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The best energy supplier in the UK in 2021

Included in this guide:

best energy supplier 2021: rows of houses
(Image credit: Getty )

Wholesale energy cost increases mean there are currently fewer cheap deals available in the market, and now may not be the best time to switch energy supplier. 

The best energy suppliers in the UK offer great value for money - and outstanding customer service too. There are many reasons why you might want to switch energy provider. Maybe you're looking for the cheapest energy supplier to help reduce your bills (and many people are, faced with increased bills this winter thanks to the exploding cost of gas). Perhaps you want to switch to a greener tariff, or get a smart meter. It might be that you just aren’t happy with your current supplier. 

Whatever your circumstances, we can help you find the right provider - and the right tariff too. In this guide, we've created a ranked list of the best energy suppliers in the UK. We assessed each provider against key criteria including pricing, tariff options, their green credentials, the quality of their customer service, and more. We also looked at thousands of user reviews to see which were the most popular providers, and why. 

Once you've chosen the right energy supplier for your home, it's a good idea to run an energy price comparison. This will show you the best energy deals in your area, so you can be sure you're getting optimum value for money. Here's our pick of the best energy suppliers in the UK.

The best energy supplier in the UK right now

best energy supplier in the UK: Octopus

(Image credit: Octopus Energy)

1. Octopus Energy

The best energy supplier in the UK overall

Tariffs: various
Exit fees: none
Green electricity: 100%
Green gas: N/A
Carbon offset: 100% on the 'Super Green' tariff
Reasons to buy
+Great customer service+Very good value for money+Could pay you to use electricity+Invests heavily in green energy
Reasons to avoid
-Outfox the Market has cheaper tariffs  

Octopus Energy consistently tops the industry's best energy supplier lists. Since launching in 2016, the company has looked to made good on its promise to provide greener and cheaper energy - and won numerous awards in the process. 

In the last few years, Octopus has built a solid reputation for quality customer service. It was one of the only providers that continued to offer support across multiple contact channels during the global pandemic, which partially explains why the company scores so highly on independent user review site Trustpilot. Octopus boasts an average of 4.8 out of 5 stars from over 60,000 customers (August 2021), and an impressive 90 per cent rating of excellent. 

It's affordable, too. According to Energy Helpline data, Octopus's Fixed tariff is one of the cheapest around: it's £3 a year less than Bulb - our second best energy supplier - and over £200 per year cheaper than the average Big Six plan. We also like how Octopus continues to innovate and provide new flexible deals for customers. Its Agile Octopus tariff, for example, enables you to save more money when wholesale prices fall, and if the grid receives excess green energy - as it has done regularly - users can even be paid to use electricity. 

This winning combination of Octopus’ commitment to sustainability, quality customer service, the fact that it offers some of the country’s cheapest green energy tariffs, and the company's progressive approach to research and development, is why it takes our top spot as the UK’s best energy supplier. 

best energy supplier: Outfox the Market

(Image credit: Outfox the Market)

2. Outfox the Market

One of the cheapest energy suppliers

Tariffs: multiple
Exit fees: £30 per fuel on some tariffs
Green electricity: 100% renewable electricity
Green gas: N/A
Carbon offset: N/A
Reasons to buy
+Very cheap tariffs+Committed to green energy+Great customer service
Reasons to avoid
-Complaint handling could be better-Prepayment meters not supplied

Outfox the Market claims one of its main aims is to help customers save on their energy bills, and it consistently offers some of the cheapest green energy deals on the market. The company has a strong average rating of 4.5 on Trustpilot from over 29,000 user reviews (August 2021). Over the last year customers have reported good customer service - this hasn't always been the case - with lots of people also commenting on the value for money of its tariffs, and the speed of its live chat facility.

Bear in mind that Outfox the Market doesn't supply prepayment meters. The website is quite basic too, with a quirky style that might not be to everyone’s taste. Nevertheless, it remains an excellent option if you want an affordable green supplier with a simple setup..

best energy suppliers: Bulb

(Image credit: Bulb Energy)

3. Bulb Energy

An all-round great energy supplier with competitive prices

Tariffs: one, variable
Exit fees: none
Green electricity: 100%
Green gas: 10%
Carbon offset: 100% carbon neutral
Reasons to buy
+One easy-to-understand tariff+Biggest buyer of green gas+18% cheaper some Big Six plans
Reasons to avoid
-Prices can change

Bulb Energy has three values: ‘simpler, cheaper, greener‘. The company is recognised as one of the UK’s biggest green energy suppliers, and buys all its energy from renewable generators. Its single tariff uses 100 per cent green electricity and 10 per cent green gas - the rest is offset, making it fully carbon neutral. 

