The consumer watchdog said without having the TCR explained, customers will not be able to accurately compare energy deals.
As part of its Fair Energy Prices campaign, Which? phoned 13 suppliers six times each, asking them to explain the TCR. Only Eon and Npower gave an accurate description but only in two of the six calls they each received.
The TCR provides an illustrative cost for an energy tariff based on medium gas and electricity usage, and is intended as a guide to help consumers compare tariffs.
Which? executive director Richard Lloyd called on the energy suppliers to adopt simple pricing, “similar to petrol pump displays”, so that consumers can find the best deal.
Energy UK, the trade association for the energy industry, said energy deals cannot be compared with petrol pump price displays because of the factors that affect its costs.
“These include the customer’s location and government legislation which applies to some companies and not others,” it said.
Ofgem stated it is monitoring energy supplier’s compliance with its rules closely. “The TCR provides for a quick at a glance view of prices across the market. If consumers want a personalised estimate based on their own consumption suppliers must also provide this.”
Responding to the Which? report, Scottish Power said it includes a leaflet in its customer bills, “which clearly explains the tariff comparison rate and outlines how it is calculated”.
Npower said its advisors are fully trained to make sure customers are on the best deal and that it also holds “regular refresher training sessions.”