Solar batteries in the UK: who they make sense for (and who should skip them)
A clear, numbers-first guide to UK home batteries: what they actually do, when they save money, when they don’t, and how to sanity-check the decision using your own usage pattern.
Solar batteries in the UK: who they make sense for (and who should skip them)
A home battery sounds like the missing piece: store your solar, use it later, slash your bill.
Sometimes that is true. Sometimes it is an expensive way to feel “more self-sufficient” without actually changing the economics.
If you want a quick baseline for what solar output looks like where you live before you think about storage, start here: Find your postcode
In this guide we will talk about kW, kWh, kWp, SEG, and DNO export limits (see Glossary) in plain English, with the practical decision logic you need before you let a quote bundle a battery in by default.
- Batteries help when you export a lot at midday and buy a lot back in the evening. They shift cheap (exported) solar into expensive (imported) evening use.
- Batteries are weak when you already have high daytime use (work-from-home, EV charging at lunch, heat pump strategy) because you are already capturing the “good” kWh without paying for storage.
- The core test is simple: Do you regularly have surplus solar to store, and do you have evening demand worth shifting into?
- Do not buy storage to “fix winter”. UK winter generation is low. A battery cannot create energy, only shift it.
- Do not buy storage to “future-proof” without a plan. If an EV or heat pump is coming, decide whether it will be a daytime load (good for solar) or an evening load (more battery-relevant).
Assumptions and variability
- We assume a typical UK home where electricity use is often higher in the morning and evening than at midday.
- We assume you are comparing a self-used kWh (avoids import) with an exported kWh paid under SEG (see Glossary).
- We assume the battery is primarily used for solar shifting (charging from solar and discharging later), not for arbitrage on smart tariffs.
- What varies most in real homes: occupancy patterns, base load, cooking habits, EV charging flexibility, and whether hot water or space heating can be shifted into sunny hours.
- We do not assume a specific electricity tariff or SEG rate because prices change. The decision structure is stable.
- For how SolarByPostcode estimates output and savings by outcode, see: Data sources and methodology
What a home battery actually does (and what it does not)
A battery does one job: move electricity in time.
- It can store surplus solar from midday and let you use it in the evening.
- It can smooth your import profile.
- It can increase your self-use percentage.
It cannot:
- improve your roof’s solar potential
- fix shading or poor roof geometry
- make winter solar “feel like summer”
- turn a low-usage household into a high-savings household
If the sales pitch is “you’ll use all your solar”, treat that as a red flag. In the UK, winter exists.
The simplest money model: “two prices” (import vs export)
You do not need perfect numbers. You need the logic:
- A self-used kWh is worth roughly your import unit rate avoided.
- An exported kWh is worth your SEG export rate.
These are usually not equal, so the economic question becomes:
Will the battery turn exported (lower-value) kWh into self-used (higher-value) kWh?
If you want to anchor your solar generation potential locally first, run your outcode page and come back:
The first diagnostic: do you actually have surplus to store?
If you already have solar, check your monitoring:
- On a bright day, do you see long periods where generation is higher than your home load?
- Do you export meaningfully around late morning to mid-afternoon?
If you do not have solar yet, you can still reason about it:
- Daytime-heavy home (work-from-home, EV can charge at lunch, flexible hot water): you will likely self-use a decent share already.
- Evening-heavy home (away 09:00–17:00, cooking and laundry evenings): you will likely export more and buy back more.
This is why batteries are not “standard kit”. They are household-pattern dependent.
Who batteries make sense for (and who should skip them)
If you want the most important “timing mismatch” foundation behind this, start with the flagship guide in this cluster:
The three levers that decide battery value
A battery’s payback is driven by a small set of levers. Get these right and the decision becomes much clearer.
If you are unsure what export limits are in your area, read:
A practical “do I need a battery?” checklist
You can do this without any spreadsheets.
Step 1: check your usage shape
If your home is naturally evening-heavy, batteries have a reason to exist.
If your home already runs meaningful loads at midday, a battery might be solving a problem you do not have.
If you have not looked at your usage patterns yet, start here:
- How much electricity does the average UK home actually use?
- Daytime vs evening electricity use: why self-use matters more than kWp
Step 2: check if you will have surplus solar to store
If you are designing a new system, “surplus” depends on system size, roof constraints, and household demand.
If you are already close to using most of your midday generation, the battery’s job is small.
Sizing context:
- Solar system sizing in the UK: choosing the right kWp without wasting money
- Oversizing your solar system in the UK: when it pays off and when it does not
Step 3: sanity-check the sales story
Be careful of these claims:
- “You’ll use all your solar now”
- “This makes you independent”
- “It fixes winter”
- “Everyone is doing it”
A battery can be sensible. It is just not universal.
How big should a battery be?
There is no “standard” battery size that fits every home. The right answer is usually:
- big enough to shift your common midday surplus into your common evening demand
- not so big that it sits under-used most days
A useful way to think about it is: you want the battery to do real work often, not be a trophy.
If you want to understand what “real work often” means, it helps to know why panels rarely hit their rating and why the usable shape of generation matters:
Batteries, inverters, and quote bundles
Installers often quote solar + battery + inverter as one package. That is fine, but you should still understand what each part is doing.
If you want the plain-English inverter mental model:
A “hybrid inverter” can be a good choice if you are likely to add a battery later. That is different from saying you should buy the battery now.
What about smart tariffs and charging from the grid?
Some households use batteries for tariff arbitrage: charge cheap at night, discharge in the evening.
That can work, but it is a different decision from “battery for solar”.
If you do not have a strong reason to run tariff arbitrage, keep the decision focused:
- Do you have midday surplus solar?
- Do you have evening demand?
- Is the import-export gap big enough for the battery to earn its keep?
If you want to quantify your local solar payback environment, these insights help:
Bottom line
A UK home battery is not a solar upgrade. It is a timing upgrade.
Buy one when you have:
- regular midday surplus
- regular evening demand
- an import vs export gap worth exploiting
Skip it (or delay it) when:
- your daytime self-use is already strong
- you can add flexible loads first (timers, EV smart charging, hot water control)
- you are trying to “fix winter” or “get off-grid”
Next reads
- Self-consumption vs export in UK solar: how the Smart Export Guarantee changes the maths
- How big should a home battery be? Avoiding the most common sizing mistake
- Winter solar generation in the UK: why batteries can’t fix seasonality
- Daytime vs evening electricity use: why timing matters more than totals
- Solar payback periods in the UK: what actually drives the number