Centrica said profits at British Gas Residential, which has 15.8 million energy accounts in the UK, lifted to £345 million in the six months to 30th June after volumes were boosted by the cool start to the summer.
But the UK's biggest energy supplier also benefited from higher prices. Although it had dropped its standard electricity prices by 5% in January, this did not cancel out a 16% rise in August, when gas bills also went up by 18%.
Consumer Focus has accused utility companies of being quick to pass on rising wholesale costs to consumers but being slow to drop prices when they fall.
Profits at its residential arm are also higher because of weak figures a year ago when it delayed passing on price rises to customers, meaning it was supplying at a loss.
Cold start to the year may have been bleak for us - but it left British gas basking in soaring profits, leading to calls for a better deal
Another energy company another rise in profits. But with significant political pressure British Gas' explanations may not win them friends