A unit rate is what you pay (or earn) for one kilowatt-hour (kWh) of energy. On a UK electricity bill it is shown in pence per kWh. It is separate from the daily standing charge, which you pay whether you use electricity that day or not. Ofgem's price cap unit rates page publishes the capped average unit rates and standing charges for default tariffs each quarter.
What it means for a home battery
Battery savings are almost entirely a unit-rate story. You charge at the cheap off-peak unit rate and avoid buying at the expensive peak unit rate. Habo's best-case homepage maths for a 5 kWh EcoFlow STREAM use Octopus Go 12M Fixed GO-FIX-12M-26-10-14: night 9.4p, day 35.293p to 39.3081p by region (Octopus API, checked 28 October 2026). Octopus Go needs an EV charged at the home Octopus supplies (Smart Tariffs terms 2.1.3). After an assumed 90% round-trip efficiency, each delivered daytime kWh saves roughly the day rate minus (night rate / 0.9).
On a single-rate default tariff under the Ofgem price cap, there is only one import unit rate, so that overnight gap disappears. Export unit rates are the other side of the ledger if you have solar; see export tariff and SEG. Standing charges still matter for the whole bill: Habo's guide is energy standing charges and home batteries. Bills on a multi-rate meter can show more than one electricity unit rate; match each rate to its time band before you plan a charge schedule. Plug your own unit rates into the calculator. Habo's offer is an electrician-wired EcoFlow STREAM from £2,499. Join the waitlist.
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Frequently asked questions
No. The unit rate is pence per kWh used or exported. The standing charge is a daily fixed amount regardless of how much you use.
Each band has its own unit rate, for example a night rate and a day rate. The battery saving is the gap between those rates after efficiency losses.
Best-case homepage maths for a 5 kWh EcoFlow STREAM use Octopus Go 12M Fixed GO-FIX-12M-26-10-14 on the Octopus API: 9.4p night and 35.293p to 39.3081p day, depending on region. Octopus Go needs an EV charged at home.
Simple battery, simple install
Electrician-wired EcoFlow STREAM from £2,499. Habo will try to serve anyone who registers in an area where we have an electrician. Nothing to pay today.
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