Home Batteries: Store Today, Use When It Matters
Find out how home batteries can store your solar electricity, help you use more of your own energy, reduce your bills and provide backup power.
- Use more of your own solar energy
- Lower electricity bills
- Backup power for added peace of mind
Independent homeowner guide · Battery costs and funding checked 31 October 2026
Battery savings depend on electricity tariffs, solar generation and usage. Backup power requires compatible equipment and installation.
Home Batteries: What Are They and Should You Get One?
A home battery stores electricity so you can use it later — for example, solar power generated at lunchtime when you're out, or cheaper electricity bought overnight. It can reduce how much expensive electricity you buy, but a battery is not always a good financial investment.
Already have solar?
Store some daytime surplus for the evening rather than exporting all of it. Compare the value of stored power with the export payments you give up.
No solar panels?
A battery can still charge from the grid on a suitable cheap-rate tariff. Savings require a worthwhile tariff difference and enough regular usage.
Need blackout protection?
Check for a dedicated backup or emergency supply arrangement. A standard grid-connected battery may switch off during a power cut.
How Does a Home Battery Work?
- Electricity arrives from your solar panels, the grid or both.
- The battery charges when you have spare solar electricity or buy energy at a lower tariff rate.
- A control system decides when to charge, hold energy or supply power to the house.
- You use stored electricity later, subject to the battery's capacity, output power and the way it has been configured.
Does it work with solar panels?
Yes. A battery can increase the proportion of your own solar electricity you use at home. Solar panels normally produce more during daylight and summer; your need for electricity may be greatest in the evening or winter. A battery moves electricity across hours, not across seasons.
Can you have a battery without solar?
Yes. You may be able to charge using an overnight or other off-peak electricity tariff and discharge when the import tariff is higher. This only works financially if savings after round-trip losses and any extra tariff charges justify the price. Check whether your supplier's tariff allows the intended battery charging arrangement.
Can it help with a heat pump or electric vehicle?
Potentially. Higher electricity demand can make a well-managed battery more useful. But home heating and EV charging can use energy quickly. Ask whether the battery's usable storage and maximum discharge power can meet the loads, and compare with simply scheduling the heat pump or EV to use a cheaper tariff directly.
Which Battery System Should You Look For?
AC-coupled and DC-coupled systems
| System | What it means | Common situation |
|---|---|---|
| AC-coupled | The battery connects through a battery inverter on the home's AC side. Energy may pass through multiple conversion steps. | Often a flexible way to add storage to an existing solar installation. |
| DC-coupled | Solar and battery use a compatible hybrid inverter or linked DC equipment. | Often considered when solar and batteries are installed together. |
| Modular battery | Storage capacity is built from compatible units. | Useful if future expansion is needed, subject to the system's limits and warranty. |
Battery chemistry: Many home systems use lithium-ion technology, including lithium iron phosphate (LFP). Compare the product's certified safety features, warranty, usable capacity, temperature limits and installation requirements rather than assuming all batteries of one chemistry are alike.
What do kWh and kW mean?
kWh (kilowatt-hours) is the amount of energy the battery can store or deliver. Think of it as the size of a water tank. kW (kilowatts) is how quickly the battery can deliver power — like the size of the tap. A battery with plenty of stored energy can still struggle to run several powerful appliances at once if its output is limited.
Usable capacity is the energy you can normally take from the battery, which may be smaller than the marketed nominal capacity. Round-trip efficiency is how much electricity you get back after charging and discharging; some energy is lost as heat and in conversion.
What Size Home Battery Do You Need?
There is no universal best size. Start with the amount of electricity you need to shift from cheap hours or sunny hours to the evening. A battery that is too small may leave useful surplus unused; one that is too large may sit partly empty and earn too little to justify its price.
| Illustrative usable capacity | What to explore | Key question |
|---|---|---|
| 3–5 kWh | Smaller evening demand or limited solar surplus. | How many kWh would you actually shift most days? |
| 5–10 kWh | Moderate household usage or larger solar systems. | Can you charge and discharge it often enough across the year? |
| 10+ kWh | Higher demand, heat-pump households or a specific backup requirement. | Will extra capacity earn enough extra benefit to cover its price? |
These are shopping discussion ranges, not recommendations based on household size. Energy Saving Trust notes that a typical system may be about 10 kWh; the right size depends on your household's consumption and available charging opportunities.
A simple way to think about capacity
Suppose your home normally uses 4 kWh between sunset and bedtime, and you have enough spare solar or cheap-rate electricity to recharge each day. A battery with approximately 4–5 kWh usable capacity might cover much of that period, provided its kW output is sufficient. But if you can only fill it for a few months, or you have a strong export tariff, the economics will change.
Ask for calculations based on 12 months of half-hourly smart-meter readings where available, plus real solar generation estimates or monitoring data. Make sure the proposal includes realistic winter days, degradation and any minimum reserve level.
How Much Does a Home Battery Cost — and Save?
