Facts last checked 17 September 2026
The short answer
The Energy Saving Trust puts a home battery at anything from £1,500 to £10,000 installed, with a 5 kWh system at around £4,600, and its July 2026 research used £6,200 as a mid-range figure from 2025 MCS installation data. Installing a battery in a home is zero-rated for VAT until 31 March 2027, including a standalone battery charged from the grid. On a flat-rate tariff a battery saves nothing; on a time-of-use tariff a 5 kWh battery emptied at peak every day might save up to about £310 a year on our stated assumptions. With a typical life of 10 to 12 years, it often does not pay for itself on its own.
What does a home battery cost in 2026?
Prices depend mainly on usable capacity, the inverter and how much electrical work is needed. These are the most reliable published figures we could find:
| What | Typical installed cost | Source |
|---|---|---|
| Any home battery | £1,500 to £10,000 | Energy Saving Trust |
| 5 kWh battery system | Around £4,600 | Energy Saving Trust |
| Standard domestic system, mid-range | £6,200 | Energy Saving Trust research, based on 2025 MCS installation data |
| 8 solar panels plus a 5 kWh battery, typical 3-bed | £8,500 to £13,000 | Our published range |
| 12 solar panels plus a 10 kWh battery, larger home | From £13,500 | Our published range |
The Energy Saving Trust says a typical home system might be 10 kWh, and that fitting a battery at the same time as solar panels should save money because the installers are already on site. Smart Energie does not publish a price for a standalone battery or for adding one to existing panels. Those are priced after a survey, because the inverter, consumer unit and location vary so much.
What pushes the price up or down?
- Usable capacity. This is the energy you can actually draw. The Energy Saving Trust notes systems stop discharging at a set level, perhaps 20%, to protect the battery, so compare usable kWh, not the headline figure.
- The inverter. A hybrid inverter can run solar panels and a battery together. Adding a battery to older panels may need a separate battery inverter.
- Backup power. Keeping some circuits running in a power cut needs extra switching and wiring, and not every system offers it.
- Location. Fire safety guidance restricts where a battery can go (see below), which can mean longer cable runs or an outdoor enclosure, and some indoor positions need interlinked smoke alarms.
- Electrical upgrades. A consumer unit with no spare capacity, or a connection that needs network operator approval first, adds cost and time.
Is there VAT on a home battery?
Not until 31 March 2027. HMRC's VAT Notice 708/6 says that from 1 February 2024 electrical storage batteries installed in homes qualify for the temporary zero rate. That covers:
- a battery fitted as part of a new solar installation
- retrofitting a battery to existing solar panels
- a standalone battery storing electricity from the grid
- a battery storing electricity from both solar panels and the grid
The zero rate applies when the installer supplies and fits the battery. From 1 April 2027 these installations are due to revert to the reduced rate of 5%.
How much can a battery save on a time-of-use tariff?
A battery only saves money by moving your electricity use from a high price to a lower one. So the gap between your tariff's peak and off-peak rates does most of the work. Here is a simple best-case calculation, with every assumption stated so you can change it:
- Time-of-use tariff: 16p per kWh overnight and 35p per kWh at other times. These are the Economy 7 style rates the Energy Saving Trust modelled in its July 2026 research, not a real offer. Check your own tariff.
- Flat tariff for comparison: 26.32p per kWh, the Ofgem price cap for October to December 2026.
- The battery charges fully overnight and is completely used at peak rate every day of the year. Real homes often fall short of this, especially in summer.
- Round-trip efficiency of 90%, our assumption. The Energy Saving Trust notes that storing and releasing energy always loses some.
| Usable capacity | Time-of-use tariff (16p and 35p) | Flat tariff (26.32p) |
|---|---|---|
| 5 kWh | About £314 saved | About £53 lost |
| 10 kWh | About £629 saved | About £107 lost |
The working for 5 kWh: to deliver 5 kWh the battery buys about 5.56 kWh at 16p (89p) and avoids 5 kWh at 35p (£1.75), a gain of 86p a day, or about £314 a year. On a flat tariff the same cycle buys 5.56 kWh to replace 5 kWh at the same price, so you lose the 10% that went missing.
