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Are energy comparison sites any good?

By Emma Lunn | Tuesday, May 25th 2021

With the current situation in 2022 in the UK preventing meaningful energy switching, at the current time energy comparison sites aren't going to be much use to you. We will be updating this guide again as soon as the situation returns to normal.

To find the best energy deal on a price comparison website, you need to enter the details of your home and how much energy you use (this information will be on your bill). The price comparison site will then show you the cheapest tariffs available. Once you’ve found a tariff you want, the price comparison site will manage the switch for you.

Unlike most competitive industries, the products from rival energy suppliers are literally identical. Whichever supplier you have, you get the same gas and electricity through the same pipes and cables. This means price is the only real differentiator when choosing a supplier, although energy suppliers do have varying levels of customer service.

How do energy price comparison sites work?

Price comparison sites may be simple for consumers to use, but there’s a lot going on behind the scenes. Each price comparison website works from a database that contains details of all suppliers and their tariffs, and this is updated with new tariffs as and when they become available. The database is maintained and transmitted electronically so the energy price comparison site can upload details of new tariffs as soon as they’re on the market.

Updates are quite complex – the data will include every piece of information about each tariff, in each region, and for each payment and meter type. The data also includes factors like discounts, terms and conditions, and special features.

From the end user’s point of view, searching for the cheapest energy tariff is fairly simple. You input your details and an algorithm puts together a list of all the tariffs available to you in price order. You’ll be able to see the supplier, tariff name and annual cost. The algorithm will also calculate the price difference between what you pay now with your existing supplier and each available tariff. There’s usually the option to filter results and see just fixed or variable tariffs, or those with green credentials.

energy comparison sites midpage

In theory you could work all this out for yourself but it would take a long time, as different suppliers charge for energy in different ways. Some providers apply standing charges while others don’t, and most charge different unit rates per kWh depending on where you live.

Be aware that although the information the various energy comparison sites work from is the same, they may use different methods for interpreting and displaying information and some sites may update their tariff information more regularly than others.

How do energy price comparison sites make money?

Comparison websites are free to use for consumers – they make most of their money from commission from energy suppliers. They earn this money when a customer initiates a switch on the comparison site or ‘clicks through’ to the supplier. The more visits a comparison site can convert into switchers, the more income it will earn.

How much commission is paid by suppliers to the comparison site is secret commercial information, but it’s thought to be about £30 per fuel per customer.

However, not all energy suppliers pay commission and it tends to be small or new companies that don’t – and these are often the cheapest deals on the market. This doesn’t mean these suppliers won’t be listed on price comparison sites, but it won’t be possible to initiate a switch through the comparison site, so you’ll need to contact the supplier directly.

Other ways price comparison sites earn money include advertising and ‘sponsored listings’ which are given more prominence (although not listed as ‘best buys’ unless they actually are).

What information do I need before I compare energy tariffs?

The more information you give the price comparison site, the more accurate the search results will be.

You’ll need to give it your address, the type of fuel you use (gas or electricity), your existing supplier and tariff, how you pay your bills (i.e. monthly direct debit or on receipt of the bill), and how you heat your home (if you have an Economy 7 meter you’ll be shown this type of tariff).

However, perhaps the most important bit of information is how much energy you use each year. This information will be on your annual statement from your energy supplier and is measured in kilowatt-hours (kWh). The price comparison site will use this usage figure to work out how much your future costs are likely to be.

If you don’t know your kWh usage, you can state how much you spend on gas and electricity per month or year, along with your current tariff, and the site will estimate how much energy you use. However, this isn’t always an accurate way to calculate your usage – inputting the number of kWh you actually use will generate a more accurate result.

If you have no idea about your energy bills or your usage at all and are just looking for the best deal out there, most websites now offer a means of working out approximately what you will need, by running you through a series of questions about the size of your home and how many people live there.

Things to watch out for

Ofgem’s Confidence Code

The regulator Ofgem has ‘approved’ a number of price comparison sites. If you use an Ofgem-accredited comparison site, you can trust that the options and prices you find on them are calculated and displayed in a fair, unbiased and accurate way. These websites operate in accordance with Ofgem’s code of practice, the 'Confidence Code'.

Price comparison sites accredited under the Confidence Code must also operate an effective complaints process.

Supplier list

As we mentioned earlier, not all suppliers pay comparison sites commission or accept switches via a third party. Comparison sites give you the option to filter out suppliers that only accept direct customers. Tick box options normally say something like ‘only show suppliers this comparison site can help me switch to’ or ‘Include plans that require switching directly through the supplier’.

To get a full list of the cheapest deals, tick the box that will show you all the tariffs on the market.


Some price comparison sites negotiate super-cheap exclusive deals with suppliers which will only be offered through that particular comparison site. This means that to find the cheapest deal you may have to use several price comparison sites and compare the exclusive deals each offers.


Most suppliers offer a discount if you pay your energy bills by monthly direct debit and/or paperless billing. This should be stated alongside the tariff details in the search results. If you prefer to pay on receipt of a paper bill, a different tariff might be the best one for you.

Frequently asked questions

How can I make a complaint about an energy comparison site?

Price comparison sites accredited under Ofgem’s Confidence Code must operate an effective complaints process. If you have a complaint, you should first contact the comparison site so they can try to resolve it. If you’re not happy with the outcome, contact Ofgem so it can investigate the issue.

How long does it take to switch energy suppliers?

It normally takes about three weeks for a switch to complete. Contained within this timeframe is a 14-day cooling off period in which you can change your mind and cancel the switch free of charge.

What if I have a pre-payment meter for my gas or electricity supply?

You’ll need to specify this when searching for gas or electricity tariffs. It is possible to switch prepayment tariffs to save money, but an even better idea would be to investigate switching to a credit meter if you can. This will give you access to more competitive energy deals.

How often can I change my energy supplier?

You can change energy suppliers as often as you like. However, if you are on a fixed tariff there may be exit fees for breaking the contract early. It’s usually best to shop around and switch suppliers when a fixed term comes to an end.

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