'Big six' energy supplier SSE has told MPs that it expects to pay Â£1.5 million to its customers in compensation.
The company was fined Â£10.5 million by Ofgem for mis-selling earlier this month.
It previously revealed that it had set aside Â£5 million for compensation.
SSE's deputy chief executive, Alistair Phillips-Davies, told MPs on the Energy and Climate Change Committee that the company would be offering compensation to customers that lost money as a result of the mis-selling.
Mr Phillips-Davies said: "If any customer feels they've been disadvantaged since October 2008, they will be compensated."
He stated that SSE was paying, on average, an amount of between Â£65 and Â£70 per customer in compensation. The deputy chief executive also said that around 23,000 customers may have been affected, adding: "if you multiply that up, that makes about a million and a half pounds."
In a bid to make customers aware of the possible compensation SSE has placed advertisements in national newspapers. It's also written to customers.
Speaking to the MPs, Mr Phillips-Davies added that SSE's training and audit procedures had been changed, and that it had ceased doorstop selling contracts back in 2011.
SSE, a Green Deal approved provider, was just one of the eight energy companies being questioned by the MPs.
The Green Deal is a government policy that provides homeowners with the funding they require to make energy-saving improvements - such as the addition of a new gas boiler. Rather than paying the money upfront, homeowners can pay the costs back through their energy bills - much like a loan.
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