Energy Saving Trust gives a broad battery cost range of approximately £1,500–£10,000 and a benchmark of about £4,600 for a 5 kWh system. Larger capacities, backup equipment, upgrades and difficult installation locations can cost more. These are published guidance figures, not personalised quotations.
Example A: storing spare solar electricity
Imagine that you use 4 kWh from the battery on a suitable day. At 90% round-trip efficiency it takes about 4.44 kWh to charge. If purchased electricity is 28p/kWh but you could otherwise export solar electricity for 12p/kWh, the incremental saving is:
| Illustrative calculation | Amount |
|---|---|
| Grid electricity you avoid buying (4 × £0.28) | £1.12 |
| Export income forgone (4.44 × £0.12) | About £0.53 |
| Net benefit per suitable day | About £0.59 |
| If this occurs on 250 suitable days | About £147/year |
Illustration only, not a forecast: assumes the battery has enough usable capacity, no additional fees, all avoided imports are at 28p and all diverted export is worth 12p. Real-world charging cycles and time periods will differ.
Example B: charging cheaply from the grid
If you buy 4.44 kWh at 10p/kWh overnight and deliver 4 kWh later instead of buying it at 28p/kWh, the saving is approximately £0.68 per cycle. Across 250 such cycles, that is about £169 per year, before standing charges, tariff fees, other losses or battery wear.
How long would it take to repay?
If a battery costs £4,600 installed and delivers an incremental saving of £200 a year, simple payback is 23 years (£4,600 ÷ £200). That may exceed the practical or warranted life of the equipment. Changing tariffs, solar export rates, electricity usage, maintenance or replacement cost can alter the result.
Solar export payments
The Smart Export Guarantee (SEG) may pay qualifying households for eligible electricity exported to the grid. Export rates and conditions differ between suppliers, and battery-charged grid electricity is not automatically eligible for payment under every arrangement. Compare your export tariff terms before deciding to store rather than export electricity. Ofgem SEG information.
Will Your Battery Keep the Lights On During a Power Cut?
Not necessarily. A grid-connected solar and battery installation normally has safety measures preventing it from energising the external network during an outage. Supplying your home during a power cut requires a properly designed backup or emergency-power arrangement, compatible inverter and safe separation from the grid.
- Whole-home backup may be possible but can need expensive extra equipment and sufficient output capacity.
- Essential-circuits backup might supply selected lights, broadband, fridge or other chosen circuits.
- Battery size matters: a 5 kWh battery cannot supply a constant 5 kW load for long, and some of its energy may be held in reserve.
- Solar during an outage depends on whether the system supports safe islanded solar operation; do not assume panels can recharge the battery in a blackout.
Where Can a Battery Go? Safety, Installation and Maintenance
Home battery installations involve stored electrical energy and fire risks. Use an appropriately qualified and insured installer experienced in battery energy storage, and follow the manufacturer's specifications, relevant electrical regulations and applicable industry guidance (including PAS 63100 where relevant).
Location and fire safety
A battery may be suitable in a garage, a purpose-designed outdoor location or another approved space. The right place depends on product rating, weather exposure, temperatures, safe clearances, wall strength, access, ventilation, fire separation and escape routes. Do not assume an attic, hallway, bedroom or under-stairs cupboard is suitable. Obtain a documented site-specific safety assessment.
Grid connection and approvals
In Great Britain, battery storage installations must be notified to the relevant Distribution Network Operator (DNO); some connections need approval before work. Ask the installer which G98/G99/G100 process applies and retain the submitted or approved documentation. GOV.UK guidance on registering energy devices.
Planning permission and building-control requirements depend on location, building and UK nation. Listed buildings, conservation areas, external units and unusual installations may need extra checks. Ask the installer to document the applicable permissions rather than assuming an exemption.
What about lifespan and warranties?
A battery gradually loses capacity over time. Compare both the years of warranty and the warranted energy throughput, cycles and end-of-warranty capacity. Check whether labour, call-outs and failed inverters are included, whether warranty terms require internet connectivity, and what happens if the supplier stops trading.
Homeowner maintenance is generally limited to keeping approved areas clear, monitoring system alerts and arranging professional checks when needed. Never open a battery pack or modify its wiring yourself. Tell your home insurer about the installation and keep safety documents.
Grants, Loans and VAT: What Is Available in the UK?
Financial support depends on location and eligibility. Do not assume every household can get a free battery. Some programmes fund batteries only alongside solar panels or as part of a wider assessed improvement plan.
UK-wide: Warm Homes Loan Scheme
Government guidance lists battery storage among the eligible improvements under the Warm Homes Loan Scheme, subject to lender and property eligibility, approved installer conditions and availability. This is loan funding, not a free grant. Confirm terms, repayment obligations and whether the proposed product meets the scheme rules. Check Warm Homes Loan Scheme eligibility.
England: Warm Homes: Local Grant
For eligible low-income households with qualifying privately owned or rented homes, local authorities may arrange energy upgrades. Government scheme guidance permits solar PV batteries only alongside existing or new solar panels and where they deliver energy-bill savings; a battery by itself is not an automatic funded measure. A survey and local approval determine what is installed. Check local grant eligibility.
