Best and Worst UK Energy Suppliers (2025)

While many people prioritise cost when it comes to choosing an energy supplier, customer service is another key factor when deciding which is the best energy provider for you. In order to identify the best and worst energy providers, we've gathered data from Citizens Advice's most recent customer survey of 16 suppliers—because when people are unhappy with the service they've received, they often complain to Citizens Advice about their experience.

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Best Energy Company Comparison

NimbleFins has analysed data from hundreds of thousands of energy customers to see which companies are offering the best deals right now, as evidenced by growing market shares and high customer ratings.

By these metrics, the best energy company in the UK right now is Octopus Energy. Octopus has the best customer experience ratings (e.g. 4.8 stars out of 5 at Trustpilot) and their market share has grown approximately 9 percentage points in the past year (from an average of 14% in Q2 2023 to 23% in Q2 2024). In fact, Octopus is about to overtake British Gas (24% market share) as the most popular UK energy company—Octopus already has the best share of the electricity market (23%).

This doesn't surprise us, as Octopus is clearly working hard at being the best—for example, they have the most innovative energy deals for EVs, time of use tariffs and solar energy. This doesn't just include cheap energy deals, but also some of the best payments when selling energy back to the grid.

EDF is second-best in terms of customer rating, while Utility Warehouse is second-best in terms of gaining market share.

The table below ranked energy companies from best to worst in terms of changing market share—we agree with the hundreds of thousands of customers and where they choose to buy energy.

Electricity Market ShareGas Market ShareAverage Energy Market Share1 Year Change (percentage point change)Customer Rating
Octopus Energy23%23%23%9.14.8
Utility Warehouse3%3%3%0.44.4
So Energy1%1%1%0.14.1
British Gas20%27%24%-0.44.2
EDF11%9%10%-0.54.6
OVO13%11%12%-0.64.5
Scottish Power8%7%8%-0.64.3
E.ON17%14%15%-0.84.4
Utilita3%0%1%-1.34.3

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The UK's 9 Best Energy Suppliers

According to data from the three months from April to June 2024, Ecotricity, Utility Warehouse and E (Gas and Electricity) were the top three energy providers in terms of customer satisfaction. Overall, scores have dropped in the current energy-challenged environment, some energy providers have really tried to step up their customer service game.

For example, Ecotricity moved from #10 last quarter to #1 this quarter with an overall score of 3.8 out of 5, and E moved from #11 to #3 over the same period. #2 Utility Warehouse and #3 E both scored 3.4 out of 5 overall.

In terms of contact waiting time, the top three all achieved 4 out of 5 stars, and in terms of customer commitment, they all earned 3 stars. Compared to #1 Ecotricity, #2 Utility Warehouse and #3 E dropped a mark in the number of complaints category, in which they achieved 2 out of 5 stars.

(See what 'customer commitment' means in the methodology section at the bottom of the article.)

For reference, the average customer rating score was 3.1 stars out of 5 (down from 3.3 stars in 2019 but up from 2.9 stars last quarter). So overall scores have dropped in recent years, but they are now improving. Of the top 5 largest energy suppliers in the UK, only Scottish Power was ranked in the top 5 for customer service.

Top 8 Best Energy Suppliers

Rank (1 = best)SupplierFewer complaintsCustomer service contact timesCustomer commitmentsOverall rating
1Ecotricity3433.8
2Utility Warehouse2433.4
3E (Gas and Electricity)2433.4
4Outfox The Market2453.3
5ScottishPower1453.3
6Ovo Energy1453.3
7Good Energy3333.2
8E.ON Energy2353.1

Note, a high ranking doesn't mean that a supplier has the cheapest rates, or that it will even be around. Previously, Affect Energy ranked in the top 5 according to the Citizens Advice data—they subsequently ceased to supply gas to all customers and had their Gas Supply Licence revoked...

Other notable changes: A few quarters ago, Octopus reigned supreme with the top spot but they've since dropped into the bottom half of suppliers. And in our last update, Shell ranked #1 but they've since been bought by Octopus.

The UK's 7 Worst Energy Suppliers

At the other end of the spectrum, the five worst energy suppliers in the study were Utilita (ranked the worst), EDF, Rebel Energy, British Gas and Octopus. None of these scored higher than 2.9 out of 5 stars for overall customer satisfaction. In total, there were 15 energy companies in the study so the 'worst' is ranked number 15. However, there has been some marginal improvement in this lot, e.g. Utilita previously scored just 1.5 out of 5 stars, and they've improved to 1.9 now.

Worst 7 Energy Suppliers

Rank (16 = worst)SupplierFewer complaintsCustomer service contact timesCustomer commitmentsOverall rating
9Co-Operative Energy2353.1
10So Energy1453.1
11Octopus Energy2352.9
12British Gas1452.9
13Rebel Energy2402.7
14EDF Energy2252.4
15Utilita1231.9

Ofgem, the energy regulator, has stepped in on occasion in an effort to improve customer service at the worst offenders. For instance, six years ago, Iresa was banned from taking on new customers until they implemented measures such as responding to customer emails within five working days, recording all customer complaints and identifying vulnerable (e.g., those in debt) customers. Ofgem was not satisfied with the level of improvement in customer service and threatened to revoke Iresa's licence.

Note: There was not enough data on a number of energy suppliers, in particular the smaller companies; without a full data set across all categories these suppliers were excluded from the study. These suppliers might have landed on the best or worst lists, displacing another energy supplier, but we can't know without the data. Citizens Advice only displayed data for suppliers with over 25,000 customer accounts.


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Methodology

We compare energy suppliers' customer service data from Citizens advice that looks at data from a number of reliable sources; suppliers with more than 25,000 customer accounts are included.

Complaints received

The complaints rating is based on data from:

  • Citizens Advice Consumer Service
  • Extra Help Unit
  • Energy Ombudsman
  • Advice Direct Scotland

Customer service wait times

The customer service rating regarding contact wait times is based on supplier-supplied data related to:

  • average call centre wait time (excluding time spent in sales lines)
  • proportion of emails answered within 2 working days
  • average response time for social media messages (applies if the company is contacted more than 5% of the time through social media)

Customer commitment

Suppliers can score 3 points for being part of the Energy Switch Guarantee and another 3 points for the Vulnerability Commitment (with a max score of 5, not 6, if they do both). Trial members of the Energy Switch Guarantee score 2 points, not 3.

The 'Energy Switch Guarantee' means suppliers have to meet certain criteria such as completing 98% of switches within 5 working days, the whole transfer between tariffs or suppliers will be handled by the supplier of the tariff you are moving to, you have 14 days to change your mind, and more. Find out more about the Energy Switch scheme on the Energy UK website.

The 'Vulnerability Commitment' means suppliers have to promise to improve their support to vulnerable customers (i.e. those who might be facing financial difficulties or illnesses). Find out more about the Vulnerability Commitment on the Energy UK website.

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