Are Home Batteries Worth It in the UK? (2026)

A battery quotation needs more than a purchase price. Record usable energy, continuous output, expected annual throughput, charging losses and warranty restrictions, then calculate what the unit adds to the household without crediting it for savings created by the solar panels. Energy Saving Trust’s £5,000–£8,000 storage range is a broad comparison only; the installed configuration and repeated energy shift determine whether that spending is productive.

Ofgem lists 26.32p/kWh for electricity and 7.97p/kWh for gas as average Direct Debit cap rates for 1 October–31 December 2026. A storage calculation should use the household’s actual import and export prices, because a national quarterly average cannot show the value of its charging window or the income surrendered when solar is retained.

Worth is not the same as technical capability. Backup power, resilience and lower peak imports may matter to a household, but attach a separate value to those benefits rather than disguising them as bill savings. Start with half-hourly import and export data wherever possible, then model a small battery before a large one.

Ask for two calculations: the whole solar-and-battery package, and the battery’s incremental case. The second should subtract export income lost when solar is stored, allow for charging losses and use a realistic number of cycles. If the sales proposal shows only combined savings, it does not prove the battery itself pays.

What changes the answer

Daily energy shape

Capacity should follow the evening energy that can genuinely be shifted, not annual consumption divided by 365. Winter solar surplus may be scarce while summer surplus may exceed storage.

Tariff spread

Grid charging works only when the difference between off-peak and peak prices remains large enough after losses and any tariff restrictions.

Usable capacity

Compare usable kilowatt-hours, not the larger nominal figure. Reserve settings, degradation and backup mode can reduce energy available for normal cycling.

Power output

A battery may contain enough energy yet be unable to run several high-load appliances together. Continuous output is more useful than an attention-grabbing peak figure.

Warranty economics

Read cycle, throughput and retained-capacity terms together. A long calendar warranty can still limit heavy tariff cycling.

Export opportunity

Stored solar is not free if it could have earned an export payment. Count that forgone payment in every battery calculation.

Rules and responsibilities for this topic

Network notification

Battery inverters can export to the distribution network. The installer should identify whether the design follows G98 notification or needs G99 approval before commissioning.

Electrical design

The quotation should state inverter rating, protection, earthing, isolation and whether backup circuits are separated safely from the grid.

Consumer evidence

Demand the current product data sheet, warranty, commissioning record, network paperwork and a written explanation of backup operation.

Decide whether storage earns its place

Start with half-hourly import and export data, not the battery capacity suggested during a sales call. Mark the electricity imported after solar generation falls, the surplus exported around midday and any dependable cheap-rate charging window. A useful unit must repeatedly move energy between those periods. Model a smaller capacity first, because unused capacity adds cost without increasing annual savings. Separate the value of backup power from bill savings; resilience can be worthwhile, but it is a household preference rather than a guaranteed financial return.

Ask for the battery-only calculation as well as the combined solar-and-storage forecast. The battery case should include charging losses, electricity bought for grid charging, export income sacrificed when solar is stored, and any reserve held for outages. Test the figures with a narrower tariff spread and fewer annual cycles. Compare the resulting payback with the warranty’s calendar, cycle and throughput limits. A model that assumes perfect daily cycling for longer than the warranted service is not a reliable basis for purchase.

Check whether continuous power is sufficient for the loads you expect to run together and whether backup requires extra switching equipment or a separate circuit. Confirm the proposed location, clearances, temperature limits, internet dependence and shutdown procedure. Request the DNO route, single-line diagram, commissioning record and written warranty before paying the balance. Use the battery comparison tool to place usable capacity, output and warranty terms side by side; do not choose from nominal kilowatt-hours alone.

Look at several weeks rather than one ideal day. Holiday periods, electric heating and vehicle charging can distort the pattern, while winter solar may leave little surplus to store. Ask for a month-by-month forecast showing charged energy, discharged energy and idle capacity. That evidence reveals whether the proposal depends mainly on summer solar, regular tariff arbitrage or an unrealistic blend of both. It also makes later monitoring meaningful: actual throughput can be compared with the sales case before the warranty period is far advanced.

Questions to ask the installer

1. What usable capacity is available at the proposed reserve setting?
2. How many full-equivalent cycles does my interval data support?
3. What continuous output is available on-grid and during backup?
4. Which G98 or G99 route applies to this inverter?
5. What export income is lost in your savings model?
6. Which warranty clause limits cycles, throughput or retained capacity?

Keep the battery forecast beside the quote so its cycling assumptions can be challenged.