Bulb's one tariff is designed to take the confusion out of choosing a plan. It's a variable plan, which means prices can increase if wholesale prices go up, but it's typically cheaper than most other energy suppliers. According to Energy Helpline, the average UK household will pay £890 per year with Bulb, which is over £200 cheaper than a typical Big Six tariff.

Bulb’s customer service is also excellent. It offers an online community hub for customers to share questions and experiences, alongside helpful online chat options and a phone service, which continued to operate during the pandemic. If you're looking to simplify your energy options, and want value for money, Bulb is one of the best energy suppliers in the UK. Plus, if you refer a friend you'll both receive up to £50 each in credit as a thank you. 

best energy supplier: So Energy

(Image credit: So Energy)

4. So Energy

Cheap, easy to use and green - just watch out for the early exit fees

Tariffs: various fixed rates
Exit fees: £10 for duel fuel, £5 for single
Green electricity: 100% renewables
Green gas: N/A
Carbon offset: N/A
Reasons to buy
+Some of the cheapest fixed tariffs+Can choose energy sources
Reasons to avoid
-Has early exit fees-Only supports second gen smart meters

So Energy is relatively new, but this green energy supplier is continuing to grow in popularity. The company’s pledge to ensure its tariffs will "always be one of the most competitive on the market" means that there are often very good deals to be found, with one of the cheapest being a competitive £853 per year. 

One notable area where So Energy differs from other providers is that customers can vote and choose where the supplier gets its renewables from, which regularly varies the green fuel mix. Another high scorer on Trustpilot, So Energy also boasts 4.3 out of 5 stars, albeit from a lower pool of 6,500 reviews (August 2021). That's largely thanks to its excellent customer service - and the company gave regular coronavirus updates last year - as well as its smart, easy to use website, and fast switching process. Like all the suppliers here, it's signed up to the Energy Switch Guarantee, which gives you added peace of mind.

Bear in mind you will be charged exit fees if you leave your contract early. However, these are lower than the £30 per fuel costs you typically get at other suppliers. We think So Energy is an excellent green supplier that will be a good fit for anyone looking for an ethical and straightforward choice.

best energy supplier: OVO Energy

(Image credit: OVO Energy)

5. OVO Energy

One of the UK's biggest energy suppliers

Tariffs: various
Exit fees: £30 per fuel for some tariffs
Green electricity: 50%, can be upgraded to 100%
Green gas: can upgrade to 15%
Carbon offset: can upgrade to 100%
Reasons to buy
+Very popular energy supplier+A choice of green energy tariffs+Rates well on customer satisfaction
Reasons to avoid
-More expensive than some

From its humble beginnings in 2009 as a small independent firm, OVO Energy has grown substantially, and recently acquired SSE to become one of the UK’s biggest energy providers. It's dedicated to providing green energy and becoming a carbon net zero business by 2030. 

OVO Energy offers a variety of tariffs, and consumers have the option to upgrade each to become 100 per cent renewable. However, its tariffs are a bit more expensive than those from the likes of Octopus and Bulb, with the most popular two-year fixed tariff costing an average of £1,064 per year. 

This is another company that’s big on technology. OVO offers extra smart meter and electric vehicle (EV) tariffs, and boasts a slick website, app and online account management facilities. However, unlike Pure Planet, OVO does also offer a customer service phone line, which is open from 8am-6pm and offered additional COVID-19 updates during lockdown. As such, it has a relatively strong Trustpilot score of 4.2 out of 5, from 40,000 user reviews (January 2021).

Find the best energy deal for your home

Find the best energy deal for your home
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Richard Hart

Rich is a freelance copywriter and content strategist with over 10 years' experience. His career has seen him work in-house and in various agencies, producing online and offline content marketing campaigns and copywriting for clients in the energy industry.