How much does a solar battery cost in the UK

If you have solar panels and want to use more of your own power, a battery is the usual answer. This guide shows how much a solar battery costs in the UK, what drives the price, and how to work out whether it will save you money. You will get clear figures, a sizing method you can use now, short case studies from real installs, and a checklist for installers.

How much does a solar panel battery cost?

A typical 5kWh battery fitted at the same time as panels costs around £3,000 to £4,000. A 10kWh battery fitted with panels costs about £4,000 to £6,000. These figures include installation and inverter where needed.

Is a solar battery worth it?

A battery is worth it if it raises self‑consumption and shortens your payback period. For households with high evening demand, or on time of use tariffs, batteries give clear value. For low consumption homes, the payback can be long.

How long do solar batteries last?

Most modern lithium-ion home batteries have a useful life of 10 to 12 years, depending on cycles and warranty terms.

How prices break down

Typical battery sizes and price bands

• 5kWh fitted with solar panels: £3,000 to £4,000.
• 10kWh fitted with solar panels: £4,000 to £6,000.
• 15kWh fitted with solar panels: £5,000 to £7,000.

These bands assume the battery is fitted at the same time as the solar installation. Adding a battery later costs more because installers must return, and you may need a new inverter.

What installation covers

A standard installation price normally includes the battery unit, the battery inverter or hybrid inverter where required, standard cabling and labour, basic mounting and commissioning, and safety sign off. It does not include any structural work, major rewiring, or upgrade of your consumer unit.

Factors that affect the cost

Battery chemistry and capacity

Lithium-ion batteries are the most common for homes. They cost more than lead-acid but have longer life and better depth of discharge. Lead-acid batteries are cheaper up front but need replacement more often and need maintenance.

Inverter and hybrid systems

If you already have a solar inverter, a battery install may need an additional hybrid inverter or an AC coupled solution. Buying a single hybrid inverter and battery at the same time can reduce the overall cost compared with retrofitting.

Labour, cabling and roof access

Complex installs increase labour time. If the battery has to be mounted internally or in a loft, or if cabling runs are long, expect higher costs. Properties with difficult access will also see higher labour charges.

Warranty and cycle life

A longer warranty and higher guaranteed cycle count add cost. Focus on usable capacity and cycle warranty rather than headline kWh. A battery with a 10 year warranty that guarantees 70% capacity after 5,000 cycles offers more predictable lifetime cost than a cheaper unit with a short warranty.

Short case studies

Case study 1: three-bedroom semi, new install with 5kWh battery

Background. A three-bedroom semi installs a 4kWp solar array and a 5kWh battery at the same time. Annual electricity use 3,800kWh.

Costs. Panels and 5kWh battery combined cost £7,500. The battery portion was about £3,200, including inverter and labour.

Performance. Self-consumption rose from roughly 35% to 65. The household saved about £280 a year on their electricity bill at typical 2025 tariffs.

Outcome. Simple payback only on the battery alone is long, but the household benefits from lower import and greater resilience.

Case study 2: retrofit battery on older property

Background. An older property with 3kWp of panels chooses a 10kWh battery later. The house needed a hybrid inverter upgrade.

Costs. The retrofit battery install was £6,200 because the inverter upgrade added cost. Some additional trunking and consumer unit work added £400.

Performance. Evening usage fell by 70% for the hours covered by stored solar. Savings were £320 a year.

Outcome. Retrofitting costs more. If you plan battery storage, fit it at the same time as panels where possible.

How to size a battery for your home

Quick calculation method

1. Find your average daily electricity use in kWh, from a year of bills.
2. Decide how many hours of evening autonomy you want. For example, 3kWh to cover lighting and fridge overnight.
3. Allow for usable capacity. A 5kWh battery often has about 3.3kWh usable if the battery has 66% usable depth. Check the spec.

Example. If your evening demand is 6kWh, a 5kWh battery with 3.5kWh usable will not cover it. A 10kWh unit with about 7kWh usable will be closer.

Questions to answer before you buy

• What is your average daily kWh?
• When do you use most electricity? Day or evening?
• Do you need resilience in a power cut?
• Are you on a time of use tariff?

VAT, grants and financial incentives

Since February 2024 solar batteries have been on the zero VAT list for energy saving materials until the end of March 2027. That rule removes VAT from standalone battery purchases until that date. After March 2027 the government plans to increase the VAT rate on these items to 5 percent.

There are also targeted grants including Warm Homes funds and local authority schemes for low income or energy inefficient households. These grants change by region and by funding windows.

Savings, payback and ROI calculations

How to estimate savings

1. Estimate how much exported solar you will store instead of exporting to the grid.
2. Multiply stored kWh by your avoided import price.
3. Subtract any additional standing charges or maintenance costs.

Example simple model. A 5kWh battery might increase annual self consumption by 20 percentage points. On a household using 3,800kWh a year, that is about 760kWh redirected from export to consumption. If your avoided import price is £0.30/kWh, the saving is £228 a year.

What affects payback speed

• Your electricity price and export rate.
• How much of your generation you can store and use.
• Battery round trip efficiency.
• Tariff structure, including time of use tariffs.

Buying and installation checklist

• Confirm battery usable capacity and round trip efficiency.
• Ask for and read the full warranty document.
• Check whether the inverter is included and whether it is hybrid.
• Get a full written cost breakdown.
• Ask about ongoing monitoring and software fees.
• Confirm who is responsible for disposal and recycling at end of life.

Comparison table: what to check on spec sheets

• Nominal capacity (kWh) and usable capacity.
• Cycle warranty and capacity retention at end of warranty.
• Round trip efficiency.
• Dimensions and weight.
• Communication protocols and app features.
• Safety certifications and fire protection notes.

Common mistakes and how to avoid them

• Buying based on headline kWh only. Compare usable kWh and warranty.
• Choosing lead-acid purely for lower price. Lifetime cost often higher.
• Not checking compatibility with existing inverter.
• Forgetting to account for installation complexity.

FAQs

How much does a solar panel battery cost to install separately?

Retrofit installs often cost more. A 5kWh battery added later can cost several hundred to over a thousand pounds more than a same-time install because of labour and additional inverter work.

What is the solar panel and battery cost for a typical house?

For a typical UK house a combined solar panels and battery cost might range from £6,000 to £12,000 depending on array size and battery capacity.

How much does a solar panel battery storage cost for a 5kWh unit?

A 5kWh battery storage cost fitted with panels is roughly £3,000 to £4,000.