Best and worst energy firms revealed: what to do if you're unhappy

Updated on 13 April 2023

The best and worst energy suppliers for customer service have been revealed. If yours is among them, here’s how to switch.

Best & worst energy suppliers revealed

Customer service is a crucial element when selecting an energy supplier, but how do you work out which firms will treat you well.

A good place to start is the annual customer service survey carried out by Which?, based on the responses from customers of those firms as well as Which’s own assessment of how those suppliers work.

The customer score was calculated by looking at responses on things like accuracy of payments, communication about the energy market and how well they deliver value for money. 

Meanwhile Which? looked at things like their performance when tackling complaints, customer service levels and the support on offer for vulnerable customers.

Here’s how the top five look based on the Which? study. 


Customer score

Which? score 

Overall score

Octopus Energy








Utility Warehouse




Co-op Energy








The first thing that jumps out here is that these suppliers are not exactly big names, not the sort of suppliers you would necessarily turn to first.

It’s also striking that other than Octopus, the other four in the top five received scores from their actual customers that were not exactly ringing endorsements. It was only their performance in the assessments from Which? that bumped up their overall scores.

On the subject of Octopus, it was the only supplier to be awarded five stars in any category by customers, nabbing the maximum score for usefulness of information about energy costs. It also got four stars in the other categories.

Perhaps unsurprisingly, it was the supplier customers were most likely to recommend to their friends and family, with 87% giving Octopus the thumbs up to their loved ones.

Now let’s take a look at the suppliers who did worst in the study:


Customer score

Which? score 

Overall score

Scottish Power




EON Next








So Energy




Shell Energy





This time around there are far more names that most of us will be familiar with. Indeed, they are some of the biggest suppliers in the country. 

And again, across the board, they performed better in the Which? assessment than from the actual customers.

Both SSE and Shell for example have at least 20% difference in the score between their customers and the Which? team.

Shell was the supplier that customers were least likely to recommend to others, with just 47% saying they would do so. That’s compared with an average of 61% across all suppliers.

Picking up the phone

Which? isn’t the only organisation that digs into the customer service levels on offer from energy providers.

Citizens Advice for example also conducts an analysis of the customer service levels on offer from energy suppliers, and has concluded that standards have reached a new low. 

Suppliers are ranked based on things like how long it takes for them to answer the phone or respond to emails, both of which have slipped of late.

According to Citizens Advice callers faced a typical wait of six and a half minutes (391 seconds) to speak to someone in the first three months of 2022, compared to less than four minutes (224 seconds) during the same period of last year. 

This is just the average of course, meaning some suppliers are far slower at picking up the phone.

Citizens Advice found that one supplier takes a farcical 16 minutes on average to answer calls.

Suppliers were also found to be getting slower at responding to emails, with only 62% responding within two working days. That’s down from 66% during the same period last year.

Here are how the six top-scoring suppliers shape up according to Citizens Advice, based on their customer service standards.


Customer service rating (out of five)



Outfox the Market


Bulb Energy


Affect Energy


Co-operative Energy


Octopus Energy


As you can see, bar EDF, none of these names are exactly household names.

What’s more, the scores are not particularly impressive, highlighting that even the best suppliers for customer service have some work to do.

And here is how things look at the bottom of the table.


Customer service rating (out of five)



Ovo Energy




E.ON Energy


Boost Power




How much should I be paying?

The size of our energy bills has been a huge concern for most of us for the last year. The rocketing prices led to the Government stepping in, imposing an energy price guarantee.

This limits the unit cost of gas and electricity that households will pay, and means that for the year to April 2023 the typical household will pay around £2,500.

That unit cost cap is increasing from April, though the guarantee will remain in place, meaning that the typical household will pay around £3,000 a year.

Energy deals: where to start

The first thing you need to do if you want to switch is to find a supplier to switch to!

That's not really an option at the moment, with very few suppliers even offering deals to new customers currently, though as the market stabilises that should change.

As a rule of thumb, opting for 'dual fuel' (both electricity and gas from the same supplier) is generally cheaper than getting your energy from different suppliers.

Companies usually give hefty discounts on dual fuel tariffs and for paying by monthly direct debit. But it's worth doing your homework all the same.

The smartest way to find the best tariff is to use a price comparison service, which will hunt down the best deals, and tell you how much you can save compared to your current tariff.

To help you do this, you should have details of your current tariff to hand, including an up-to-date meter reading, as that will provide a more accurate comparison.

However, it’s important to bear in mind that given the upheaval in the energy market of late, signing up for a new fixed tariff may end up costing you more than sticking with your supplier’s standard tariff.

Sifting through the jargon

Once you've found the right deal to move to, it's time to switch. You'll be asked for your contact details, and will receive a confirmation email to let you know the switch is in progress.

If you're switching electricity supply, you'll also be asked for your Metering Point Administration Number (also known as the MPAN, your 'Supply number', or, for hardcore utilities fans, the 'S' number).

This can be found on your electricity bill with a large S in front of it, followed by a grid of 13 numbers. You'll only need to quote the numbers to your new provider.

Similarly, if you're switching your gas, you'll need to quote your Meter Point Reference Number, (MPRN or M number), which should also be printed on your gas bill.

If you can't find these numbers, contact your current energy supplier, who will be able to give these to you.

Cooling-off period

Once you've switched, you'll have a cooling-off period of between seven and ten days to change your mind without penalty.

Once this has passed, your supplier will send you a welcome pack outlining your terms and conditions, or a standard letter followed by further information as your switch progresses.

You're likely to receive a lot of correspondence from both your new and old suppliers during the switch, so it's a good idea to keep anything received in a folder you can easily get to, should any queries arise.

In addition, it's important not to be complacent when it comes to switching. In theory, after you've given over your details and a couple of meter readings, your new supplier should take care of all the formalities.

However, relying on the supplier can delay the switch.

It's wise to give your final meter reading to both your new and old supplier. Not only will this speed things up at both ends, but you'll be able to settle any outstanding amounts owed with greater ease.

In addition, cancel any direct debit arrangements – but only after you've paid your final bill, and make sure you let your bank(s) know too.

Will I be left without gas or electricity?

Thankfully no. As all the energy suppliers use the same pipes, meters and equipment to pump gas or electricity into your home, there is never any interruption in service.

Nobody is going to suddenly turn off a tap to your gas or electricity supply, and the only thing you should notice is a cheaper bill each quarter once you've completed the switch.

In some cases, you may be required to get a smart meter which should generally be paid for by the energy company.

Services that do the switch for you

We get it: finding a new energy provider is dull.

A new generation of comparison sites is now offering auto-switching, where they will pick a new energy provider for you in order to save money.

The idea is you'll always get the cheapest deal, whilst they get paid commission by energy suppliers each time they move you (and some also charge minor fees). 

You can read more about these auto-switching services here.

Getting 'green' electricity

It's possible to get electricity generated from renewable sources, without paying much extra.

An increasing number of new and existing providers are offering '100% green' electricity.

Energy providers should be able to tell you the exact percentage of their electricity from renewable sources.


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