Will solar and battery storage protect me during a blackout or a heatwave?

A home battery can provide backup power in an outage, but only if your system is set up for it. A standard grid-tied system shuts down with the grid, for safety.

Why solar does not automatically mean backup

Grid-tied systems must switch off during an outage so they cannot feed power into the network while engineers work. To keep power on, you need extra equipment:

• An automatic transfer switch that isolates your home from the grid
• A battery and inverter rated for backup operation
• A separate backup circuit for essentials such as the fridge, lights and some sockets

This must be specified when you get quotes.

Trade-offs

Backup-rated systems cost more. Whole-home backup needs a bigger battery and inverter, while essential-circuit backup is cheaper. As a guide, a 10 kWh battery might run essentials for a day, but cannot power a whole home indefinitely without sun.

Ask your installer

• Is this grid-tied only, or does it include backup?
• Does everything stay on in an outage, or just certain circuits?
• How long could the battery run my essentials with little solar?
• Does backup change my eligibility for export payments?

Frequently asked questions

Can I add backup later?

It depends on your inverter and battery. It is usually easier and cheaper to specify it from the start.

Does a battery still help without backup?

Yes. The bill savings case is separate from backup capability.

All figures are modelled estimates for typical UK rooftops, not guarantees for any individual home. Rules, funding and eligibility can change, so check current government and supplier guidance before deciding.

Next guide: Where in the UK could you get the best return on solar and battery? →