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Best and worst energy companies

Which? energy survey results

By Sarah Ingrams

Article 1 of 3

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Which? energy survey results

Find out what thousands of energy customers think of their suppliers. Use our research to choose the best energy company for you.

Our biggest-ever UK energy satisfaction survey covers 31 suppliers in Great Britain and all seven in Northern Ireland, and captures the experiences of nearly 9,000 energy customers. This gives you the most comprehensive view of energy suppliers yet – and a unique guide to choosing the very best energy companies and avoiding the worst.

As well as rating the 'Big Six' energy suppliers - British Gas, EDF Energy, Eon, Npower, SSE and Scottish Power - we also investigate smaller companies. This includes Extra Energy, First Utility, Ovo Energy, Co-operative Energy and Utility Warehouse. Their customers tell us what they really think of the service they receive, so you can use our results to find out which firm is best for you.

This year, medium-sized supplier Utility Warehouse topped our rankings. Big Six firm Npower finished in last place again.

Just one energy company earned our prestigious Which? Recommended Provider Award: small newcomer energy firm Octopus Energy. Read on to see how other energy suppliers – including yours – fared. Or find out what it takes for a company to be awarded a Which? Recommended Provider for energy.

If you live in Northern Ireland, we’ve reviewed every energy firm - including Power NI and SSE Airtricity. Find out which are the best and worst Northern Ireland electricity and gas firms, according to their customers.

Want to know which energy companies have the best tariffs? It's quick and easy to switch energy supplier with Which? Switch, our impartial free switching site. See how much money you can save – compare gas and electricity prices.

Best and worst energy companies

We asked 8,761 energy customers to rate their energy suppliers’ customer service (both online and over the phone), how they deal with complaints, their value for money, the accuracy and clarity of bills and whether they feel the energy company helps understand and reduce their energy use.

See the full results of our survey in the table, below. Click on each company to find out more about it. Expand the table to see the full results, including whether companies passed our pricing assessment using the link at the end.

Energy companies rated
  Company Bills accuracy and clarity Customer service (phone) Customer service (online) Value for money Customer score
England, Scotland and Wales

  Utility-Warehouse small.logo 

Utility Warehouse



Flow Energy



Octopus Energy

- - 76%

   Pfp energy table 

PFP Energy

- - 76%

  Utilita logo-table 




Avro Energy

- - 72%

   bulb logo 2018 table  

Bulb Energy

- 72%

 Ovo energy table   

Ovo Energy


   Ecotricity small.logo 


- - 71%


So Energy

- - 71%


Bristol Energy

- - - 70%



- - 68%

   First-Utility small.logo 

First Utility


   MandS-Energy small.logo 

M&S Energy



Robin Hood Energy

- - - 66%



- 64%


GB Energy Supply

- - 61%

   Green star energy 

Green Star Energy



Co-operative Energy



Good Energy

- - 60%

   isupply table new 

iSupply Energy

- - 56%

   EDF-Energy small.logo 

EDF Energy


  Eon small.logo 



   Sainsburys-energy small.logos 

Sainsbury's Energy






British Gas


   Scottish-Power small.logo

Scottish Power


   Economy energy table 

Economy Energy

- - 50%

 Extra-Energy small.logo   

Extra Energy

- - 49%

   Spark-Energy small.logo 

Spark Energy


  Npower small.logo



Click here for the full survey results table

Table notes
The customer score combines customers’ overall satisfaction with their likelihood to recommend, and is not directly linked to the star ratings.
Overall average customer score: 55%. This is weighted for the market share of each energy company.
(-) indicates too few responses to give a rating.
In bold – customer scores over 70%, above average procedures and practices score and combined 2017 call waiting and complaint score.
Sample sizes: Utility Warehouse (100), Flow Energy (44), Octopus Energy (40), PFP Energy (39), Utilita (58), Avro Energy (40), Bulb Energy (37), Ovo Energy (198), Ecotricity (40), So Energy (31), Bristol Energy (30), Ebico (40), First Utility (250), M&S Energy (60), Robin Hood Energy (30), Iresa (39), GB Energy Supply (34), Green Star Energy (58), Co-operative Energy (148), Good Energy (35), iSupply Energy (40), EDF Energy (871), Eon (1,094), Sainsbury’s Energy (149), SSE (690), British Gas (2,195), Scottish Power (822), Economy Energy (40), Extra Energy (40), Spark Energy (40), Npower (739). Survey: September 2017.

