Energy Supplier Complaints

In January 2026, the latest Ofgem data on complaints from Q3 2025 showed that energy supply companies averaged 1,027 complaints per 100,000 customers (a 30% improvement in one year). However, the rate of complaints is quite different depending on the size of the supplier.

Notably, large suppliers (e.g. British Gas, EDF Energy, Eon, OVO, Octopus Energy, Scottish Power) improved their complaints rates by 30% in one year, with the most recent data indicating around 1,026 complaints per 100,000 customer accounts. In contrast, the complaints for medium suppliers (e.g. Utilita, So Energy, Utility Warehouse) have worsened by 33% in one year, with Q3 2025 data indicating 1,321 complaints per 100,000 customer accounts. Small energy suppliers have the best complaints rates - with only 233 complaints per 100,000 customers on average during the same time period.

The Ofgem data shows that small suppliers have the lowest complaints rates, on average, followed by large suppliers. Medium suppliers have posted the worst complaints rates.

Another important metric is how quickly complaints are resolved. Generally speaking, just over two-thirds of complaints are resolved by the energy company by the next working day. Historically the larger companies were better at this metric; but most recently, it's the small companies that are quickest at resolving complaints.

Best and Worst Complaints Rates

The level of service varies quite dramatically from company to company, with the worst energy suppliers having complaints rates over 10X that of the suppliers with the lowest complaints rates (see best energy suppliers).

For example, Outfox, E, Green Energy UK and Ecotricity (all small companies) had the lowest complaints rates in Q3 2025, all with under 130 complaints per 100,000 customers. However, the company with the worst rate was also a "small" supplier (Tru Energy, with 2,230 complaints per 100,000 customers).

With the exception of Scottish Power, all other large suppliers have improved their complaints rates in the past year.

Best and Worst Complaints Resolutions

How quickly do energy companies resolve customer complaints? Many issues are simple to fix - perhaps a question about a bill or meter reading - and should be taken care of with a simple call to customer services.

In previous years, the small companies were generally best at quick complaint resolution, but recently this has shifted and now the lowest complaints resolution stats hail from small companies (e.g. Outfox, Green Energy UK, Ecotricity and Tru Energy resolved complaints by the next working day less than 35% of the time.

The best for quick complaints resolution was Utility Warehouse, which resolved 83% of complaints within one working day.

Keep in mind that even when a high proportion of customers have an issue, if problems appear to be resolved quickly they may not be something to worry about. And many quickly-resolved issues relate to set up.

Top 5 Complaints

What are the most common complaints people have with their energy supplier? We took a look at the top 5 most common complaints from the Big Six energy suppliers to see what goes wrong for customers most often. The top 5 most complaints from the Big Six providers were:

• Billing and meter readings: This metric captures how easy or difficult it is for customers to understand their bills (e.g., layout and content of the bill, amount outstanding, etc.).

• Metering: Metering complaints can arise when a technician is late or unable to attend a home visit appointments to read or change a meter (e.g., install a smart meter), whether due to bad weather, road traffic delays; or if they don't have the right equipment to finish a job.

• Payments: Payment complaints can relate to direct debit or prepayment meter payment queries, such as the size of the bill, the method of payment, a change in consumption or personal circumstances, or following a price change.

• Customer Service: This metric captures customer service experiences when speaking with call centre agents about services and products.

• Change of Supplier: Complaints related to setting up new accounts, for instance when a customer switches provider.

The most common gas and electricity supplier complaints vary from company to company, however. Energy suppliers are supposed to list their top 5 complaints on their websites for customers to see. While not all companies do this, the big companies do - here are the top 5 complaints for some of the largest energy providers so you can compare:

How to complain about your energy supplier

To make a complaints about your energy supplier, call, email or go to their website to find an online complaints form. Below we've listed complaints numbers and email addresses for dozens of popular UK energy suppliers, listed by alphabetical order:

If you have complained to your energy supplier and you're unhappy with their decision or you haven't been given a decision in 8 weeks, you can make a formal complaint to the energy ombudsman.

Additionally, you can contact Citizens Advice at any point in the complaints process - they have lots of information on their website and even have a helpline you can call for assistance (08082231133).

Methodology

NimbleFins analysed the following complaints data from Ofgem, reflecting Q3 2025, which can be found here.

• Domestic complaints resolved by end of next working day (for small, medium and large companies)

• Domestic complaints received per 100,000 customer accounts (for small, medium and large companies)