What do you need to consider before buying a home battery?
Before buying a home battery, it is important to look beyond price alone. The right choice depends on factors such as battery capacity, brand, installation requirements and whether you choose a plug-in or fixed system. These points all affect the total cost, performance and suitability of the battery for your home.
Battery capacity:
- Annual consumption: Look up how much total energy consumption you have on your yearly energy statement and divide the amount of kWh by 365 days. This gives you your daily average.
- Exported solar energy: This is the surplus a battery could have stored. Divide the annual figure by 365 for a daily average.
- Evening demand: How much you use after sunset decides how much of that stored energy you actually get back out.
Battery type:
The type of home battery has a major influence on the price. Fixed home batteries are generally more expensive because they often require additional equipment and professional installation by an electrician. Plug-in home batteries are usually more affordable and can often be installed by the homeowner without major changes to the electrical system. Even within the same category, prices can vary considerably between different battery models.
Battery brand:
The brand also affects the purchase price. Some manufacturers focus on affordable, straightforward systems, while others charge more for their name, design, software or additional features. Premium brands such as the Tesla Powerwall are usually much more expensive than many competing home batteries with a similar storage capacity. It is therefore important to compare not only the brand, but also the capacity, warranty, power output and included equipment.
The price different between a fixed installation and a plug-in home battery
| Capacity | Type | Price | Installation | Type | Price | Installation |
| 5 kWh | Plug-in | £1.250 to £1.500 | £0 with self-installation | Fixed installation | £5.000 | £1.000 to £3.000 |
| 10 kWh | Plug-in | £2.500 to £3.000 | £0 with self-installation | Fixed installation | £8.500 | £1.000 to £3.000 |
| 15 kWh | Plug-in | £3.500 to £4.000 | £0 with self-installation | Fixed installation | £10.000 | £1.000 to £3.000 |
| 20 kWh | Plug-in | £4.500 to £6.000 | £0 with self-installation | Fixed installation | £12.500 | £1.000 to £3.000 |
| 25 kWh | Plug-in | £6.250 to £7.000 | £0 with self-installation | Fixed installation | £15.000 | £1.000 to £3.000 |
| 30 kWh | Plug-in | £7.250 to £8.000 | £0 with self-installation | Fixed installation | £17.500 | £1.000 to £3.000 |
| 50 kWh | Plug-in | £10.000 to £12.000 | £0 with self-installation | Fixed installation | £20.000 | £1.000 to £3.000 |
| 60 kWh | Plug-in | £12.500 to £14.000 | £0 with self-installation | Fixed installation | £25.000 | £1.000 to £3.000 |
Which additional costs should you expect?
The additional costs depend on the type of battery and the work required during installation. A fixed home battery may require changes to the fuse box, such as adding a separate circuit or upgrading certain components. If you choose a DC-coupled system that connects directly to your solar panels, the panels may also need to be connected to a compatible hybrid inverter.
Installation costs are also influenced by how much time and labour the work requires. A simple installation will usually cost less than a system that needs new cabling, adjustments to the fuse box or changes to the existing solar installation. Some batteries already include an inverter, while others require a separate inverter, which increases the total price.
How much can you save with a home battery?
A home battery can reduce your energy costs in several ways. The amount you save depends on your electricity price, household consumption, solar generation and whether your energy supplier supports grid services.
Energy Arbitrage
With a time-of-use tariff, you can charge the battery when electricity is cheap and use it during expensive peak hours. For example, charging 10 kWh at £0.12 per kWh costs £1.20. Using that power when electricity costs £0.32 per kWh can save around £1.70 after energy losses.
Increasing Solar Self-Consumption
A battery stores surplus solar power so you can use it later instead of buying electricity from the grid. If you store 6 kWh and the difference between the import and export price is £0.13 per kWh, you save around £0.78.
Virtual Power Plants (VPP) and Grid Services
A Virtual Power Plant allows an energy company to use your battery to support the grid. In return, you may receive payments or bill credits. A payment of £15 per month would equal £180 per year.
A household might save around £250 per year through energy arbitrage, £200 by increasing solar self-consumption and £180 through a VPP programme. Combined, this would result in an estimated annual benefit of around £630. This is only an example, as actual savings can be higher or lower depending on electricity prices, battery efficiency and household use.
Is a home battery worth the investment?
For many households, a home battery can be a worthwhile investment, especially when it is used to store surplus solar energy, avoid expensive peak tariffs or participate in a grid services programme. Whether it is the right choice for your home depends on your electricity use, solar generation and energy contract. Use our configurator to find out which battery capacity suits your household and whether investing in a home battery could be a good next step.