Best and worst energy companies revealed

Npower has once again been rated as the worst gas and electricity supplier in the annual Which? Switch energy customer satisfaction survey.

What's in your energy bill?

But Npower isn't the only big name that failed to impress. The big players were all trounced by smaller suppliers Ovo Energy and Utility Warehouse, which topped the leader board with a customer score of 77%.

For full survey results of the ten suppliers featured - including ratings for bills, value for money and customer service - have a look at the energy customer satisfaction survey

As well as a ranking by customer satisfaction score, you'll also find a guide to switching supplier if you think your gas and electricity providers aren't up to scratch.

Top for service

Utility Warehouse and Ovo Energy were unbeaten for their customer service - with top marks for online support and dealing with queries. First Utility, which got a rock-bottom rating for dealing with queries, joins Npower for the joint-lowest rating for customer service.

The big six includes household names British Gas, EDF, Eon, Npower, Scottish and Southern Energy and Scottish Power. But our survey shows smaller suppliers Ovo Energy and Ebico got better ratings for encouraging energy efficiency than all the big six - with the exception of Eon.

Energy suppliers that have more than 50,000 customers - which means all the big six suppliers - are obliged under to the Carbon Emissions Reduction Target (Cert) to promote energy saving measures - such as cut-price loft insulation - to their customers.

Live energy Q&A - Which? Member exclusive

If you're having problems with your energy supplier, join us on 27 January from 12.30pm on Our team of energy experts, including from the team here at Which? Switch, will be answering all your energy questions live - from how to find the best tariff to tackling problems with your gas and electricity supplier and switching supplier.

Log in to visit our energy Q&A page at to find out more and sign up for an email reminder.

What's in your bill?

It doesn't matter which energy supplier you're paying if you don't know what you're paying for. According to energy industry watchdog Ofgem, only 43% - or £495 - of the average dual fuel bill goes towards the wholesale cost of your gas and electricity.

An extra £655 per customer per year is slapped onto your bill, including £230 in network costs (including distribution), £127 in operating costs (including billing and customer service staff), £92 for the government's environmental and social schemes (such as Cert), £58 in VAT and an extra £58 to cover any other costs, such as metering. This leaves a net margin of £92.

Our research shows that your gas and electricity bills could be clearer about where your money's going. There's room for improvement from First Utility and the big six suppliers when it comes to the clarity of the bills they send. Npower - consistently the worst supplier in our surveys - got the lowest rating of all for both the accuracy and clarity of its bills.

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This figure is the average estimated annual saving for customers who applied to switch suppliers through Which? Switch between 1 January 2014 and 31 March 2014.

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