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How the scores are worked out

This advice applies to England

We compare energy suppliers' customer service by looking at information from a number of reliable sources.

Information about complaints to third parties

We base our ratings on complaints made to:

  • Citizens Advice Consumer Service
  • the Extra Help Unit
  • the Energy Ombudsman

Information on complaints is only available for suppliers with 50,000 customers or more.

Information about other categories

Information on:

This information is only available for suppliers with 150,000 customers or more.

Information on the Switching Guarantee comes from Energy UK.

How we come up with a star rating

We give energy suppliers a score out of 5 for each category. 1 is poor and 5 is excellent. Then we give them an overall star rating out of 5.

Category score54321
Number of complaints per 100,000 customers 50 or less 51 to 100 101 to 350 351 to 550 More than 550
Customers who found contacting supplier easy More than 75% 70-75% 60-69% 51-59% 50% or less
Customers who found bills easy to understand More than 75% 70-75% 60-69% 51-59% 50% or less
Switches done in 21 days 98% 90-97% 75-89% 50-74% Less than 50%
Signed up to Switch Guarantee Suppliers score a 5 if they’re signed up and a zero if they're not.

Not all categories are equal. Some, like complaints, count more towards the final score than others.

This is because we think the number of complaints a supplier gets is the best indicator of how good their customer service is.

This is how the overall scores are worked out.

CategoryMaximum category scoreCounts towards overall scoreStars towards overall rating
Complaints to third parties 5 stars 30% 1.5 stars
Ease of contact 5 stars 25% 1.25 stars
Billing clarity 5 stars 25% 1.25 stars
Ease of switching 5 stars 15% 0.75 stars
Switch Guarantee 5 stars 5% 0.25 stars
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