So Energy

So Energy is a relatively small energy firm offering fixed tariffs that are 100% renewable. Set up in 2015, it now has more than 300,000 customers after merging with ESB Energy in 2021.

Interestingly, customers have a say in where it sources the electricity from – you can use an online poll on the website to vote for wind, solar, hydro or biomass.

The energy supplier promises that 'customer service is at the heart of everything we do'. To see if that's true, we've quizzed customers and asked them to score the brand on various measures including ease of contacting, usefulness of communications and value for money.

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So Energy score 

We combine the results of our customer survey with an in-depth assessment of companies' behind-the-scenes practices and policies to give you an overall view. 

Take a look at our table below to see our score breakdown for So Energy:

Here's how So Energy's customer and policy assessments break down:

Find out how So Energy compares with other energy suppliers: click to see our full results of the best energy suppliers.

So Energy customer review

So Energy finished with a below-average customer score in our ranking of 17 energy companies, as rated by 11,984 members of the public in the annual Which? customer survey. Its customer score of 63% was matched by Eon Next.

Plenty of alternative providers scored higher in our customer score ranking - the top-three performers were Octopus Energy (78%), 100Green (76%) and Utility Warehouse (73%).

The brand's total score was a particularly disappointing 58%, which is joint-lowest in our survey alongside British Gas and Ovo Energy. Customers rated So Energy three stars for ease of contacting, accurate payments and value for money. 

On a more positive note, customers appear to be happy overall with the usefulness of communications and clarity of statements as So Energy scored four stars for both of these measures in our latest survey.

One customer told us: 'When I have contacted them, they're quick, provide answers and explain things in detail.' Another said: 'I'm quite satisfied with their regular communication.'

Which? verdict on So Energy

• Pros: Customers praise useful communications; good at supporting vulnerable customers in our assessment
• Cons: Low overall score in Which? assessment, customers say it can be slow to respond 

Our So Energy supplier assessment

In September-November 2024, we looked at five aspects of suppliers' business practices and procedures: 

• Contacting your supplier – including how and when you can get in touch, and the quality of self-service help online
• How well they deal with complaints – how many complaints suppliers get and how quickly they resolve them
• Supporting customers who need it – including web accessibility, those in vulnerable situations, in financial difficulty, who use prepayment meters, and those who need materials in languages besides English 
• Switching – how easy it is for customers to switch
• Smart meter targets performance in 2023 –the most recent figures available.

We did this using a combination of the responses to a survey we sent to suppliers and our own assessments.

So Energy ranks near the bottom of our Which? assessment score table with a total score of 52% – only Good Energy scored lower, with 50% overall. E Gas & Electricity (76%), Utility Warehouse (73%) and Utilita (73%) claimed the top three spots.

The brand performed reasonably well in our measure of how well it helps those who need it, scoring 9 points out of 12.

However, the brand also falls short on smart meter target performance, scoring just 2 out of 10 points in this category.

So Energy customer service

Its customers gave So Energy an average of three stars for customer service in our survey – the top performers in this category, Octopus Energy, Utility Warehouse and 100Green, scored five stars.

So Energy scored an underwhelming 5 points out of 13 in our supplier assessment of its customer service. Sainsbury's Energy and EDF Energy also finished with just 5 points. 

So Energy common complaints

In our survey, 6% of So Energy customers said they had made a formal complaint during the past 12 months. The firm scored 8 out of 15 points for complaints in our supplier assessment, which is about average.

We saw some comments related to speed, with one customer writing: 'They can be a bit slow to get me to the right person.' Another said: 'Slow to respond, with recurring issues.'

In our survey, So Energy scored three stars for ease of contact.

Can I join So Energy with a prepayment meter?

No, So Energy doesn't accept customers with prepayment meters at the moment.

Find out whether prepayment energy is right for you.

How sustainable is So Energy?

Sustainability credentials are important when choosing an energy supplier for two thirds of those responsible for choosing their provider. That’s according to our online survey of 3,000 UK adults in August 2024.

So we factor in a range of sustainability criteria in our annual Eco Provider assessment.

Here’s how So Energy fared:

• Proportion of renewable electricity sold to customers: 66.7%
• Doesn't generate renewable electricity. Buys some directly from renewable generators that are subsidised by government.
• So Energy is majority owned by ESB, which operates two gas-fired power stations.
• Trialling a time-of-use tariff for EV drivers.
• Offers installation of solar PV, battery storage, heat pumps and EV chargers.

Find out more about the differences between energy companies renewable electricity and find out how we assessed energy suppliers for sustainability.

Based on information supplied by companies in August 2024 and their most recent published fuel mixes, where available.

Making your home more energy efficient will save money on your bills in the long term and lower your carbon footprint. Get started with our guides to home energy efficiency.