload the site's meter data to the free data checker or the Workspace: every assumption made reading the file is listed.
  2. Pick the site's tariff and enter the invoices: the bill check shows whether the baseline matches before anything is sized.
  3. Size the battery, compare it with your earlier study, and send the client the PDF report.

Questions

Does iSolarDesign cost anything?
No price or paid plan was found; its user manual describes registration with an e-mail address (read on 2026-10-30). The battery choices are Sungrow products. Zorowatt Starter is €49 a month for 3 site analyses, then €15 each; Pro is €149 a month with a white-label report and 3 seats. Your first site analysis is free, with no card.
Why does it matter that missing data is filled automatically?
Because a filled gap can hide a stuck meter or a shutdown, and the battery is then sized on invented load. Zorowatt lists every gap and asks how to treat it; the report says how much of the year was measured.
Can I size a Sungrow battery in Zorowatt?
Yes, if it is in the battery database, next to products from other makers; or enter its capacity, power and efficiency yourself.

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.

iSolarDesign alternative for C&I battery studies in Europe →

Switching?

Bring a site you already studied: upload its meter data and bills, and set the result next to your old one.