Should I get a battery for my home?

Photo credit: Powervault

Home batteries are definitely having a moment. These smart devices for storing large amounts of electricity can be installed in garages, cupboards and on external walls, and typically have the capacity to power the equivalent of several electric kettles running constantly for a whole hour. They are a great addition to a low-carbon home, allowing homeowners to store their excess solar power and charge up at cheap overnight rates, saving money and reducing emissions. Installations from certified installers in the UK have soared, reaching an average of 1,100 per month in 2024, but are still far below installations of solar panels or heat pumps. In addition to falling global prices, this growth has been driven by a government decision to remove VAT on battery storage in February 2024, which has spurred homeowners to get one installed.

But despite the falling costs, getting a battery installed still requires a hefty upfront investment - installing a medium sized battery will set you back around £5-6k. Many people, including some on the SmartShift Energy team, are asking the question, “Is a home battery right for me?”.

We’ve crunched the numbers to help you decide. Whatever stage of electrification your home is at, we have a recommendation for you! 

Adding batteries to a solar installation ✅

If you already have solar panels or are thinking of having them installed, getting a battery is a great way to get the most bang for your buck. Despite increasing the size of your initial investment, a battery will actually help reduce your payback period. That’s because they allow you to store the excess electricity your panels generate while the sun is out and use this to power your house through the evening and into the night. While you can also choose to sell any surplus back to the grid, you’ll likely receive at best 15p per kWh for this electricity. Instead, charging a battery allows you to avoid buying electricity in the evening, which costs about 25p per kWh on even the cheapest tariffs.

Combining your battery with a smart tariff can make your investment even more cost effective - as well as charging for free when the sun’s out, you can charge up from the grid during the cheap overnight period. Then, you can use this electricity to cover your usage until the sun is shining again. And because you can charge up whenever it is cheapest, you can completely avoid paying expensive peak prices.

Our analysis suggests that installing a battery alongside solar can bring your payback period down to around eight years if you’re on a smart tariff, compared to a standard period of at least 15 years for a stand-alone solar installation If you’re having a battery retrofitted to an existing system, your installation costs may be higher - however, this would bring your payback period to ten years at most. 

Installing batteries in a home with no solar and no other smart devices❌

While a battery can help you save on electricity costs, the upfront investment is just too high right now to make it worthwhile unless you have other smart devices. Firstly, not having solar panels means you have no opportunity to charge for free from your excess generation. And while you can still take advantage of smart tariffs, the cost benefit of charging up on off-peak electricity to skip the evening peaks just won’t be enough for most people. 

Our analysis suggests that solo battery owners are currently looking at a payback period of around 15 years if they use their battery effectively alongside smart tariff. That’s longer than the warranty on most batteries, and far greater than on battery + solar installations.  In this case, we believe you’re better off putting that money towards solar panels. If you’re still looking to benefit from smart tariffs but solar isn’t an option, getting a heat pump or an EV is probably a smarter move.

Installing a battery in a home without solar alongside other smart devices 🤔

It’s hard to tell whether installing a battery to complement your heat pump or EV is a good idea. That’s because the flexibility of these smart devices already allows you to take advantage of time-of-use tariffs. These devices tend to have a much higher power requirement and would wipe out the battery’s charge pretty quickly if you tried to power them from it. And while installing a larger battery is an option, this would also drive up the initial investment required. 

As a result, it’s unclear whether adding a battery would allow you to significantly improve the cost of electricity for these homes. You would still be able to profit from buying cheap electricity and selling it at high peak times, but again, this will leave you looking at a payback period of about 15 years, with very little benefit to your existing smart devices. Thus, there’s no clear rationale for installing a battery alongside other smart devices. Instead, a better idea is saving up for solar AND a battery, which could completely transform your household’s electricity usage.

Conclusion

We realise that every home is unique, and there are cases where households might benefit from getting a battery without solar. With that in mind,we hope these recommendations are helpful in deciding if a battery is right for your home. Right now, it only really makes sense to get a battery installed if you’re using it alongside solar panels. However, this is a space worth watching. As prices continue to fall, batteries will start making sense for a lot more people. Our analysis suggests that if battery prices were to halve, installing a battery would make sense in all cases, with or without solar. 

However, it’s worth noting that all of our analysis is based on using a battery in the most effective way possible. Used poorly, a battery is always a bad choice; used well, it can both drive down your bills and support the country on its pathway to decarbonisation. Reach out to us at hello@smartshiftenergy.co.uk if you want to learn more about what you can do.