Step 1 — Find your daily usage (kWh)
Check your electricity bill (or smart meter app) for your typical usage. As a reference point, Ofgem estimates a typical household uses around 2,700 kWh of electricity per year (roughly 7–8 kWh per day).
Step 2 — Choose your goal (this sets the size)
Pick the outcome you want most:
Maximise solar self-use: aim to store enough to cover your evening/overnight usage when solar isn’t generating.
Shift usage on time-of-use tariffs (no solar): size to cover your peak-price hours (typically late afternoon to bedtime).
Future-proof for EV / bigger loads: allow extra headroom if you’re adding EV charging or other upgrades later.
Step 3 — Quick sizing guide (most homes)
Use this as a simple starting point, then fine-tune based on your actual usage pattern:
1–2 bedroom / lower usage: 3–5 kWh
Typical 3-bed home: 5–10 kWh
Larger homes / higher usage or EV plans: 10–15 kWh
A practical rule that works in real homes
A good rule of thumb is to size your battery so it can cover the electricity you actually want to use later (most commonly evening + overnight), rather than trying to store your entire day’s usage.
Important note (usable vs. labelled capacity)
Battery “kWh” ratings can include usable capacity limits (battery protection settings). That’s why we confirm your usage profile and goals during the survey before recommending the final capacity.