Looking for our Northern Ireland results? Go to Northern Ireland electricity and gas firms.

Interpreting the Which? energy survey results

Energy companies are ordered in our table, above, based on their customer score. The full survey table (click the link below the table to reveal this) also shows how the companies scored on our other criteria, including customer service, value for money and bills.

So if great online customer service is important to you, our table reveals each company's customer service rating for online (and a separate rating for phone customer service). The more stars, the better.

Who's top of the Which? energy survey?

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Utility Warehouse tops the table this year, closely followed by Flow Energy, newcomer Octopus Energy, and PFP Energy

It’s not our top-scoring supplier that’s this year’s only Which? Recommended Provider (WRP) for energy though; that accolade goes to Octopus Energy.

Utility Warehouse and PFP Energy missed out on WRP status because they both scored below average on our procedures and practices assessment (expand the table to see this). Flow Energy isn’t a WRP because it scored below average in our performance assessment, which takes into account waiting times and complaints.

Price is the most important consideration for you when choosing a new energy supplier, according to our survey, so it’s no surprise that the highest-scoring energy companies are considered good value for money by their customers.

Price isn’t everything though – and being rated good value for money by customers doesn’t mean an energy supplier is the cheapest on the market. Renewable energy firm Ecotricity (in joint 9th place) has one of the priciest tariffs on the market. But its customers rate it good value for money, showing that it keeps them satisfied.

In fact, our survey shows the importance of customer service. The most common reason that customers switch to lowest-rated company Npower is for lower prices. But the main reasons customers say they leave the supplier are bills being too high, fixed deals ending, or poor customer service.

The Big Six

The biggest six energy suppliers are in the lower half of the table. Npower is the lowest-scoring supplier again this year, while EDF Energy and Eon jointly score 10 percentage points higher. 

See our Big Six energy companies guide for full details about each firm.

Who's bottom of the Which? energy survey?

Npower, Spark Energy and Extra Energy bring up the rear in our table. Npower’s customers always score it worst, but this year other firms’ scores are closer to it. 

Spark Energy was in 12th position last year but sits in 30th place in 2018. It has the joint-largest percentage of very dissatisfied customers, alongside Npower (5%). 

Spark Energy has grown quickly and, from our years of studying energy firms, we’ve seen rapid expansion cause other firms’ falls from grace.

How quickly do energy companies respond to customers?

Although you can contact most energy companies by email, live chat and social media, the majority of us still choose to pick up the phone to speak with our energy company.

We conduct snapshot undercover investigations to reveal how long customers have to wait for their phone calls to be answered by a human being. We also contacted energy suppliers via live chat (if they offered it) or email or online form (if they didn’t offer live chat) to find out how long it takes to get a response that isn’t an automated acknowledgement.

In our latest investigation in September and October 2018, we contacted energy suppliers a total of 822 times. We made 460 phone calls to 38 energy companies, sent 422 emails, online form requests and live chat messages.

Which energy companies are quickest?

Answering the phone quickly is not impossible. Affect Energy managed to answer calls to its customers services in just 10 seconds on average, making it the fastest energy supplier to put us through to a human. 

Overall there were six firms that put us through to a human in under a minute this year.

To see the full results of our 2018 investigation, read our story on energy company customer waiting times 2018, which includes how promptly companies responded to live chat and whether it’s worth emailing if you need a speedy response.

We can help you save money on your energy bills. Use our independent free switching site, Which? Switch, to find the cheapest energy deal.