Cheapest electricity tariff for home battery (UK guide)

Key takeaways

• Battery-only households (no solar): focus on cheap off-peak import and manageable standing charge.
• Solar + battery: compare import and export. A higher export rate can beat a slightly cheaper overnight rate.
• Watch for constraints: some tariffs require a compatible smart meter, half-hourly data, direct debit, or specific hardware.
• Don’t compare on one unit rate: check peak rate, off-peak window, standing charge, and any exit fees.

Quick self-check

Do you have a smart meter?

Many battery-optimised tariffs need smart/half-hourly readings.

Do you export solar?

If yes, export rate and SEG eligibility matter.

Can you shift usage away from peak?

If not, a tariff with a very high peak rate may cost more overall.

Scenario A: Battery-only (no solar)

• Household use: 3,600 kWh/year electricity
• Battery: 10 kWh usable; charge/discharge round-trip efficiency assumed 90%
• Shiftable energy: 5 kWh/night charged off-peak on 250 nights = 1,250 kWh charged
• Delivered from battery: 1,125 kWh/year (90% of 1,250)

Assumptions: you can reliably charge overnight; no export; savings depend on the off-peak vs peak/flat spread and your actual shifting.

Scenario B: Solar + battery (export matters)

• Household use: 4,200 kWh/year
• Solar generation: 3,200 kWh/year (typical range varies widely)
• Exported after battery use: 900 kWh/year

Assumptions: SEG export paid for measured export; eligibility and export rates vary; some suppliers require you to take import from them.

Who battery tariffs usually suit

• Homes that can shift charging to overnight/off-peak hours
• Solar + battery owners who can benefit from strong export terms
• Households with smart meters willing to share half-hourly data (where required)
• People comfortable with variable pricing windows (and checking the details)

Who they may not suit

• If you can’t avoid peak-time usage (and peak rates are significantly higher)
• If you don’t have (or can’t get) a smart meter needed for the tariff
• If your battery is small and can’t cover peak periods reliably
• If you need predictable bills and prefer a simple flat rate

1) Standing charge wipes out savings

If a tariff has a higher daily standing charge, it can cancel out cheaper overnight rates—especially for lower-usage homes or flats.

2) Off-peak window is too short

If you can only charge for a few hours, a larger battery may not fill enough to cover peak times—depending on your charger power (kW) and settings.

3) Peak rates are materially higher

A low off-peak rate can come with a high peak rate. If you still import at peak (e.g., cooking, electric showers, heat pumps), bills can rise.

4) Smart meter & half-hourly data requirements

Many tariffs require smart meter readings and consent to half-hourly settlement data. If you’re on prepay or have a non-communicating meter, choices may be limited.

5) Export terms aren’t comparable

Export (SEG) can be paid monthly or quarterly; some deals require you to take import from the same supplier; eligibility often needs MCS documentation.

6) Exit fees and moving home

Fixed tariffs may have exit fees. If you move, the new occupier can’t usually “take over” your tariff unless the supplier supports it.

Do I need a smart meter for a battery tariff?

Often, yes. Many time-of-use tariffs require a smart meter capable of sending readings automatically, and some require half-hourly data. If you don’t have one, you can still compare tariffs, but your choices may be narrower.

Is Economy 7 still good for home batteries?

It can be, especially if you have a long off-peak period and can charge reliably overnight. But some Economy 7 deals have relatively high day rates or standing charges. It’s worth comparing against newer time-of-use tariffs in your region.

If I have solar + battery, should I prioritise export or off-peak import?

It depends on your surplus. If you export a meaningful amount, a higher SEG export rate can outweigh small differences in import pricing. If you export very little, import rates (and standing charge) tend to matter more.

Can I get paid to export electricity from my battery?

Some households export stored energy, but whether it’s worthwhile depends on tariff rules, export rates, and how your system is configured. Suppliers may have conditions on export payments and metering. Always check the specific export tariff terms.

Will switching tariff affect my SEG export payments?

It can. Some export tariffs require you to be an import customer with the same supplier; others don’t. If you switch import supplier, confirm whether you can keep your export arrangement or need to reapply.

Do home battery tariffs vary by UK region?

Yes. Unit rates and especially standing charges can vary by region (your local distribution network area). That’s why postcode-based comparisons are important when deciding what’s “cheapest”.

What if I’m on prepayment (prepay) electricity?

Battery-friendly time-of-use options may be limited on prepay and can depend on meter type. If you’re able to switch to direct debit, you may see more options—but only switch payment method if it suits your budgeting needs.

Could a “cheap overnight” tariff increase my bill?

Yes. If peak rates are high and you still import during peak (or your battery doesn’t cover it), the higher peak costs can outweigh off-peak savings. Compare using an estimated annual cost based on your realistic usage pattern.