CONSIDERED HOME ENERGY TOOLKIT
How Much Could a Home Battery Save Me?
See what a battery could save by charging when electricity is cheap and using that stored energy when your normal electricity rate is higher.
✓ Takes less than a minute✓ Uses your own electricity rates✓ Shows whether a bigger battery would actually save more
A deliberately simple tariff-shifting estimate. It does not model solar generation, export income or smart-grid rewards. Those can add value, but keeping them separate makes it much easier to see what the battery itself is doing.
YOUR ELECTRICITY & BATTERY
Five figures to get started
Use the buttons if you're not sure where to find something.
Battery lifetime & advanced assumptions
YOUR ESTIMATE
Estimated annual saving ~£0£0/month · £0/day
~0% lower electricity unit cost
PAYBACK & RETURN
What does the saving mean against the battery cost?
Estimated payback—Across the entered warranty period
Average annual return—Average modelled annual saving ÷ installed cost
Projected-period return—Total modelled savings ÷ installed cost
What this suggests
Without tariff shifting£0/year
With the battery shifting energy£0/year
BATTERY SIZE
Would a bigger battery save more?
The useful saving should flatten once additional capacity is more than your entered daily use can make use of.
WARRANTY & DEGRADATION
How could the saving change over time?
This models degradation through the entered warranty and then continues the same trend for five additional indicative years. Electricity rates are held flat so you can see degradation rather than a price forecast.
Warranty is not the same as expected lifespan. The five years beyond warranty are an illustrative extension, not a prediction or guarantee of battery life.
POSSIBLE EXTRA VALUE
Your battery may be able to earn more
Some compatible home batteries can participate in flexibility or virtual power plant schemes, which may reward households for helping balance the grid. That income can vary and is not included in the savings above.
Important assumptions & caveats
This is an estimate, not a guaranteed saving. The lifetime projection extends five years beyond the entered warranty because a warranty is not the same as expected battery life. Those post-warranty years are indicative only and assume degradation continues at the same annual rate as during the warranty.
It assumes you can charge enough during the cheap-rate window and use the stored energy later instead of buying the same amount at your normal rate.
Real batteries also use a small amount of electricity themselves for controls, standby operation, heating/cooling and inverter electronics. Some of this may be reflected in real-world efficiency, but this tool does not separately model every auxiliary load.
Electricity prices and tariff structures change. The calculator holds the rates you enter constant, so future savings could be higher or lower. It also excludes solar generation, export payments, smart-grid/flexibility income, finance costs, servicing and replacement parts.
If you enter an installed cost, use the total price you would actually pay, including installation and any required electrical work. The payback shown is a simple comparison, not financial advice.