The tariff decides whether the hardware was worth it
A heat pump on the wrong tariff costs more to run than the boiler it replaced. Solar on the wrong export rate earns a fifth of what it should. This is the cheapest lever in the whole upgrade, and the one nobody sells you.
A day on a heat pump tariff
12.9p to 39.6p
- 00:00
- 06:00
- 12:00
- 18:00
- 23:00
- Cheap window
- Standard
- Evening peak
Spread on export rates
4.1p to 15.9p
Across 6 export products from one supplier
Octopus Go overnight rate
8.6p
Against 26.3p on a standard variable tariff
Electricity to gas ratio
3.3×
The number a heat pump has to beat
Products compared
31
Across the five guides below
Illustrative. The standard variable rate and the ratio are the Ofgem price cap for 1 October 2026 to 31 December 2026. The overnight rate is Octopus Go's on 17 September 2026, averaged over the fourteen regions. The export spread is Octopus's own range on 17 September 2026; other suppliers' rates are the published figures in the guide below.
The guides
Two meters, two guides
Electricity is where the money is, and where all four families of product live. Gas is a page about one decision: whether to keep paying for the meter at all. Export gets a page of its own, because it is the one tariff you can change without touching the one that bills you.
The day
The same 24 hours, priced three ways
Small multiples rather than one chart with three lines, because the point is the shape of each day rather than a comparison at any one hour. All three are on the same scale.
Standard variable
One rate all day. Nothing to optimise, nothing to get wrong.
Flat average across the day: 26.3p per kWh — which is why the average tells you nothing useful on its own.
EV overnight
One deep window while you sleep. The whole house benefits, not just the car.
Flat average across the day: 26.0p per kWh — which is why the average tells you nothing useful on its own.
Heat pump, three windows
Cheap before the house wakes, cheap mid-afternoon, expensive through the evening peak.
Flat average across the day: 23.5p per kWh — which is why the average tells you nothing useful on its own.
The standard variable day is the Ofgem price cap unit rate, GB average, for 1 October 2026 to 31 December 2026. The EV day is Octopus Go and the heat pump day Cosy Octopus, their published rates on 17 September 2026 averaged over the fourteen regions, each hour the mean of its two half hours.
What you'd pay
Four households, one year, both tariff shapes
Net cost is the number that matters: electricity bought, minus export income. The households that can move the most consumption gain the most, which is why the heat pump and EV case dwarfs the rest.
| Household | Standard | Smart tariff | Export income | Net change |
|---|---|---|---|---|
| EV, no solar3-bed semi, gas heating, 9,000 miles a yearThe clearest win on this page. Charging moves to the cheap window and nothing else has to change. | £1,180 | £780 | — | −£400 |
| Solar and battery, no EV4kW array, 5kWh battery, gas heatingThe battery charges on the cheap rate in winter and on the roof in summer. The export tariff matters more than the import one. | £940 | £610 | £290 | −£620 |
| Heat pump, no EV3-bed semi, air source heat pump, no solarWorth doing, but only with controls that will actually pre-heat. On a badly set up system the peak rate can cost more than the windows save. | £1,840 | £1,490 | — | −£350 |
| Heat pump, EV, solar and batteryThe full set, 4-bed detachedThe case where tariff choice is worth more per year than any single piece of hardware in the house. | £2,410 | £1,320 | £410 | −£1,500 |
Illustrative. Placeholder figures to show what this page will hold. Real ranges arrive with the quote and performance data behind them.
Traps
Six things that catch people out
None of these are hidden. They are all in the tariff information label, which is a document almost nobody reads before switching.
Where this page's answers come from
- Ofgem — default tariff cap level, and the Smart Export Guarantee tariff table
- Supplier published tariff information labels
- Elexon — half-hourly settlement status
Last checked against these sources on 17 September 2026.
The day rate pays for the night rate
A 7p overnight window usually comes with a day rate several pence above the standard variable rate. If your consumption does not actually move into the window, a smart tariff costs you money.
Export and import are separable
You can take your export tariff from one supplier and your import from another. Suppliers rarely mention this, and it is often worth more than switching either one alone.
Half-hourly settlement has to be on
A smart meter is not enough. It has to be reading half-hourly and the supplier has to have it in that mode, or the cheap window will not be applied.
Compatibility lists are shorter than they look
Intelligent and heat-pump-linked tariffs work through a specific list of cars, chargers and heat pump models. Check yours is on it before you switch, not after.
Rates get revised, not fixed
Most of these are variable products. The rate you signed up for is not a rate you keep, and there is usually no exit fee precisely because there is no promise.
A battery changes which tariff wins
Without storage the cheap window only helps what you use during it. With storage, the window fills the battery and the rest of the day runs off it, which is a different calculation entirely.
Questions
Common questions about tariffs
Do I need a smart meter?
For every time-of-use and export tariff on this site, yes, and it has to be reading half-hourly. That is the single most common reason a switch stalls: the meter is installed but still sending daily readings.
Which tariff should I look at first?
The one for the fuel you already buy. Get the electricity and gas side right, then add a specialist product for whatever you have installed — export for solar, an EV rate for a car, a heat pump rate for a heat pump.
Can I have more than one of these at once?
You have one import tariff per meter and, if you generate, one export tariff. The specialist products replace your electricity import tariff rather than sitting alongside it, and the export side can come from a different supplier entirely.
Is the Smart Export Guarantee the same as a feed-in tariff?
No. Feed-in tariffs closed to new applicants in 2019 and paid for generation as well as export, at much higher rates. The Smart Export Guarantee pays only for what you actually send back, at whatever rate your supplier offers.
Should I choose the tariff before or after the upgrade?
After. The right tariff depends on the consumption you will have rather than the consumption you had, and a fixed flat rate signed the month before an installation is the most reliable way to make the running costs disappointing.
How often should I check?
Twice a year is reasonable for import, and once a year for export. Export rates in particular have moved a long way since 2023, and nobody writes to tell you that a better one exists.
Work out which tariff suits your home
Start with your postcode. We'll use what is known about the property and what you have already installed.