The survey, carried out by Which?, found 93% of calls made offered the cheapest tariff, up from 75% last time. However there were also cases of the wrong deals being offered and vital details like exit fees not being mentioned upfront.
Scottish Power and Southern Electric scored highly in the tests, with British Gas and npower faring worst overall. npower also failed to mention exit fees in half the calls made.
According to energy regulator Ofgem around a quarter of customers call energy companies to check they are on the best deal, rather than going online.
Commenting on the findings Thomas Lyon, energy expert at uSwitch, said: “There are some welcome improvements here and it’s good to see that more consumers are able to get a better deal from calling their current supplier. However, there’s a difference between getting a better deal, and getting the best deal.
“They could still be missing out as their supplier will only be able to tell them about their own tariffs – more than likely there will be another supplier offering a more competitive deal. This is why it’s so important for consumers to get an independent and impartial comparison across all the market – this is the only way of being sure that you are getting the best available deal and the only way of knowing how your supplier really stacks up.
“By simply accepting a better deal with your current supplier you could be losing out – there is currently almost £250 a year difference between the cheapest and most expensive tariffs on the market, so it really does pay to find out more.”