Fixed Energy Tariff Facts (UK): What to Know Before You Fix

Thinking about locking in your gas and electricity unit rates? This guide explains how fixed energy tariffs work in the UK, the benefits and risks, how they relate to the Ofgem price cap, and what to check before you switch—so you can decide with confidence.

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Key takeaways

A fixed tariff locks your per-unit price (kWh) and usually the standing charge for a set term (e.g., 12 or 24 months). Your bill can still change with usage.
Fixed tariffs are not controlled by the Ofgem price cap once you sign. The cap mainly applies to Standard Variable Tariffs (SVTs), not fixed deals.
Pros: budget certainty, protection if wholesale prices rise. Cons: exit fees, you won’t benefit if market prices fall.
You get a 14-day cooling-off period from contract start. Within the last 49 days of a fixed deal, exit fees should not apply if you switch at the end of term.
Always read the Tariff Information Label (TIL): unit rates, standing charges, exit fees, payment method, contract length, and any pass-through clauses.

What is a fixed energy tariff?

A fixed energy tariff sets the price you pay per kilowatt hour (kWh) for electricity and gas, and typically the standing charge, for a defined period (e.g., 12 or 24 months). While your unit prices are fixed for the term, your total bill can still vary based on how much energy you use.

Unit rate: the price per kWh of electricity and/or gas.
Standing charge: a daily fee to cover network costs and other fixed costs.
VAT: domestic energy is usually charged at 5% VAT.

Fixed tariffs can offer peace of mind if you want predictable pricing and protection against potential price rises during your contract.

Fixed vs variable vs tracker tariffs

There are three common types of domestic tariffs in the UK:

Tariff type	How pricing works	Upsides	Considerations
Fixed	Unit rates and usually standing charges are locked for the term.	Budget certainty; protection if market prices rise.	Exit fees may apply; you miss savings if prices fall.
Standard Variable (SVT)	Rates can change; typically aligned with the Ofgem price cap.	No fixed-term exit fees; benefit if prices fall.	Less certainty; rates can rise at cap changes.
Tracker/Time-of-Use	Rates vary with wholesale or by time (e.g., off-peak EV tariffs).	Potential savings with flexible usage.	More complex; may need a smart meter and careful management.

How the Ofgem price cap fits in

The Ofgem price cap limits the typical unit rates and standing charges suppliers can charge customers on Standard Variable Tariffs. It is reviewed quarterly. The cap is not a cap on your total bill—what you pay still depends on how much energy you use.

Fixed deals are not governed by the price cap once you sign the contract. Always compare the fixed deal’s unit rates and standing charges against current SVT rates to decide whether fixing offers value for you.

Benefits and risks of fixing your energy tariff

Benefits

Predictable unit rates for 12–24 months
Protection from future wholesale price rises
Helps with budgeting and cash-flow planning
Some deals include rewards or green options

Considerations

Exit fees if you leave early (check amounts)
No automatic benefit if market prices fall
Terms vary by supplier (read the small print)
Fixed rates can be higher than SVT at the time you sign

Exit fees, terms and cooling-off

Exit fees: Many fixed tariffs charge an early exit fee per fuel if you leave before the end date. Amounts vary by supplier; always check your Tariff Information Label (TIL).
Cooling-off period: You normally have 14 days from the contract start to cancel without exit fees. You may still pay for any energy used during that time.
49-day rule: Suppliers should not charge exit fees if you switch within the final 49 days of a fixed term and the switch completes at (or after) the end of the contract.
Mid-contract changes: Fixed deals generally can’t increase unit rates during the term except for clearly stated pass-through items (e.g., VAT changes, certain government or network charges). Check your terms.

Who might consider fixing?

Fixing can suit households that:

Value price certainty and easier budgeting
Expect to use a steady or higher-than-average amount of energy
Prefer to avoid quarterly SVT changes linked to the price cap
Can commit to a 12–24 month term and are comfortable with possible exit fees

It may be less suitable if you expect to move soon, want maximum flexibility, or think prices might fall significantly.

