Energy switching questions answered
Plain-English answers to common questions about gas and electricity in the UK: how bills work, what tariffs mean, how switching happens, and how this site works. Utility Matchmaker is an information and referral service. We publish educational content about energy. Live comparison and switching take place on our partner platform.
About your energy bill
What makes up a UK energy bill?
Every domestic gas and electricity bill in the UK has two components: a unit rate, charged per kilowatt-hour (kWh) of energy you consume, and a standing charge, a fixed daily amount applied regardless of how much you use. Your total bill is the sum of units consumed multiplied by the unit rate, plus the number of days in the billing period multiplied by the standing charge, with VAT at 5% applied to both.
What is the Ofgem price cap?
The Ofgem price cap sets the maximum unit rates and standing charges that energy suppliers can apply to domestic customers on standard variable tariffs. It is reviewed and updated quarterly. The cap does not limit your total bill; it limits the rates per unit and per day. A household that uses more energy than Ofgem's reference level will pay more than the headline cap figure. From 1 July 2026, the price cap rises to £1,862 per year for a typical dual fuel household paying by direct debit.
Why does my bill change even when I'm on a fixed tariff?
A fixed tariff locks in your unit rates and standing charges, not your total bill amount. If your energy consumption changes (more people in the property, an unusually cold period, a change in how you heat the home), your bill changes even though your rates are the same. The fix protects against rate increases, not against consumption changes.
What is VAT on energy and how is it calculated?
Domestic energy in the UK attracts VAT at 5%, lower than the standard 20% rate. The 5% applies to both unit charges and standing charges. Most tariff comparisons and bills show costs inclusive of 5% VAT. Business energy is charged at the standard 20% VAT rate.
What does dual fuel mean?
Dual fuel means buying both gas and electricity from the same supplier on a single account. It is the most common arrangement for UK households with a gas connection. Single fuel means separate suppliers for gas and electricity. Some properties, particularly newer builds or those without a gas connection, are electricity only.
Why is my energy bill estimated rather than based on actual readings?
If you do not have a smart meter and have not submitted a meter reading, your supplier produces an estimated bill based on historical usage patterns. Estimates can be higher or lower than actual consumption. Submitting regular meter readings, or having a smart meter installed, ensures bills reflect what you have actually used. If an estimated bill turns out to have been too high, any overpayment appears as credit on your account.
About tariffs
What is a standard variable tariff?
A standard variable tariff (SVT) is a supplier's default rate. Customers are placed on it when a fixed deal ends, when they move into a property without choosing a tariff, or when they have not actively selected a deal. SVTs can rise and fall when the supplier adjusts rates, subject to the Ofgem price cap. They usually have no exit fees, meaning you can switch away at any time.
What does it mean when a tariff is described as tracker or flexible?
Tracker and flexible tariffs move in line with wholesale energy price changes rather than being fixed by the supplier independently. Unlike a standard variable tariff, which the supplier can adjust at its discretion, a tracker tariff follows a published index or formula. How quickly and by how much rates change depends on the supplier's specific methodology, which is set out in the tariff terms.
What is a dual fuel tariff versus separate gas and electricity tariffs?
A dual fuel tariff is a single contract with one supplier covering both gas and electricity. Separate contracts mean different suppliers for each fuel, billed independently. Both arrangements are common. The total cost comparison, combining gas and electricity, is what matters when comparing options, not whether they are on one contract or two.
What is a prepayment meter and how does it affect tariffs?
A prepayment meter (sometimes called pay-as-you-go) requires you to top up credit before using energy rather than being billed in arrears. Some tariffs are not available on prepayment meters. Since April 2024, Ofgem's price cap rules have been adjusted so prepayment customers on standard variable tariffs are no longer charged a premium over direct debit customers. Fixed deals and specialist tariffs may still vary.
What does 100% renewable electricity mean on a tariff?
When a supplier describes a tariff as 100% renewable electricity, it means they have purchased Renewable Energy Guarantees of Origin (REGOs), certificates representing electricity generated from renewable sources, equal to the amount their customers use. The physical electricity in the grid is a mix from many sources; REGOs are the accounting mechanism used to match consumption to renewable generation. Suppliers publish an annual fuel mix disclosure showing the sources behind their tariffs.
About switching
Will my gas or electricity be cut off when I switch supplier?
No. Under Ofgem's rules, your supply continues without interruption throughout a switch. The physical pipes and wires serving your property are managed by your regional distribution network, not your supplier. Only your supplier and billing change. Your network connection stays the same.
