When is the right time to switch heat pump tariff? Seasonal timing and price cap dates explained
The Ofgem price cap changes every quarter — April, July, October, January. Each change shifts the off-peak rates on every variable heat pump tariff in the UK. Understanding that cycle helps you switch at the right moment, avoid locking in at the wrong rate, and know when to check whether your current tariff is still competitive. This guide explains the timing, what to watch for, and why summer is often the best time to switch.
The quarterly price cap cycle
Ofgem sets the energy price cap four times a year, with each period running for three months:
| Period | Dates | When announced |
|---|---|---|
| Q1 | 1 January – 31 March | Late November |
| Q2 | 1 April – 30 June | Late February |
| Q3 | 1 July – 30 September | Late May |
| Q4 | 1 October – 31 December | Late August |
For heat pump owners on variable tariffs — which covers most dedicated heat pump tariffs including Cosy Octopus, EDF FreePhase, and E.ON Next Pumped — this matters directly. The cap sets the standard unit rate that most variable tariff prices are calculated as a percentage of. When the cap changes, so do your rates.
The current position (as of June 2026): The Q2 2026 cap of £1,641/year set the standard electricity rate at 24.7p/kWh. From 1 July 2026, the Q3 cap rises 13% to £1,862/year — meaning standard electricity rates will increase to approximately 27–28p/kWh from that date. Ofgem's Q4 forecast currently points to a modest further movement to around £1,826–£1,899/year.
How the cap cycle affects your decision
Variable tariffs: rates change with each cap
Most heat pump tariffs are variable — there's no exit fee, but the rates adjust every quarter. The structure (cheap windows, peak hours, percentage discount) typically stays fixed; what changes is the underlying rate the percentages apply to.
This means:
- When the cap rises, your cheap-window rate and peak rate both rise proportionally.
- The saving relative to the standard cap usually stays the same; your absolute bill goes up.
- You don't need to re-evaluate your tariff choice every quarter, but you should know when a cap change is coming.
Fixed tariffs: lock in now vs wait
A fixed tariff sets your unit rate for the term regardless of cap changes. With the Q3 cap rising 13% in July 2026, a fixed tariff taken out before 1 July locks in Q2-era rates through winter — which is when your heat pump does most of its work.
As of June 2026, some fixed deals are available below the projected winter cap level. Whether that makes sense depends on how long the fix runs, any exit fees, and your confidence in cap forecasts. Cornwall Insight, whose forecasts have historically been accurate, expected Q4 2026 to come in around £1,899/year — above the Q3 level.
The general rule: if forecasts point to rising cap levels for the next two to three quarters, a fixed tariff is worth evaluating. If they point to falling prices, staying variable is usually better.
Why summer is often the best time to switch
The best time to review and switch your tariff is spring or early summer, for three reasons:
1. You have winter data. If you've been on a heat pump tariff through winter, you now have six months of real half-hourly consumption data. You can see exactly how much electricity you used at each rate band and calculate what you'd have paid on a different tariff. Comparing against a summer snapshot is much less informative — heat pump consumption is a fraction of winter levels.
2. Switching before summer means you're settled before winter. Most suppliers take two to three weeks from application to meter enrolment on the new tariff. If you decide to switch in October when bills start climbing, you may spend several weeks on your old tariff into the expensive season.
3. Summer rates are lower on most variable tariffs. If you're moving to a tariff with a peak-rate risk (Cosy Octopus's 16:00–19:00 window, for example), summer is a low-stakes period to get used to managing your consumption around it. You can establish the scheduling habits before the stakes are higher.
The worst time to switch
Mid-winter (December–February) is the least informative time to evaluate a tariff switch. Your heat pump is at peak consumption, bills are high, and it's tempting to make reactive decisions based on one expensive month rather than annual averages. It's also when switching admin takes the most time relative to the benefit.
Immediately before a cap change can also be awkward. If you're switching supplier and the cap rises mid-process, your new tariff enrolment may land at the new (higher) rate. Check the Q3 start date (1 July) if you're switching in June.
What about exit fees?
Most variable heat pump tariffs have no exit fee — you can leave at any time. The main exceptions are fixed tariffs, where exit fees are common (typically £25–£50 per fuel). Cosy Octopus moved to a six-month fixed structure with a £25 exit fee from March 2026. EDF FreePhase and E.ON Next Pumped remain no-exit-fee variable tariffs.
If you're on a fixed tariff, check your exit fee against the savings available on a switch before acting. On a short remaining term, it's usually not worth paying the fee.
A practical switching checklist
Before switching, confirm:
- Smart meter status — is it SMETS2 and sending half-hourly data to your supplier? Most heat pump tariffs require this. SMETS1 meters enrolled with DCC also qualify.
- Your current tariff's exit fee — none on most variable tariffs; check if you're on a fix.
- Your DNO region — rates vary by region. Use your postcode to find your region if you're unsure; the Heat Pump Tariffs comparison tool does this automatically.
- What you actually used last winter — download or view your half-hourly data via Bright before switching, so you can compare tariffs against real consumption rather than estimates.
- The switch timeline — apply at least three weeks before you want the new tariff active, especially if switching before the July cap change.
Checking whether your current tariff is still the best fit
You don't need to switch constantly. But it's worth a review:
- After each winter — to evaluate whether the tariff delivered the savings you expected.
- Before each Q3 (July cap change) — the biggest annual cap movement is usually in summer; this is when fixed deals can look attractive.
- When a new tariff launches — the heat pump tariff market has expanded considerably in 2025–26 (British Gas Heat Power, ScottishPower Heat Pump Saver, E.ON Next Pumped all launched or revised recently). A tariff that wasn't available when you last looked may be competitive now.
Run a comparison on Heat Pump Tariffs using your real half-hourly data — it's the only way to know which tariff wins for your actual usage pattern, not a national average.
The short version
- The price cap changes quarterly: April, July, October, January. Variable tariff rates move with it.
- The Q3 2026 cap rises 13% from 1 July — a meaningful increase if you're on a variable tariff.
- Review and switch in spring or early summer: you have winter data, you beat the cap rise, and you have time to settle before winter.
- Most heat pump tariffs have no exit fee — switching is low-risk.
- A fixed tariff can make sense when cap forecasts point upward. Check exit fees before committing.
- Compare against your real usage data, not national averages.
Compare every UK heat pump tariff against your real half-hourly usage on Heat Pump Tariffs — takes about two minutes if your Bright account is connected.