How much electricity does a UK home use per day?
The average UK home uses approximately 8–10kWh of electricity per day, equivalent to around 2,900–3,600kWh per year. This varies significantly by household size, heating type, and whether you charge an electric vehicle at home.
| Household type | Typical daily usage | Annual usage |
|---|---|---|
| 1–2 bed flat, 1–2 people | 4–7 kWh | 1,500–2,500 kWh |
| 3 bed house, 2–3 people | 8–10 kWh | 2,900–3,600 kWh |
| 4+ bed house, 4+ people | 10–15 kWh | 3,600–5,500 kWh |
| Home with EV (add to above) | +7–10 kWh | +2,500–3,600 kWh |
| Home with heat pump (add to above) | +8–20 kWh (seasonal) | +3,000–7,000 kWh |
Your actual usage is the most important input for sizing. Check your smart meter or your energy supplier's app for your real daily consumption figures. Annual averages can be misleading because usage varies by season – winter evenings use more electricity than summer.
Recommended battery sizes by home type
Small flat
1–2 bedrooms, 1–2 occupants, low daily usage
Average home
3 bedrooms, 2–3 occupants, typical usage patterns
Large home or EV
4+ bedrooms, EV charging, or high evening demand
Does battery size affect savings?
Yes, but bigger is not always better. An oversized battery leaves unused capacity sitting idle every day, increasing your upfront cost without proportional savings. An undersized battery means you still draw from the grid at peak rates. The ideal battery covers your peak-hour consumption – typically the evening period from 4pm to 11pm – without significant excess.
The oversizing trap
A common mistake is buying the largest battery available on the assumption that more storage equals more savings. In practice, if your home uses 8kWh during peak hours and you install a 15kWh battery, that extra 7kWh of capacity costs you money upfront but generates no additional savings. It sits unused every cycle.
The exception is if you plan to add solar panels later. In that case, a slightly larger battery can store more surplus solar generation during the day, improving self-consumption. But for a grid-only setup, match the battery to your actual peak-period usage.
How to check your actual electricity usage
The most reliable way to size a battery is to look at your real consumption data. Here is how to find it:
Smart meter in-home display: Most smart meters show your daily and half-hourly consumption. Look at the data for a typical weekday – particularly the evening peak between 4pm and 10pm. That evening usage figure is the most relevant number for battery sizing.
Energy supplier app: Most UK energy suppliers – including Octopus, British Gas, E.ON, EDF, and OVO – provide half-hourly usage data through their app or online account. Download your usage data for the last month and look at the average daily consumption.
Annual bill: If you do not have a smart meter, your annual bill shows total kWh consumed. Divide by 365 to get a rough daily average. This is less precise but gives a starting point.
What about depth of discharge?
Depth of discharge (DoD) is the percentage of a battery's total capacity that is actually usable. Modern lithium iron phosphate (LiFePO4) batteries typically offer 90–100% DoD, meaning a 10kWh battery delivers 9–10kWh of usable energy. Older lithium-ion chemistries may only offer 80–90% DoD. When comparing batteries, check the usable capacity, not just the total capacity.
A battery advertised as 10kWh with 100% DoD delivers 10kWh of usable storage. A battery advertised as 10kWh with 80% DoD delivers only 8kWh of usable storage. The second battery effectively costs more per usable kWh, even if the sticker price is lower.
Battery sizing with solar panels
If you have solar panels, battery sizing works differently. The battery needs to capture surplus solar generation during the day and release it in the evening. The right size depends on how much excess solar your panels produce – which in turn depends on panel capacity, roof orientation, and the season.
As a general rule for UK solar homes: your battery capacity in kWh should be roughly equal to your solar array capacity in kWp. A 4kWp solar array pairs well with a 4–5kWh battery. A 6kWp array pairs with a 6–8kWh battery. If you also want to use time-of-use tariff arbitrage alongside solar storage, add 3–5kWh to that figure.
What Habo recommends
For most UK homes without solar panels, we recommend a 10kWh all-in-one battery system. This covers the evening peak consumption of a typical three-bedroom house, fits comfortably within G98 notification limits (our units use sub-3.6kW inverters), and delivers a payback period of approximately 3–5 years on a time-of-use tariff.
If you live in a smaller property or have lower-than-average usage, a 5kWh unit may be sufficient. If you charge an EV at home or have a heat pump, consider 12–15kWh.
Not sure what size you need?
Join the Habo waitlist and we'll help you work out the right battery for your home.
Join the waitlist