Wales: Nest and local support
The Welsh Government's Nest programme can provide energy advice and a tailored package to households meeting its eligibility rules. Do not assume battery storage is covered; ask Nest what specific measures can be funded at your property. Wales Nest programme.
Scotland: Home Energy Scotland
Home Energy Scotland offers energy advice and information about finance. Its published homeowner Grant and Loan table does not currently show a general standalone battery-storage grant. The availability of any other financing should be confirmed before installation. Home Energy Scotland battery advice and current grant and loan terms.
Northern Ireland
Different local schemes, suppliers and regulatory arrangements apply. Seek up-to-date advice from NI Direct or Northern Ireland Housing Executive, and verify any offer directly with the named programme. Do not assume the Great Britain DNO or SEG arrangements are identical.
VAT on home battery installations
From 1 February 2024, qualifying professionally supplied and installed battery storage systems, including standalone batteries charged from the grid, can benefit from 0% VAT under the temporary energy-saving materials relief. Under current legislation the zero rate runs to 31 March 2027; a 5% reduced rate is scheduled afterwards. Separately buying equipment for DIY use does not automatically qualify. Ask the installer to show the VAT treatment in writing. HMRC Notice 708/6, battery section.
Funding and tax information checked 31 October 2026. Scheme availability, funding caps and lender terms can change. Check official conditions before signing a contract or paying a deposit.
How to Choose a Battery Installer
- Gather your energy information. Have 12 months' bills and smart-meter readings, and solar generation/export data if available.
- Decide your objective. Solar self-use, cheaper tariff periods, backup power or a combination?
- Get three itemised quotations. Compare a battery with a no-battery baseline and ask about alternative sizes.
- Check installer competence. Look for appropriate electrical qualifications, relevant MCS certification and insurance; verify scheme claims.
- Confirm safety and grid processes. Get the location assessment, DNO route, isolation/backup arrangements and approvals in writing.
- Keep your handover pack. Ask for commissioning certificates, user instructions, warranties, monitoring access and a safe shutdown procedure.
Questions to ask before you buy
- What are the usable kWh and continuous/peak kW output, and can the battery be expanded?
- How many times per year will your model actually fill and discharge using my half-hourly electricity data?
- What are the estimated annual savings after efficiency losses and lost export income, and what tariffs are assumed?
- Which backup circuits are included, if any, and how is grid disconnection handled?
- What is covered by warranties, and what are the terms for degradation and cycle limits?
- Who arranges DNO notification, electrical certification, removal of old equipment and insurance documentation?
- What happens if the internet, app or tariff service fails? Can I still safely use the battery?
Common Homeowner Questions
Do I need solar panels to have a home battery?
No. A battery can store off-peak grid electricity, but the tariff difference needs to outweigh energy losses and the installed cost.
Will a battery make my electricity bill zero?
Almost certainly not. You may still need to import electricity, pay standing charges and buy energy during low-sun periods. The outcome depends on usage and tariffs.
Can I use my battery during a power cut?
Only if the system has compatible backup equipment and appropriate safety arrangements. Confirm exactly which circuits will work.
Is a bigger battery always better?
No. You pay for capacity that may go unused. The right size depends on realistic daily charging opportunities, consumption and the battery's output power.
Can I add a battery to existing solar panels?
Often yes. AC-coupled storage can suit retrofits, though compatibility, inverter capacity and DNO requirements need to be checked.
Will a battery work with my heat pump or EV charger?
Potentially, but both can draw substantial power. Compare battery output and storage with tariff-based scheduling without storage.
What is the difference between 5 kWh and 5 kW?
5 kWh describes stored energy. 5 kW describes a rate of delivering power. You need to check both when planning household or backup loads.
Where is the safest place to put the battery?
There is no one answer for every property. A suitably qualified installer must select and document a location that meets the product requirements and applicable electrical and fire-safety guidance.
Will I still receive money for exported solar electricity?
Possibly. Your Smart Export Guarantee eligibility and tariff depend on supplier terms and qualifying metering. Storing solar electricity can reduce what you export.
Do I qualify for a battery grant?
Not automatically. Some means-tested or council-supported schemes may fund battery measures, often alongside solar, while other arrangements are loans. Check official eligibility before work starts.
How long will the battery last?
Battery capacity reduces with age and use. Compare warranty years, energy throughput, cycles and promised remaining capacity rather than a single lifespan claim.
What Should You Do Next?
Begin with your electricity data, not the battery brochure. Work out how much energy you use after sunset or during expensive tariff periods, and how much solar or cheap electricity is realistically available to charge a battery. Then ask reputable installers to show the financial case clearly.
Useful official and independent sources: Energy Saving Trust — Battery Storage · Energy Saving Trust — Battery and Tariff Research · Ofgem — SEG · GOV.UK — Energy Device Registration · HMRC — VAT.