Can I switch if I owe money to my current supplier?
If you owe more than £500 to your current supplier for gas or for electricity, they may be able to block the switch under Ofgem rules. Below that threshold you are generally free to switch. If you are in debt to your supplier and want to switch, contact them to understand your balance and options before starting a comparison.
How do I find out who my current energy supplier is?
Your supplier's name appears on any bill, direct debit statement, or correspondence from them. If you do not have a bill, for example if you have just moved into a property, you can find the electricity supplier by contacting the local distribution network operator or using the Energy Networks Association postcode finder. For gas, you can call the Meter Point Administration Service on 0870 608 1524.
What meter readings do I need for switching?
You do not need meter readings to start a comparison or apply to switch. However, taking a meter reading close to your switch date is useful. Submit it to your old supplier as a final reading and to your new supplier as an opening reading. This ensures your closing bill from the old supplier and your first bill from the new one are based on actual consumption rather than estimates.
What is the Ofgem Faster Switching programme?
Faster Switching is Ofgem's rules-based programme that reduced the standard domestic switching timeline. Most domestic gas and electricity switches now complete within approximately five working days of the application being accepted, compared to the previous 21-day standard. It has been in effect since 2021.
Can I switch energy supplier if I rent?
If the energy bills are in your name, meaning you pay the supplier directly, you can generally switch. If your landlord pays the bills and recharges costs through your rent, switching is not available to you directly. If you are unsure, check your tenancy agreement or ask your landlord who the energy account is registered to.
What happens if I switch and then change my mind?
Domestic energy contracts include a statutory 14-day cooling-off period from the date you agree to the contract. If you cancel before the switch completes, it is simply stopped. If the switch has already completed within the 14-day window, you can still cancel, but you will need to switch again to move back to another supplier, as the supply has already transferred. You remain liable for energy used between the switch date and cancellation.
How often can I switch energy supplier?
There is no regulatory limit on how often you switch. Practically, if you are on a fixed deal, check whether exit fees apply before switching early. At the end of a fixed term you can switch freely. Many households find it useful to compare again whenever a fixed deal is approaching its end date to avoid rolling onto a standard variable rate by default.
About smart meters
What is the difference between a SMETS1 and SMETS2 smart meter?
SMETS1 meters are first-generation smart meters rolled out from around 2011. A significant number lost their smart functionality when customers switched supplier. SMETS2 meters, rolled out from 2018, communicate through a central network (the DCC) and are designed to maintain smart functionality regardless of which authorised supplier you are with. Many SMETS1 meters have since been enrolled into the DCC network remotely. Your supplier can confirm which generation your meter is.
Do I have to accept a smart meter?
No. Smart meter installation is offered free of charge as part of the national rollout, but it is not compulsory. You can decline installation without affecting your ability to switch supplier or access tariffs. Some time-of-use tariff products require a smart meter, but standard fixed and variable tariffs are available with any meter type.
About Utility Matchmaker
Is Utility Matchmaker free to use?
Yes. Our guides and educational content are free to read. Using our partner comparison tool to check tariffs is also free. We may earn a commission if you switch through our partner link. This commission is paid by the supplier, not by you, and does not affect the tariffs shown in comparison results.
Does Utility Matchmaker provide energy, financial or regulated advice?
No. Utility Matchmaker publishes educational content, switching information, explainers, and resources about UK energy. We are an information and referral service. We do not provide regulated financial advice, personalised energy advice, or regulated switching services. Live comparison and switching take place on our partner platform, TheEnergyShop, which is independently operated.
Where does the actual comparison and switching happen?
When you click any comparison link on this site, you are taken to our partner platform operated by TheEnergyShop. Tariff comparison, postcode lookup, and switching applications are all completed there. Utility Matchmaker does not process applications, hold tariff data, or manage switching; that is handled entirely by TheEnergyShop's platform.
How does Utility Matchmaker make money?
We may earn a commission when a visitor switches energy supplier through our partner comparison link. This is a standard referral arrangement; the supplier pays a fee for each completed switch. It does not change the tariffs available to you or add any cost to your bill.
Are the tariff examples on this site live prices?
No. Any tariff examples shown on this site are illustrative only and are not live quotes. Energy tariffs change frequently and vary by postcode, usage, meter type, and payment method. For live tariffs available at your address, use the partner comparison tool by entering your postcode.