British Gas owner Centrica has said overall profits rose by a fifth in the first half of the year, despite losing 505,000 energy accounts.
Gas prices are to rise again
The firm, which last week revealed domestic energy bills were to rise by 14.2%, also announced it planned to sell its One.tel telecoms business.
Centrica also revealed CEO Roy Gardner was to step down next year, to become chairman of catering group Compass.
Overall profit was up 19% at £967m, with strong gains from gas production.
Analysts believe Centrica could earn more than £200m from the sale of Onetel.
Despite shedding more than half-a-million accounts, Centrica said "more recently the rate of losses has slowed significantly".
But the firm, which supplies power and gas to 17 million domestic UK users, warned operating profits would be reduced in the second half as rising wholesale energy prices took effect.
"The overriding challenge for the entire industry in the second half of the year will be the level and volatility of wholesale commodity price," the company said.
Chief executive Sir Roy Gardner said the firm understood the effect of rising energy prices on consumers.
He also said provision was being made for the company's most vulnerable customers.
But it remained essential to "maintain the appropriate level of profitability to enable us to invest in sourcing the future energy requirements for our customers".
Shares in Centrica have risen in recent weeks amid speculation it may be a takeover target. However in early trade in London they slipped 0.29% to 258.50 pence.