We use cookies to allow us and selected partners to improve your experience and our advertising. By continuing to browse you consent to our use of cookies as per our policy which also explains how to change your preferences.

Other energy companies reviews

iSupply Energy

By Sarah Ingrams

Article 18 of 31

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

iSupply Energy

iSupplyEnergy has sold energy to domestic customers since 2012. iSupply says its mission is to 'rebuild trust in an industry that is long overdue a change.'

iSupplyEnergy is based in Bournemouth, Dorset. Its tariffs have a simple structure, and prices are made up of a fixed unit rate and a daily standing charge. You can only switch to iSupplyEnergy online.

Previously a British-owned supplier, iSupply was bought by European gas and electricity giant Vattenfall in June 2017.

Initially, iSupply only offered electricity tariffs. It began supplying gas as well from December 2015. 

You can find out how iSupplyEnergy's prices compare with your current deal by finding the cheapest gas and electricity with Which? Switch now.

iSupplyEnergy customer score

iSupplyEnergy comes in at 21 out of 31 energy companies rated by 8,761 members of the public in the annual Which? customer survey – the biggest of its kind.

'I rate iSupply because I don't get any problems!'

iSupply Energy customer

iSupply Energy's customer score of 56% is only one percentage point above the national average (55%). Our top scorer was Utility Warehouse, on 79%. Npower was last, on 45%.

iSupplyEnergy score breakdown

The table below shows the breakdown of iSupply's score from our latest survey. Keep reading to find out more about what its customers think of it, and to compare iSupply's fuel mix to the UK average.

Find out how iSupplyEnergy compares with other energy companieswe reveal the full results of the best and worst energy companies.

Which? verdict on iSupplyEnergy

iSupplyEnergy has competitive rates and customers seemed largely happy with its value for money.

'iSupply is cheaper than my last supplier.'

iSupply Energy customer

Customer service seems to have worsened since our last survey, though. One responder said it 'only sends generic answers to questions and gives no follow up.' Another stated that it is 'hard to contact them'. 

The energy supplier is an online-based company. Although its website is simple to use, iSupply doesn't offer any live chat facilities. 

iSupply has dropped significantly in ranking since our last survey - going from eighth spot to 21st. This pushes it into the bottom 10. 

It could be that the way iSupply handles complaints is affecting its overall score. It had one of the worst rates for complaints resolution in 2017. Only 3% of complaints received were resolved within two workings days and no more than 76% were fixed within eight weeks. These were some of the worst rates of all the energy companies investigated. 

The best energy firms resolve close to 100% of their complaints.

Not everyone is unhappy; many customers feel like they are getting an OK service and don't have too many issues to comment on. 

'No real problems, but not overly helpful.'

iSupply Energy customer

In order for a company to be nearer the top of our table, its customers need to extremely satisfied with the service they're getting. 

Pros: It offers competitive electricity and gas tariffs

Cons: Needs to address how it solves complaints, a few customers felt it could be better for helping them save energy

iSupplyEnergy electricity sources

iSupply in the news


March: iSupply increased the price of its variable energy tariff by 7%. This means that customers will see £76 on average added to their annual bill.


June: iSupply announced that it had been acquired by Vattenfall, the Swedish energy group. Vattenfall is one Europe's largest generators of renewable energy and they supply over 7m gas and electric customers in Northern Europe. 

iSupply will continue to supply its more than 120,000 gas and electricity customers in the UK as an owned subsidiary of the energy company. 

Fed up with high bills and slack customer service? Use Which? Switch to find the cheapest gas and electricity.