Rooftop solar for a small business: what to ask before you sign

Rooftop solar can cut a shop's or small factory's power bill for many years — but only if the system is sized properly and installed by someone who will still pick up the phone after year one. These are the questions worth asking every installer.

Start from your electricity bill

Keep your last few months' bills ready. The units you use each month, and when you use them, decide the system size far more than the size of your roof. Share the bills with installers and ask how they arrived at the capacity they are proposing.

On-grid, off-grid or hybrid?

• On-grid systems work alongside the grid and are usually the simplest where power supply is regular
• Hybrid systems add batteries for backup during cuts
• Off-grid systems run independently of the grid

Explain how often you face power cuts and which equipment must keep running. Let the installer justify the choice.

What should be included in the price

1. Panel make, type and wattage, and how many
2. Inverter make and capacity
3. Mounting structure — material and height
4. Wiring, earthing and lightning protection
5. Net-metering and approval paperwork, if the installer handles it
6. Monitoring app or display
7. Warranties: panels, inverter and workmanship — listed separately

Two quotes with the same kilowatt figure can differ a lot in what they include. Put them side by side against this list.

After-sales service

Ask who cleans the panels and how often, what happens if generation drops, and how quickly they respond to a fault. A local installer with a service team in your city is often the safer choice.

Before you sign

Ask for a site visit, a written generation estimate, and the names of two or three installations you can see or call. Check that the final agreement lists every item from the quote.

Browse solar installers and suppliers or post your requirement with your monthly units, roof area and city.