What to check before you fix

Compare like-for-like using the Tariff Information Label (TIL) and your annual usage (kWh) from recent bills or your online account:

Unit rates (p/kWh) for electricity and gas
Standing charges (p/day)
Contract length and end date
Exit fees per fuel and when they apply
Payment method (Direct Debit often has lower rates than pay-on-receipt)
Meter type (single rate, Economy 7/10, smart time-of-use)
Eligibility (smart meter requirement, region, credit checks)
Any pass-through clauses for regulated charges or VAT
Perks & green claims (REGOs, carbon offset—understand what’s included)

Tip: Use your actual annual consumption in kWh to estimate costs under each tariff. Avoid comparing only by monthly Direct Debit amounts, which can be adjusted.

How to switch to a fixed tariff

Gather your details: postcode, current supplier/tariff, and annual usage in kWh.
Compare deals: check unit rates, standing charges, exit fees, and term.
Apply online: complete the switch with your chosen supplier. Most switches complete in about 5 working days.
Cooling-off: you have 14 days to change your mind. Provide accurate opening meter readings to ensure correct billing.
Final bill: your old supplier sends a final bill after the switch based on the closing reading.

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Special cases and common questions

Smart meters and fixed tariffs

Many fixed tariffs work with any meter, but some require a smart meter—especially time-of-use or EV tariffs. If half-hourly data is requested, you can usually choose your data sharing preference in your account settings.

Prepayment meters

Fixed deals for prepayment customers are less common. If you’re on prepay, compare SVT rates and check whether any fixed prepay options are available to you.

Green fixed tariffs

Some fixed deals match your electricity with renewable certificates (REGOs) and may include carbon-offset gas. Review the supplier’s environmental claims to understand what is backed by certificates, offsets, or direct investment.

Moving home on a fixed deal

Tell your supplier before you move. You may be able to take your fixed tariff to your new address, or you might be placed on a deemed/out-of-contract rate until you choose a new tariff. Provide move-in and move-out meter readings.

Payment method and credit checks

Direct Debit is often cheaper than paying on receipt of bill. Some suppliers run a soft credit check for DD eligibility. You can usually change your DD amount based on usage and balance.

Support if you’re vulnerable or struggling

Ask about the Priority Services Register, Warm Home Discount (if eligible), and other support schemes. If you’re behind on bills, contact your supplier early to agree an affordable plan.

Quick example: estimating your annual cost

To estimate, multiply your annual usage by the unit rates and add standing charges:

Annual electricity cost ˜ (electricity kWh × p/kWh) + (standing charge p/day × 365) Annual gas cost ˜ (gas kWh × p/kWh) + (standing charge p/day × 365) Total (plus 5% VAT)

Compare that total against your current SVT projection to judge whether fixing offers value for your household.

Fixed energy tariff FAQs

What is a fixed energy tariff?

A fixed tariff locks your unit rates (and usually standing charge) for a set period. Your total bill still varies with usage.

Are fixed tariffs cheaper than the price cap?

Not automatically. Compare the fixed deal’s unit rates and standing charges against the current SVT rates to see which is better for your usage.

Can I leave a fixed tariff early?

Usually, yes—but an exit fee per fuel may apply unless you’re within the 14-day cooling-off period or the last 49 days of the term (and switching at contract end). Check your terms.

Does a fixed tariff include the standing charge?

Most fixed deals also fix the standing charge for the term, but always confirm in the Tariff Information Label.

Can my supplier increase prices on a fixed deal?

Generally no, except for clearly stated pass-through items like VAT changes or certain regulated charges. Your contract will specify any exceptions.

Do I need a smart meter?

Not for every fixed tariff. Some require it, especially time-of-use deals. If you have one, ensure you provide accurate readings or keep the meter in smart mode.

Is there a cap on fixed tariffs?

No. The Ofgem price cap applies mainly to SVTs, not fixed deals—so compare carefully before you commit.

Important information

This guide is for UK domestic energy customers and provides general information, not financial advice. Tariff availability, rates and regulations can change. Always check your supplier’s terms and the latest Ofgem guidance before you commit.

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