Modelling of more realistic usage comes in well below that best case. The Energy Saving Trust's Flexible futures research, assuming a 9 kWh battery and half-hourly household demand, found median savings of about £320 a year on a dynamic tariff and £250 on Economy 7 in a gas-heated home with no solar, and none on a standard tariff. With a heat pump, savings rose to around £420 to £570 on dynamic tariffs, but a heat pump home on a flat tariff could see running costs rise by about £150.
How long does a battery last, and what should the warranty say?
The Energy Saving Trust gives a typical lifespan of about 10 to 12 years, shorter than solar panels, so expect to replace a battery before the panels. Its July 2026 research assumed 10 years, which it says reflects typical manufacturer warranty periods for home lithium-ion systems.
Batteries lose capacity gradually as they are charged and emptied, and faster if they are regularly run flat, which is why systems keep a reserve. Read the warranty rather than the brochure. Check:
- how many years it lasts, and whether the installation is covered as well as the product
- the capacity the battery is guaranteed to keep at the end of the term
- any limit on total energy throughput or cycles, which can end the warranty early if the battery cycles every day
Do you need to tell the network operator?
Yes. A battery counts as generation when it exports and as demand when it imports, so the grid connection rules for solar apply to it too. MCS sets out the two routes:
| Route | When it applies | What happens |
|---|---|---|
| G98 | Total inverter output up to 16 amps per phase (about 3.68 kW on a normal single-phase supply) | Install first, then notify the network operator within 28 days of commissioning |
| G99 | Above 16 amps per phase | Apply to the network operator and get approval before connecting |
A battery added to existing solar can push the total over 16 amps, so ask your installer which route applies and allow extra time if it is G99. Your installer should handle the paperwork.
Where can a battery safely go?
PAS 63100:2024, the BSI specification for protecting home battery systems against fire, says batteries should be installed outdoors where practicable. It rules out:
- bedrooms, and cupboards or spaces opening into them
- escape routes, including landings, staircases and hallways
- lofts, roof spaces and voids
- outdoor positions within 1 metre of doors, windows, escape routes or ventilation openings
- within 2 metres of stored flammable materials or fuel tanks
- cellars or basements with no access to the outside
Where a battery goes in an infrequently visited place such as a store cupboard, it calls for an interlinked smoke alarm there. It also limits a single enclosure to 20 kWh and the total in a house to 40 kWh, or 80 kWh in a garage or outbuilding with suitable fire separation, or outdoors. MCS has noted that PAS 63100 is not itself written into regulations, but it is referenced through the IET code of practice installers follow. Treat an installer who proposes your loft or landing as a warning sign.
When does a battery not pay?
Be cautious if any of these apply:
- You are on a flat-rate tariff and do not plan to switch. The battery has nothing to shift and loses energy doing it.
- You use little electricity in the evening peak, so the battery never empties.
- You already have solar and a good export rate. The Energy Saving Trust found about £210 a year from adding a battery in that case, with payback longer than the battery's life.
- You expect to move within a few years.
- The money would do more elsewhere, such as insulation, which our insulation cost guide covers.
If you have solar or are considering it, read solar with or without a battery, check what solar panels cost, or try our payback tool with your own numbers.
Common questions
How much does a 10 kWh home battery cost?
There is no single official figure for 10 kWh. The Energy Saving Trust gives a range of £1,500 to £10,000 for home batteries and around £4,600 for 5 kWh, and its research used £6,200 as a mid-range installed cost. Get an itemised quote that states usable capacity.
Is a standalone battery zero-rated for VAT?
Yes. Since 1 February 2024 HMRC has zero-rated installing a standalone battery that stores electricity from the grid in a home, until 31 March 2027.
Can I have a battery without solar panels?
Yes. It charges when your time-of-use tariff is at its lower rate and runs your home at peak times. The Energy Saving Trust says it saves more running a heat pump than storing solar alone.
How many years will a home battery last?
The Energy Saving Trust gives a typical lifespan of about 10 to 12 years. Check the warranty for the capacity it guarantees at the end of the term and any throughput limit.
Can a battery go in my loft?
Not under PAS 63100:2024, which excludes lofts, roof spaces, bedrooms and escape routes such as landings and hallways. Outdoors, a garage or a suitable utility space is usually where it goes.