Solar batteries: worth it or not? Are solar batteries worth it?

How a home battery storage system works

Solar panels generate electricity whenever there's daylight, but not always when you want to use it. Your house uses what it needs at that moment, and without a battery the rest goes to the grid. A battery keeps that spare solar so you can use it in the evening instead of buying electricity. That raises your self-consumption: the share of what your panels make that you use yourself. Many batteries can also charge from the grid overnight on a cheap tariff.

A few things worth knowing before you weigh up the cost:

• Size. Most solar batteries for homes are lithium-ion batteries of about 5 to 15 kWh, according to Which?. The Energy Saving Trust says a typical home system might have 10 kWh of storage capacity.
• Usable capacity. A battery should never empty fully, because that shortens its life. It stops at a set level, maybe 20%, so the usable capacity is less than the total capacity on the label.
• Power. The output in kilowatts limits how many appliances the battery can run at once. Above that, the rest comes from the grid.
• Losses. Using stored energy is a little less efficient than using electricity straight from the grid or your solar PV, so you get back slightly less than you put in.

Already have solar? See adding a battery to existing solar panels. For sizing, see what size solar battery you need.

A worked example

This is an illustration, not a promise. Start with how many kilowatt hours of spare solar you'd store, then multiply by the gap.

• A battery stores 5 kWh of spare solar a day on 200 days of the year: 1,000 kWh a year.
• On a basic export tariff, each of those units is worth about 20p more used than exported: about £200 a year.
• On a good export tariff, the gain is about 11p to 14p a unit: about £110 to £140 a year.
• A 5 kWh battery costs around £4,600 fitted, according to the Energy Saving Trust, and lasts 10 to 12 years.

On solar alone, that battery wouldn't pay back within its life. That's why the Energy Saving Trust is cautious, and why we price both options.

What solar batteries cost

The upfront cost is the biggest hurdle, and the Energy Saving Trust says it can make a battery unrealistic for some homes. It puts the range at £1,500 to £10,000, with a 5 kWh battery system around £4,600. MCS says the average cost of a battery storage installation on its data dashboard was around £9,000 in 2025. Installing battery storage at the same time as solar panels usually cuts installation costs, because the installer is already on site.

Batteries count as energy-saving materials for VAT. When an installer supplies and fits one in a home, it's zero-rated until 31 March 2027, including a battery added to an existing solar system. From 1 April 2027 the rate goes back to 5%. A battery you buy to fit yourself doesn't qualify. For prices by size, see our solar battery cost guide.

Solar panels without a battery: when that's the better buy

Solar panels work perfectly well without a battery. In a 2024 Which? survey of more than 2,000 solar owners, 43% also had a battery, so most were managing without one. Solar on its own tends to make more sense when:

• You're home in the day and already use most of what the system makes.
• You use little electricity in the evening.
• You've found a good export tariff and won't use a time-of-use import tariff.
• Your budget is tight. Solar on its own pays back faster; a battery can come later.

How the Smart Export Guarantee pays you

Without a battery, what you don't use is exported and paid for through the Smart Export Guarantee (SEG). You can choose any SEG supplier, not only the one that supplies your electricity, though the best rates usually go to their own customers. Rates ranged from 1p to 25p a unit in April 2026, according to Which?, and the highest were tied to buying your system from that supplier.

The Energy Saving Trust's figures, which include export payments, put payback for solar on its own at about 9 to 12 years. More in are solar panels worth it? and our Smart Export Guarantee guide.

If you might add a battery later, ask for a hybrid inverter now. It makes adding one cheaper and simpler.

So, are solar batteries worth it?

For homeowners who export most of their solar on a basic tariff, can charge overnight on a cheap tariff, or run an electric car or heat pump, often yes. For a home that's occupied all day, on a good export rate, with little evening use, solar on its own usually makes more sense. Look at your energy usage after dark and your tariffs, then run the sums. We price both options in your quote, so you can see what a battery would do to your energy bills before you decide.