Content status: Under review
This report sets out guidance rather than a dated dataset. Check the figures against the current price cap before acting on them.
See the current research and figuresExecutive summary
Fixing your energy tariff trades flexibility for certainty. This guide explains how fixed and variable tariffs work under Ofgem's price cap for households in England, Scotland and Wales, and how to think about the decision.
PowerGuardian does not currently publish a verified live comparison of specific fixed tariffs. Tariffs change frequently — you must check current offers directly with each supplier before switching.
Ofgem's household energy price cap applies in England, Scotland and Wales. Northern Ireland has a separate energy market and regulatory arrangements — the framing in this guide does not apply there.
Key findings
- A fixed tariff is protection against price rises, not a guaranteed saving.
- Exit fees, standing charges and any conditional incentives all shape the true cost of a fixed deal.
- The default comparison should be against the ongoing annual cost before any one-off incentives or credits.
- Because tariffs move often, any comparison table anywhere ages quickly — always confirm with the supplier before you switch.
How the two tariff types differ
A variable tariff tracks the market, typically constrained by Ofgem's quarterly price cap in England, Scotland and Wales. A fixed tariff locks your unit rate and standing charge for a set term, usually 12 or 24 months.
Which is better in retrospect depends entirely on how prices moved over the term. It cannot be known in advance.
How to compare fixed deals responsibly
Always compare the ongoing annual cost — unit rate plus standing charge at typical usage — before conditional credits or sign-up bonuses. A one-off incentive can flatter a tariff that is more expensive across the term.
Include any exit fee in your cost of exit if you might switch again soon, and check whether the fix protects both fuels or only one.
Why we don't publish a live cheapest-fix ranking here
A responsible ranking needs verified, dated, supplier-attributed evidence for every tariff shown: exact tariff name, unit rate, standing charge, region, payment method, VAT treatment, fixed term, exit fee, incentive treatment, tariff-data date, source and checked date.
Until we hold that evidence for every tariff we would list, we don't publish a public 'best fixed tariff' or 'cheapest fix' table here. When we do, it will be on the tariff-tracking pages, not backdated into this guide.
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Methodology
- This report is presented as general guidance. It does not name specific tariffs or claim a current market ranking, because we do not currently hold verified live tariff records for every supplier we would need to compare.
- Where PowerGuardian does publish tariff comparisons elsewhere, the default ranking is ongoing annual cost before conditional incentives, using Ofgem Typical Domestic Consumption Values.
Sources & references
- Ofgem — Energy price cap — UK regulator's quarterly price cap announcements
- Ofgem — Typical Domestic Consumption Values — Standard usage assumptions for UK households
- DESNZ — UK energy statistics — Department for Energy Security & Net Zero
Figures are checked against primary sources before publication. See our methodology for details.
Editorial note
PowerGuardian publishes independent, UK-focused research, analysis and commentary on household energy costs. Confirmed data, our own estimates, forecasts and scenarios are labelled separately so you can see which is which.
This report is reviewed at each Ofgem price cap announcement and whenever a source dataset it relies on is revised. It was last reviewed on 23 July 2026.
We take no commission from energy suppliers for the rankings, scores or figures shown here.
Read our editorial policy and corrections policy.
