What Sets the Cost of Solar Battery Storage in the UK

◆What sets the cost of home battery storage

A battery stores the power your panels make in the middle of the day. You use it in the evening instead of buying from the grid. Without one, that power goes to the grid and you buy it back later at a higher price.

Batteries fitted at a home are zero rated for VAT, on their own or alongside panels. HMRC's guidance says the zero rate runs to 31 March 2027. After that, from 1 April 2027 these will revert to the reduced rate of VAT of 5%. It covers the battery, the inverter and the labour.

◆The batteries we fit

Anker SOLIX X1

This is the unit on most of our published projects. Anker's own product page lists LiFePO4 cells, 5 kWh battery modules, and a system that scales from 5 kWh up to 180 kWh. Power output runs from 3 kW to 36 kW. Anker quotes a 10 year warranty and round trip efficiency of up to 90.2%.

Round trip efficiency is the share of the power you put in that you get back out. The rest is lost as heat.

The 5 kWh module size is the useful part for a house. You can often start at the size you need and add a module later. That only works within the limits of the power module and inverter fitted. It needs the installer to reconfigure the system, and some systems cannot be expanded at all without replacement.

Fox ESS ECS4800

We also fit Fox ESS. The ECS4800 datasheet, version 2.0 dated 1 December 2023, lists LiFePO4 prismatic cells. The smallest configuration, the ECS4800-H2, is rated at 9,320 Wh. It stacks up to seven modules, which takes it to 32,610 Wh.

The same datasheet gives round trip efficiency above 95%, depth of discharge of 90%, a cycle life of 6,000 and an IP65 rating. Depth of discharge is how much of the stated capacity you can actually use.

A note on GivEnergy

We used to list GivEnergy here. We no longer recommend it for a new installation. Companies House shows GivEnergy Ltd, company number 11571089, with the status "In Administration". Existing systems generally keep working, but a hardware warranty is only as good as the company behind it.

If you already have a GivEnergy battery, talk to us before you replace anything. It may well be fine.

◆How much a battery saves you

The point of a battery is to raise your self consumption. That is the share of what your panels make that you use yourself rather than export. Every unit you keep is a unit you do not buy at the grid rate.

The Ofgem price cap sets that grid rate for most households. It is 26.11p per kWh from 1 July to 30 September 2026, rising to 26.32p per kWh from 1 October. Export pays less than that. Smart Export Guarantee rates run at 4p–15p per kWh. The gap between the two is what a battery is worth to you.

A solar and battery system together saves £700–£1,200 a year for a typical home. We work your own figure out at the survey, from your bills and your roof.

◆Charging a battery overnight

Some tariffs charge much less at night. A battery can fill up on cheap overnight power and run the house through the expensive evening hours. That works with or without solar panels.

◆Can I add a battery to solar I already have?

Usually yes. The thing to check is the inverter. Some older string inverters cannot take a battery directly, so the battery needs its own inverter, and that costs more. We look at your existing kit during a free survey and tell you which route is cheaper.

If you are having solar fitted now and might want a battery later, say so. We can choose an inverter today that takes a battery later without being replaced.

◆Where a battery goes

A battery needs a dry, ventilated spot with room around it. A garage or a utility room usually works. Lofts and roof spaces do not. PAS 63100:2024, the UK fire safety specification for home batteries, rules them out. The Fox ESS unit is rated IP65, but an ingress rating on its own does not settle the position. Outdoors has to suit the installation manual and the survey: the clearances around the unit, the temperature and humidity limits, and nothing covering it. We agree the position at the survey, not on the day.

◆Common Questions

How much does a home battery cost in the UK?

Price depends on how much storage you want and whether it goes in with new panels or on its own. Fitting it alongside a new solar system is cheaper than coming back later, because it is one visit and one set of scaffolding. Ask us for a fixed price after a survey.

What size battery do I need?

It depends on how much power you use in the evening, not on how big your roof is. Two homes with the same panels often want different batteries. Both the Anker and the Fox ESS systems are modular, so starting smaller and adding capacity later is often possible. It depends on the power module and inverter fitted, and it needs the installer to reconfigure the system.

Is battery storage worth it without solar panels?

It can be, if you are on a tariff with cheap overnight power. The battery charges at the low rate and runs the house at the peak rate. You are not generating anything, so the saving comes purely from the price difference.

Do I pay VAT on a home battery?

No. Batteries fitted at a home are zero rated, on their own or with panels. HMRC's guidance says that runs to 31 March 2027 and then goes back to the reduced rate of 5%.

How long does a home battery last?

Look at the cycle life and the warranty rather than a number of years. The Fox ESS ECS4800 datasheet quotes a cycle life of 6,000. Anker quotes a 10 year warranty on the SOLIX X1. We fit units with 10-year inverter and battery warranties.

◆Next steps

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