Check your total electricity use in kilowatt-hours over at least the past 12 months, if possible. Look for seasonal changes and take your bills or retailer usage data to the installer so the proposed system can be sized against your actual demand.

Identify how much electricity you use during daylight hours and which loads, such as hot water, appliances or EV charging, could be moved into solar-generating hours. Using more electricity while your panels are generating can reduce the amount you need to buy from the grid.

Ask your installer to estimate how much solar electricity your household will use as it is generated and how much will be exported, month by month if available. This is known as self-consumption and is often where a household receives the greatest value from solar.

Confirm the proposed export level, whether an export limit may apply and who will obtain network approval before the system operates.

Ask your installer to confirm whether your property has a single-phase or three-phase supply, whether generation must be balanced across phases, and which inverter configuration and settings are required. These technical details can affect the system design, how much electricity it can export and what is required for connection to the Northpower network.

Compare buy-back rates alongside import prices, fixed charges, time-of-use periods, contract terms and any metering requirements.

Compare the upfront cost with likely bill savings, useful capacity, expected life, warranty and whether backup power requires extra equipment or dedicated circuits.

Ask your solar installer for the total installed cost, expected annual savings, simple payback period and assumptions about electricity prices, export rates, panel degradation, maintenance and finance.

Check the roof’s orientation, shading, usable area, structural condition and remaining life. Ask whether repairs or replacement are likely during the life of the panels, and how removing and reinstalling the system would affect costs and warranties.

Ask whether the system includes an app or online portal that shows generation, household use, imports and exports. Check whether monitoring access is included, whether there are ongoing fees and who will help if the system is not performing as expected.

Check that the installer and electrician are suitably qualified, and ask who will manage the network application, installation, commissioning and after-sales support. Confirm what the workmanship and product warranties cover, how long they last and who to contact if something goes wrong.