What the quotation should list
- Panels: company, model, wattage and number of panels.
- Inverter: company, model and capacity, and whether it is on-grid, off-grid or hybrid.
- Batteries, if any: type, capacity and number.
- Mounting structure, cables, protection devices and earthing. Ask what material the structure is made of.
- Whether installation, any net-metering paperwork and later visits are included, or cost extra.
Ask about warranty and support
- Who gives the warranty on panels, inverter and batteries, and for how many years? Get it in writing.
- If the inverter develops a fault, who will you call, and how soon do they come? Ask for a phone number and an office or shop address.
- Ask to see their earlier installations or speak to someone who has used their work. Don't rely only on a social media page.
Warning signs
It is fair to compare at least two quotations. Check the roof, the panels and the wiring are all done safely before you pay the last part.
- The price is far lower than the others and the brands are not named.
- They ask for all the money before any work or delivery.
- They promise your bill will be zero without asking how much you use. Savings depend on your usage, system size and your electricity company's rules.