Best and worst energy companies

Energy companies

Best and worst energy companies

By Sarah Ingrams

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Best and worst energy companies

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

As well as rating the 'big six' energy suppliers - British Gas, EDF Energy, Eon, Npower, SSE and Scottish Power - every year we also investigate smaller companies including Extra Energy, First Utility, Ovo Energy and The Co-operative Energy, finding out from customers what they really think of the service they receive.

This year, smaller supplier Ovo Energy came out on top. While big firm Npower sits at the bottom. Keep reading to discover the best and worst UK energy suppliers.

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 - find the cheapest energy deal.

Best and worst energy companies

We asked more than 8,902 energy customers to rate their energy suppliers on their customer service, the way they deal with complaints, value for money, accuracy and clarity of bills and whether they feel the energy company helps them to save money. You can see the full results of our survey in the table, below. Click the links if you want to find out more about individual energy companies.

Flow Energy is our Which? Recommended Provider in 2016. This is because Flow passed all of our thorough assessments on policy, practices and pricing (scroll down past our table, to find out more). Ovo Energy was also a Which? Recommended Provider until August 2016, when it raised its prices.


Energy companies rated
  Company Customer service Value for money Bills (accuracy and clarity) Complaints Helping you to save energy Customer Score
England, Scotland and Wales

Ovo-Energy small.logo

Ovo Energy


Good-Energy small.logo

Good Energy


Ecotricity small.logo





- 76%

Utility-Warehouse small.logo

Utility Warehouse





Flow small.logo

Flow Energy

- - 73%

MandS-Energy small.logo

Marks and Spencer Energy

- 69%


GB Energy Supply

(no longer trading)

- - - 66%

First-Utility small.logo

First Utility


 Green star energy

Green Star Energy

- - - - - 61%


iSupply Energy

- - - 58%

Spark-Energy small.logo

Spark Energy

- 58%

EDF-Energy small.logo

EDF Energy


British-Gas small.logo

British Gas


Eon small.logo



Sainsburys-energy small.logos

Sainsbury's Energy


SSE small.logo



Extra-Energy small.logo

Extra Energy


Co-op-Energy small.logo

The Co-operative Energy


Scottish-Power small.logo

Scottish Power


Npower small.logo


Northern Ireland

Budget-Energy small.logo

Budget Energy

- - - - 65%

Power-NI small.logo

Power NI


SSE-Airtricity small.logo

SSE Airtricity


Click here for the full survey table

Table notes
Which? Recommended Providers in red.
The Customer Score combines customers’ overall satisfaction with their likelihood to recommend, and is not directly linked to the star ratings
Overall averages - 54% for both GB and NI, weighted for market share of each energy company
‘Helping you save energy’ - a rating of how the supplier helps you to save energy
‘Complaints’ - a rating of how well respondents felt the company was dealing with their complaints.
(-) - too few responses to give a rating
In bold - scores over 70% for customer satisfaction score and over average for policy score and customer experience assessment score
Sample sizes: Ovo Energy (244), Good Energy (43), Ecotricity (56), Ebico (59), Utility Warehouse (129), Utilita (54), Flow Energy (43), Marks and Spencer Energy (63), GB Energy Supply (36), First Utility (277), Green Star Energy (31), iSupplyEnergy (32), Spark Energy (34), EDF Energy (875), British Gas (2,296), Eon (1,128), Sainsbury's Energy (153), SSE (1,062),  Extra Energy (106), The Cooperative Energy (158), Scottish Power (846), Npower (783), Budget Energy (31), SSE Airtricity (83), Power NI (135). Survey: October 2015.

Interpreting the energy survey results

Energy companies are ordered in the above table based on their customer score. The full survey table also shows how the companies scored on our other criteria. So, for example, if great customer service is important to you, our table reveals each company's customer service rating - the more stars, the better.

In our customer satisfaction survey, we asked customers to rate their energy company based on customer service, value for money, clarity and accuracy of bills and how it deals with complaints. We then asked how satisfied they were overall, and whether they would recommend their energy company to a friend – this then forms the customer satisfaction score. 

We also investigated out how long it took, on average, for a human being to answer the customer service and sales lines of each company.

Which? review of energy companies

In addition to the satisfaction survey results, Which? carried out a comprehensive analysis of energy companies' practices, policies and prices. We awarded Which? Recommended Provider status to the best performing companies.

To be rated as Which? Recommended Provider, an energy supplier needs to:

1. Be in the top group of companies rated the highest by their customers.
2. Have no fines or sanctions brought against them by regulatory bodies, such as Ofgem and the Advertising Standards Authority, in the past year.
3. Follow policies that we think are in the best interest of the consumer. We scored energy companies against a set of 32 criteria that cover the main elements of the consumer journey including: complaints processes, billing, customer service and account management.
4. Be better than average on call waiting times to their customer service and sales lines.
5. Pass our final price analysis. They need to have a variable or fixed tariff in the cheapest part of the market for low, medium and high users for the average user across Great Britain. They also cannot have a variable or fixed tariff in the most expensive band.

The supplier that passed on all of our criteria and is therefore an energy company to be rated as Which? Recommended Providers is Flow Energy

Ecotricity and Ebico are close contenders and pass on all criteria except price - so are worth considering if you don't mind paying a bit more for a good service. Ovo Energy was also a Which? Recommended Provider until August 2016, after it raised its prices.

Energy company customer service

After price, customer service is the most important factor for consumers when choosing an energy supplier. Our survey shows how customers rate their energy provider on customer service. 

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We also carry out our own research, checking how long it takes to get through to the energy companies on the phone.

In total, energy companies' customer service departments are contacted an astounding 70 million times a year, and 90% of these are phone calls. So we conduct snapshot investigations into how long customers have to wait to have their phone calls answered by a human being when they ring customer services.

In our latest investigation in September and October 2016 we made 552 calls to 23 energy suppliers. We called each supplier's customer service and sales numbers where available. 

Answering the phone quickly is not impossible. Ebico has managed to answer calls to customer services in less than 30 seconds on average in all of our five mystery shopping investigations so far. To see the full results of our investigation, read our story on energy company call waiting times

When using our price comparison site, Which? Switch, to find the cheapest energy deal, it's important to consider customer service. A cheap deal could end up costing you more if you're constantly on the phone to your supplier. 

So take a look at our full reviews of each energy company to see how they fared in our surveys and investigations - scroll back up to the table and click on the companies' links. 

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