Frequently Asked Questions

You will need the following details to switch gas and electricity suppliers using Which? Switch:

• Postcode (as energy prices vary between regions). If you don't know this yet (if you've just moved house for example), we'll ask for the area you live in instead.
• Current energy supplier's name.
• The name of your current energy tariff.
• How much gas and electricity you use each year (or how much you spend).
• Your preferred energy bill payment method (you'll need your bank or credit card details to hand if you want to pay by direct debit).

If for some reason your exact meter reading can't be located during switching, you may also need to provide your gas and/or electricity meter numbers (known as MPRN and MPAN numbers).

To get the most accurate idea of how much money you'll save by switching, it's best to have recent gas and electricity bills to hand. If you are unable to provide exact readings, Which? Switch can give you estimates of your gas and electricity usage/bills by using information on your personal circumstances, such as how many people live in your house and the number of bedrooms.

To take a look at some sample bills showing the information you'll need to switch, visit our guide to understanding your energy bill.

Check your recent gas and electricity bills for details of your current energy supplier(s).

You can also find out which company supplies your gas by contacting the Meter Number Helpline on 0870 608 1524. To confirm your electricity supplier, contact your regional electricity supplier - you can find its phone number using directory enquiries.

Your MPAN is the unique identifying number for the electricity meter at your property, often referred to as a 'Supply Number' or 'S' number. When you apply to switch electricity supplier with Which? Switch we can usually find your MPAN automatically from the national meter database. However, sometimes we may need to ask you for it, usually when the database information is incomplete.

Your MPAN should appear on your electricity bill- you can check where to find this on bills for all of the larger suppliers with our understanding your energy bill guide. If you can't locate your 'S' number, you should contact your current electricity supplier, who'll be able to tell you the number.

Your supply number will normally be shown on your bill using a large 'S' and a grid of numbers. All we need is the bottom row of numbers (13 digits) to ensure your switch happens as smoothly as possible.

If more than one MPAN is displayed, please select the relevant MPAN you want to switch.

If you've found your MPAN and are ready to switch, start comparing energy prices now with our free and impartial service.

Your gas MPRN, often referred to as an 'M' number, is the unique identifying number for your property (not your gas meter). It should be printed on your gas bill - usually on the first page or the reverse of the first page. You can check where it's printed on all the major suppliers' bills with our handy guide to understanding your energy bill. The gas MPRN will consist of six to ten numbers and no letters.

If you can't locate your MPRN, or you have just moved into your home and do not yet have a gas bill, you can call the Meter Number Helpline on 0870 608 1524.

If more than one MPRN is displayed, please select the one that is relevant for your property. If you are unsure which MPRN is yours, please check a recent gas bill or call the number above.

Taking regular gas meter readings to pass on to your energy supplier will ensure you receive accurate energy bills.

If you've found your MPRN and are ready to switch, start comparing energy prices now with our free and impartial service.

Unfortunately it isn't possible to estimate when the next gas or electricity price changes will take place. However, you can visit our energy prices Q&A for regular updates about the latest price drops or increases.

The price you pay for energy will be protected from price increases if you choose a capped or fixed rate energy tariff, but you will not benefit from energy price decreases.

Compare gas and electricity suppliers regularly to check prices, as switching is simple and could save you money on your bills. However, always take any exit fees that apply to your current deal into consideration as this may reduce the total amount you would save from switching. You can compare energy suppliers quickly and easily using our energy switching calculator.

If you are on a fixed deal (which guarantees a set price for a certain period), it's sensible to get a quote around two to three weeks before your contract ends, otherwise you could end up being placed on an energy company's standard (and often more expensive) tariff.

The energy market is changing constantly, so getting a quote every 12 months or when your contract is about to end will ensure you stay on top of the market and don't miss out on a competitive deal.

The average saving when switching gas and electricity is £191.

This figure is based on the average annual saving based on customers who applied to switch suppliers through us 1st January 2014 to 30th June 2014 .

If you are on a fixed deal (which guarantees a set price for a certain period), it's sensible to get a quote around two to three weeks before your contract ends, otherwise you could end up being placed on an energy company's standard (and often more expensive) tariff.

Saving energy choices

Here are some of the ways the choices you make about your energy can save you money:

• Understand the different types of energy tariffs available - the cheapest deals are often online discount or variable rate tariffs.
• Energy companies will often offer extra discounts if you take both gas and electricity from them as part of a dual fuel deal.
• Your energy company should give you a choice of ways to pay your energy bills - but the cheapest option is often direct debit.

Use the Which? Switch switching calculator to find the very latest discounts and deals.

We give you the option to enter your energy usage or spend by month, quarter or year, but we recommend you use your annual usage figures where possible.

This is because quarterly or monthly energy bills only provide a snapshot of your gas or electricity usage, which fluctuates with the seasons. Most people use more energy in the winter months than they do in the summer, so using an annual bill will take all seasons into account and give a more accurate picture of your usage.

Annual figures provide a much more accurate prediction of any potential savings.

For the most accurate results, we recommend you enter your gas and electricity inputs as usage in kWh, rather than spend, as kWhs do not fluctuate with price changes.

If you need help locating your consumption figures, take a look at the annotated sample bills in our guide to understanding your energy bill.