Electricity and gas are essential services and we spend a fair chunk of our income on them – now more than ever. So you shouldn’t have to put up with poor service.
Our annual energy satisfaction survey covers 16 suppliers in Great Britain. Our most recent results were published in January 2025 based on nearly 12,000 energy customers telling us about the service they receive.
We also conducted our own in-depth assessment of firms’ practices to find out which are set up in the best interests of their customers.
The results of both are combined to make our findings as useful as possible to find the companies that are doing their best for customers.
This time three providers impressed us enough to be named Which? Recommended Providers: Octopus Energy, Utility Warehouse and 100Green.
Our table below covers providers available in England, Scotland and Wales. If you live in Northern Ireland, see our advice on NI electricity and gas firms.
Compare prices and contracts with our free energy tool or find out how to get the best energy deal.
Best energy companies
Below are the results from our customer survey and our unique assessment of company practices. We’ve combined these to give a total score for each supplier.
We surveyed 11,984 members of the general public in September-October 2024. We assessed firms’ behind-the-scenes practices in September-November 2024 to compare their approaches to methods of contact, supporting customers who need it, how they performed against their smart meter targets, switching, and complaints data.
We included 17 firms in total. One company (Rebel Energy) didn’t get enough responses to get complete scores from our customer survey and was not included in our behind-the-scenes assessment. All Boost Power customers have now been moved to Ovo. However, the results are still useful to see how your provider compares behind the scenes.
Click the name of each company to read more.
Boost Power is included in the table but our survey was put out before its move into Ovo was complete.
Table notes: Customer results based on a September-October 2024 online survey of 11,984 energy customers among the general public. Customer score: based on satisfaction and likelihood to recommend. Customers rated other service aspects, shown as star ratings. We require 50+ responses to give a rating. Which? assessment score based on a request for information and desk research in September-November 2024. Total score is a combination of customer score and Which? assessment score.
Sample sizes for customer score: Utility Warehouse (427), Octopus Energy (2,469), Ecotricity (115), E (446), Utilita (533), Outfox Energy – formerly Outfox the Market (86), Co-op Energy (177), Sainsbury’s Energy (159), EDF Energy (1,059), Eon Next (1,328), Ovo Energy (1,041), Scottish Power (817), So Energy (164), Boost (65), British Gas (2,618), Rebel Energy (52), 100Green (191), Good Energy (116).
a Rebel Energy received too few responses in our survey to be given a customer score or rate them overall. It did not complete our supplier questionnaire.
b Ovo announced it would be moving all Boost customers to Ovo in 2023. This process is now completed, and it is no longer possible to switch to it. We did not conduct our assessment of practices for Boost as a result, but the Boost customers at the time our survey was in the field gave the provider a score.
Detailed energy provider score breakdown
The table below shows the full results of both our energy customer survey and our in-depth assessment of suppliers’ practices.
Scroll right to see the star ratings from our customer survey, followed by the ratings from our assessment.
Tables notes: Customer results based on a September-October 2024 online survey of 11,984 energy customers among the general public. Customer score: based on satisfaction and likelihood to recommend. Customers rated other service aspects, shown as star ratings. We require 50+ responses to give a rating.
Sample sizes: Utility Warehouse (427), Octopus Energy (2,469), 100Green (191), Ecotricity (115), E (446), Utilita (533), Outfox the Market (86), Co-op Energy (177), Sainsbury’s Energy (159), EDF Energy (1,059), Eon Next (1,328), Ovo Energy (1,041), Scottish Power (817), So Energy (164), Boost (65), British Gas (2,618), Rebel Energy (52), Good Energy (116).
Which? assessment score based on: complaints performance (30%), contacting your supplier (25%), supporting customers who need it (25%), performance against (2023) smart meter targets (10%) and switching (10%).
Total score is a combination of customer score and Which? assessment score. Which? Recommended Providers (WRP) must achieve 70% customer score, receive three stars and above in all survey star ratings and score above average in the Which? Assessment.
If you live in Northern Ireland, see our overview of NI electricity and gas firms.
What makes an energy company the best?
To be a Which? Recommended Provider, a company must be among the highest scorers in our annual customer satisfaction survey, and also score well in our unique assessment of its practices.
Our assessment of practices isn’t new, but this is only the second time we’ve factored it into the total score to give you the fullest possible picture.
Here’s how we calculate the Which? assessment score:
- 25% Contacting your supplier
- 25% support for customers who need it, including those in financial hardship, prepayment meter customers and those with additional needs or language barriers
- 30% complaints performance
- 10% performance against their (2023) smart meter targets
- 10% switching.
We also used customers’ responses on the following to award star ratings:
- Customer service overall
- Ease of contacting
- Usefulness of communications about energy costs
- How accurate your payments are
- How clear your statements are
- Value for money
- Customer communications.
Only customers’ satisfaction with their supplier and how likely they are to recommend it determine the customer score. These additional star ratings give you extra insight into the areas that are important for you.
We also continually review and improve our criteria to make sure we’re assessing the measures most important to customers.
To become a Which? Recommended Provider, an energy supplier must achieve a customer score of at least 70% and receive three stars and above in all survey star ratings. It must also score above average in our assessment of supplier practices.
Find out more about what it takes to become an energy Which? Recommended Provider.
Top-scoring energy companies
Octopus Energy
Octopus Energy earned the highest customer score in our survey, based on real customer satisfaction and likelihood to recommend.
ranked total score of 16 energy suppliers reviewed
Utility Warehouse
Utility Warehouse earned high scores in our behind-the-scenes assessment, scoring highly when it came to helping customers in need and for being available when contacted. But its best prices come in bundles with other utilities.
ranked total score of 16 energy companies reviewed
100Green
100Green has excellent customer service, according to our survey, though it’s not the best choice if you’re on a pre-payment meter.
ranked total score of 16 energy companies reviewed
Lowest-scoring energy companies
British Gas, Ovo Energy, and So Energy have the lowest overall scores in this year’s assessment. British Gas and Ovo Energy both received low scores in the customer survey and the suppliers practices assessment.
The average customer score was 66% this year, an improvement over last year.
Ovo Energy and Scottish Power sat jointly at the bottom of our customer score table, based on our survey results.
Read more about British Gas, Scottish Power, Ovo Energy and So Energy.
Traditional energy companies
Six energy firms dominated the market for decades until the major changes of the past couple of years. Four of the original six still supply more than half of energy customers today – British Gas, EDF Energy, E.ON Next and Scottish Power.
Octopus Energy is now the largest supplier of electricity and the second-largest (after British Gas) for gas. Its dramatic growth in recent years is as a result of it taking on 1.5 million customers from failed supplier Bulb and 1.3 million from ShellI.
Ovo Energy is currently the fourth-largest supplier. It bought SSE Energy Services domestic customers in 2020.
EDF Energy and E.ON Next are the joint-highest-ranked of the traditional big firms this year, with an overall score of 62%.
British Gas has the lowest overall score.
Feeling the pinch with energy bills? Read our tips to cut your energy costs.