If you're switching supplier

Note down the following from your recent energy bills before switching energy suppliers:

1. Name of your supplier.

2. Name of tariff / plan.

3. Amount of gas and electricity you've used in kilowatt hours (kWh) - calculate an annual or six month figure using recent bills.

You can also find your MPAN number for electricity, and MPRN number for gas, on your bill. These unique reference numbers identify the meter at your property. If your exact meter can't be located when switching energy suppliers, we'll ask you for this number instead.

What you'll need to switch

Need help locating the information you need to switch? Here are some sample bills with important information highlighted:

• British Gas bill
• British Gas annual statement
• EDF Energy bill
• EDF Energy annual statement
• E.ON bill (before December 2013)
• E.ON annual statement (before December 2013)
• E.ON bill (from December 2013 onwards)
• E.ON annual statement (from December 2013 onwards)
• First Utility bill
• First Utility annual statement
• Npower bill and statement
• OVO Energy bill
• OVO Energy annual statement
• SSE statement
• SSE gas and electricity bill
• Scottish Power bill
• Scottish Power statement

Gas and electricity meter readings

You can check whether your energy bill is based on a gas or electricity meter reading taken by either you (usually indicated by the letter 'C' for customer) or your energy supplier ('A' for actual) - or whether it's an estimated reading calculated by your energy supplier ('E').

Check your energy bills are based on meter readings

If your energy bill is based on an estimated meter reading you should read your gas or electricity meter yourself and provide this information to your energy supplier, so it can send you a revised gas or electricity bill, based on your actual usage.

We suggest you read your own gas and electricity meters every three months.

Paying energy bills by direct debit

If you pay by monthly direct debit, you'll still receive a regular bill. Your supplier works out how much you spend on energy in a year and divides this up into equal monthly payments. Energy suppliers often offer a discount if you pay in this way, because it guarantees payment to them, but there are lots of other ways you can pay your energy bill.

You should keep a regular check on your bills to make sure your supplier is asking you to pay the right amount. Bear in mind that because energy use is not equal throughout the year, direct debit customers effectively underpay in winter and overpay in summer - but it's sensible to question any particularly large credit or debit balances with your supplier.

If you don't think you're paying the correct amount, contact your energy supplier to ask for a breakdown of how your direct debit amount is calculated.

Cutting your energy bills

Switching to a different supplier and tariff - or simply choosing to pay your existing one by direct debit, or managing your bills online - could cut your gas and electricity bills.

With Which? Switch, you can compare the latest deals from all the major suppliers - have your recent energy bills to hand while you're running a comparison to get results specifically tailored to you.

More on energy...

• Read our guide to the different types of energy tariff
• Find out how to read your electricity meter
• Check out our guide to switching energy supplier