How to Compare UK Gas and Electricity Tariffs in 2025

Why comparing tariffs matters in 2025

After several years of volatile wholesale prices, supplier failures and the ongoing Ofgem energy price cap, 2025 is another crucial year to stay on top of your home energy deal. Many UK households are still on standard variable or default tariffs, which can be among the most expensive options.

By actively comparing gas and electricity tariffs, you can:

• Identify cheaper fixed-rate deals when they become available.
• Avoid overpaying on standard variable tariffs that track the price cap but may not be the best value for your usage.
• Choose tariffs that match your lifestyle — such as off-peak, smart meter, or green energy plans.
• Gain visibility on your standing charges, unit rates and exit fees before you commit.

Even a modest saving of £10–£20 per month adds up to hundreds of pounds over the life of a tariff, making comparison an essential part of managing your household budget.

What you need before you compare energy tariffs

You don't need to be an energy expert to compare tariffs effectively. Having the following information ready will help you get accurate, personalised results:

If anything is missing, you can still compare using estimates, but exact usage data will always produce the most reliable results.

Key tariff terms explained: unit rate, standing charge & more

Comparing tariffs is easier when you understand the core pricing elements. Here are the main terms you'll see in 2025:

Unit rate (price per kWh)

This is the amount you pay for each kilowatt hour (kWh) of gas or electricity you actually use. It's usually shown in pence per kWh (e.g. 28p/kWh). Lower unit rates mean you pay less for every unit of energy consumed.

Standing charge

A daily fixed fee, charged whether or not you use any energy. It covers the cost of maintaining the network, meter readings, and other fixed infrastructure. In 2025, standing charges can vary significantly between suppliers and regions, so they're an important part of your comparison.

Tariff type

• Fixed-rate tariff: Unit rates and standing charges are locked for a set term (e.g. 12 or 24 months). Your monthly payments can still change if your usage changes, but the price per kWh won't.
• Standard variable tariff (SVT): Prices can go up or down, often following the Ofgem price cap. Good for flexibility, but not always the cheapest in the long run.
• Time-of-use / off-peak tariffs: Different rates at different times of day, usually paired with a smart meter. These can be attractive if you can shift usage to off-peak periods.

Exit fees

Some fixed tariffs charge an exit fee if you leave before the end of your contract. In 2025, many suppliers are offering more flexible fixed plans, but always check for exit fees before switching.

Payment method

Paying by monthly Direct Debit usually unlocks lower rates compared to paying on receipt of bill or prepayment meters. When you compare, make sure you select the payment method you actually use.

Step-by-step: how to compare gas and electricity tariffs in 2025

Follow these steps to compare tariffs confidently and avoid common pitfalls:

1. Gather your details

   Find your latest bill and note your postcode, current supplier, tariff name, meter type and annual kWh usage for both gas and electricity.

2. Decide what matters most

   Is your priority the lowest price, green energy, price certainty, or flexibility (no exit fees)? Clarifying this helps you pick between fixed and variable options.

3. Compare unit rates and standing charges together

   Don't just chase the lowest unit rate or the lowest standing charge in isolation. A low unit rate with a very high standing charge could cost more overall if your usage is low, and vice versa.

4. Use your actual kWh usage for accuracy

   When you input your annual usage, comparison tools can estimate your total yearly cost for each tariff, letting you see side-by-side savings versus your current deal.

5. Check the contract length and exit fees

   Look for any minimum term, early exit charges, or special conditions (such as requiring a smart meter installation).

6. Review payment method and billing options

   Confirm whether the price assumes Direct Debit, online billing or paper bills. Some tariffs are only available for online management.

7. Check eligibility rules

   Some of the best deals may have eligibility criteria, such as being a new customer, installing a smart meter, or living in certain regions.

8. Calculate realistic savings

   Look beyond headline “up to” figures. Compare the estimated annual cost of each tariff against what you currently pay. This gives a clear, like-for-like saving.

9. Start the switch

   Once you've chosen a tariff, you can start the switch online. You won't experience any supply interruption; only your billing company changes.

Fixed vs variable tariffs in 2025: which is better?

There is no one-size-fits-all answer, but you can choose more confidently by understanding the trade-offs.

In 2025, many households choose a mix of comfort and flexibility: switching from expensive legacy SVTs to competitive short-term fixes, then reviewing options again when the fix ends.

Comparing dual fuel vs single fuel tariffs

Most UK homes use both gas and electricity. You can either buy them from the same supplier (dual fuel) or from different suppliers.

Dual fuel tariffs

• One supplier, one bill for both gas and electricity.
• Sometimes offer dual fuel discounts or simpler account management.
• Easy switching process with a single point of contact.

Single fuel tariffs

• Separate suppliers for gas and electricity.
• Occasionally cheaper if one supplier has a market-leading rate for only one fuel.
• More admin: two accounts, two sets of communications.

When comparing in 2025, don't assume dual fuel is always cheapest. Check the combined annual cost of dual fuel against the total cost of separate gas and electricity tariffs.

Smart meters, time-of-use tariffs and off-peak deals

Smart meters are now common across the UK, and in 2025 they power a growing range of time-of-use and off-peak tariffs.

These tariffs can be attractive if you can shift a meaningful portion of your usage to cheaper times, for example:

• Running washing machines, dishwashers or EV chargers overnight.
• Heating hot water during off-peak periods.
• Using smart plugs and timers to move usage out of peak hours.

However, if your household mainly uses energy during peak times (early evening), some time-of-use tariffs could cost more. Always compare the estimated annual cost based on your real usage pattern, not just the headline off-peak rate.

How the Ofgem price cap affects comparisons in 2025

The Ofgem price cap sets a maximum price that suppliers can charge per unit of energy and standing charge on standard variable and default tariffs. It is reviewed periodically through the year.

Key points for 2025:

• The cap does not limit your total bill; you still pay for the energy you use.
• It applies mainly to standard variable tariffs, not all fixed deals.
• Cheaper fixed or special tariffs can still be available below the price cap.

When comparing tariffs, don't assume the price-capped default tariff is always best value. Use your kWh usage and compare the total annual cost of each option.

Common mistakes when comparing energy tariffs

Avoid these frequent pitfalls that can lead to disappointing savings:

• Comparing only monthly Direct Debit amounts instead of the unit rates and standing charges behind them.
• Ignoring exit fees on fixed tariffs, which can wipe out savings if you switch again soon.
• Using inaccurate usage estimates that don't reflect your real consumption.
• Overlooking standing charges, especially if your usage is low.
• Not checking eligibility for special tariffs that require smart meters, online billing or regional availability.

By focusing on the total annual cost and reading the tariff summary, you can sidestep most of these issues.

When should you switch gas and electricity in 2025?

You can usually switch energy supplier or tariff at any time, but some moments are especially useful:

• When your fixed-rate deal is ending and you've received your renewal notice.
• If your supplier announces a price increase and you are on a variable tariff.
• After Ofgem price cap updates, when new deals may appear.
• When your household circumstances change — for example, you start working from home or add an electric vehicle, changing your usage pattern.

Ofgem rules also allow you to switch within the last 49 days of a fixed contract without paying exit fees (check your supplier's exact policy).