What the January price cap means for solar, and what it does not

The short answer

The 22 to 24 per cent rise dominating January's headlines describes the whole dual-fuel bill, and it is driven mainly by gas, which makes up just over half of a typical bill. Solar competes with a narrower figure: the electricity unit rate, currently 26.32p per kWh. Only one forecaster, Cornwall Insight, has published a fuel-by-fuel breakdown of its own January forecast, and under that breakdown the electricity unit rate rises by about 7.6 per cent, not 24 per cent. Nobody has published what the higher supplier forecasts would mean for electricity specifically.

What is actually confirmed right now

Ofgem's confirmed cap for 1 October to 31 December 2026 sets electricity at 26.32p per kWh and 54.83p a day standing charge, and gas at 7.97p per kWh and 29.68p a day, announced 26 August 2026. The typical dual-fuel Direct Debit bill on those rates is £1,723 a year. Nothing about January is confirmed yet: Ofgem announces the 1 January to 31 March 2027 cap around 25 November 2026, and every number below that date is a forecast. The confirmed figure, the previous quarter and the dated forecasts below all sit on one tracker page, kept current as each is announced.

The one dated fuel-by-fuel breakdown that exists

Cornwall Insight publishes its own forecast with a full electricity and gas split, last updated 23 September 2026. Under that forecast, the January to March 2027 cap comes out at an average £1,872.15 a year, using slightly different assumed household consumption than the current cap. The cleaner comparison, and the one that avoids mixing up a rate change with a consumption-assumption change, is the unit rates and standing charges side by side.

Cornwall Insight, forecast last updated 23 September 2026. The forecast's own typical-bill figure of £1,872.15 is built on different assumed household consumption than the current 1 October to 31 December 2026 cap, so comparing the two headline totals directly mixes a rate change with a consumption-assumption change. The unit rates and standing charges above are the like-for-like comparison.

On the rates alone, gas rises around twice as fast as electricity in Cornwall Insight's own forecast, consistent with gas being the dominant driver of every cap move this year, including October's: press synthesis of Ofgem's own October figures put the gas component of that rise at roughly eight per cent against under one per cent for electricity-only households, dated 26 August 2026.

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What this means for solar payback specifically

Solar competes with the unit rate, not the whole bill. Every kWh a system generates and a household uses itself displaces a kWh that would otherwise cost 26.32p today. Under Cornwall Insight's own January forecast, that figure moves to 28.33p, a real increase in the value of self-consumption, worth having, but a fraction of the 23 to 26 per cent figure making headlines. Standing charges do not move with generation at all: at 54.83p a day, that is £200.13 a year paid whether a single panel is on the roof or not, and none of the four January forecasts move the standing charge by more than a few pence.

Export income moves separately again, set commercially by suppliers rather than by Ofgem's cap, so a bigger cap has no direct effect on what an export tariff pays. The full mechanics of how self-consumption, export and standing charges combine into a payback figure are worked through in our guide to the price cap explained, and solar payback.

A worked example, both ways

Take a household self-consuming 2,000 kWh of solar generation a year, the kind of figure a modest domestic system produces. At 26.32p, that displaces £526.40 of imported electricity today. Under Cornwall Insight's own January forecast of 28.33p, the same 2,000 kWh displaces £566.60, a gain of £40.20 a year, about 7.6 per cent, exactly matching the rate change because standing charges are essentially untouched. That is the honest scale of what the January cap does to a solar payback sum, under the one forecast that actually publishes the number. It is not nothing, and it is not the quarter of a bill the headlines describe.

Why the whole-bill number gets quoted instead

Because it is the bigger, more newsworthy figure, and because most coverage of the price cap is written for the general reader paying a whole dual-fuel bill, not specifically for someone with solar on the roof. That is a fair choice for a general audience and a misleading one for a solar payback sum, which is exactly the gap this guide exists to close.

• Read 22 to 24 per cent as the whole gas-led bill, not as what solar displaces.
• Use 26.32p today, and Cornwall Insight's 28.33p as the one sourced forecast figure, not the headline percentage, when modelling a January payback sum.
• Treat any electricity-only figure beyond Cornwall Insight's own as illustrative, because no other forecaster publishes the split.
• Re-run the sum once Ofgem confirms, around 25 November 2026, since every number above is a forecast until then.

What to do while the real number is still two months away

Because unit rates, and therefore payback, vary by region and by household, the version of this arithmetic that matters is the local one. Every county page across our coverage area runs a calculator on the same model, and our solar guide covers the generation side of the sum.