Spark Energy, the supplier which recently ceased trading and has since been acquired by Ovo, was the worst energy company for call waiting times, according to research from Which?.
It revealed that Spark Energy left customers stuck on hold for an average of 27 minutes 21 seconds – a call length that would potentially cost £15 for someone using a mobile.
The supplier did however have a 25 second average waiting time on its live chat feature, although the service was unavailable on six out of 12 attempts.
The investigation involved making more than 450 phone calls to a total of 38 gas and electricity suppliers as well as testing live chat and email services.
As a result “huge” variations in how long customers were kept waiting to speak to a member of staff were found.
Energy customers, the research found, wait an average of almost half an hour on hold while on the phone to their supplier.
Utilita for example left its customers waiting for an average of 24 minutes 19 seconds and had the longest single call waiting time of 72 minutes 40 seconds.
This supplier answered live chat enquiries in 93 seconds on average but was unavailable on seven out of 12 occasions.
A spokesperson from Utilita said in response: “We are constantly reviewing our processes and always strive to improve our performance.
“This is a busy time of year as customers start using heating moving in to autumn, and that peak has been a bit later than usual this year.
“We work with some of Britain’s most vulnerable households and are constantly looking to make our customers lives’ easier with additional services such as live chat and our new app which includes the industry-leading power up function, allowing thousands of vulnerable customers the option to add a small top-up credit to their meter themselves – and set their own repayment terms for their interest-free vend.”
The spokesperson added that the app is proving very popular but a number of people are asking for help to set it up for the first time, resulting in a spike in calls, something the company believes will be temporary.
Out of the big six, five kept customers waiting for around 10 minutes or longer on average.
Npower was the worst out of these, with the average waiting time of 20 minutes 31 seconds and was the worst supplier for live chat response times – taking more than 17 minutes on average before a customer service adviser responded.
An Npower spokesperson said: “Over the last few months we’ve seen a significant increase in customers calling our centres.
“To make sure our customers can contact us more quickly, we’re currently recruiting an extra 140 customer facing employees in the North East of England.”
The supplier was followed by SSE and Eon, which both took more than four minutes on average – although researchers found Eon’s live chat function was unavailable on ten out of 12 attempts.
Scottish Power was the best out of the big six, with an average call waiting time of three minutes 29 seconds.
Small supplier Affect Energy had an average time of 10 seconds while So Energy had an average of 21 seconds, these two were the best performers overall.
For companies which did not offer live chat, researchers contacted them by email or online forms instead.
Both Engie and Economy Energy failed to answer any of the 12 enquiries Which? made within two weeks.
Eight firms – Solarplicity, Octopus Energy, Co-Operative Energy, Affect Energy, Sainsbury’s Energy, Flow Energy, So Energy and Tonik Energy – responded to emails or online forms within a day, on average.
Alex Neill, Which? managing director of home products and services, said: “As if regular price hikes aren’t bad enough, customers of some energy companies are facing infuriating waits just to get through to a customer service adviser on the phone.
“No one should have to put up with shoddy customer service and rip-off deals. If your current supplier is constantly leaving you in the lurch, you should switch and potentially save almost £400 a year.”