This is runtime, not lifespan. Runtime is how many hours a full charge lasts. Lifespan is how many years the battery keeps working. For the years figure, see how long does a home battery last.
How long 10kWh lasts in a typical home
A medium UK home uses about 7 to 10kWh of electricity a day. That figure comes from Ofgem consumption data and the Energy Saving Trust. A 10kWh battery, giving around 9kWh usable, covers most of that day.
In practice that means overnight plus most of the next day, as long as you are not running heavy electric loads back to back. Charge it on cheap night rates or from solar, and the house runs on stored power while grid prices peak.
The catch is short bursts of high power. A kettle, an oven or an electric shower pulls a huge draw for a few minutes. Those minutes eat into the battery far faster than lights or a fridge ever will.
Runtime by appliance
The table below shows how long a full 10kWh battery, about 9kWh usable, runs common appliances on their own. These are continuous run times. Most appliances switch on and off through the day, so real use spreads the load out.
| Appliance | Typical power draw | Runtime from ~9kWh |
|---|---|---|
| Wifi router | 10W | around 5 weeks |
| LED lighting (whole house) | 55W | around 7 days |
| Fridge freezer (compressor running) | 100W | around 3.5 days |
| Television | 100W | around 3.5 days |
| Washing machine (heating) | 2,000W | around 4.5 hours |
| Electric oven | 2,000W | around 4.5 hours |
| Air source heat pump | 2,500W | around 3.5 hours |
| Electric shower | 9,000W | around 1 hour |
An electric shower can use more energy in ten minutes than your fridge uses all day. That is why two homes with the same battery can see very different runtime.
What changes the number
Three things move the answer most.
Heating is the big one. A home with gas heating uses far less electricity than an all electric or heat pump home. In winter a heat pump alone can pull 20kWh or more a day, so a 10kWh battery becomes a top up, not a full day of cover.
Household size matters too. A one bed flat might sip 4 to 5kWh a day and stretch a 10kWh battery across a day and a half. A busy family home with cooking, laundry and electric hobs can clear 10kWh before bedtime.
Then there is how you use it. Backup only use, held in reserve for a power cut, lasts far longer than daily cycling.
How we size a battery to your house
A number on a website is only ever a guide. We size the battery to your actual usage, not the other way round.
At survey we look at your consumption, your supply and your space, then talk through what makes sense. We are not tied to one manufacturer, so the recommendation fits your home rather than our stockroom. Most home installs are done in a day. See how battery storage installation works from survey to handover.
