Bord Gáis Energy contributed £23m (€32.7m) to the bottom line of its new parent company Centrica in the first six months of the year.
The utility had revenues of £400m (€569.5m) during the period, with Centrica saying it had performed well since being acquired a year ago for €1.12bn.
The number of residential customer accounts was down 1% to 600,000 while the company also cut prices in March; but this was offset by higher consumption due to colder-than-usual weather in the country.
Centrica’s main subsidiary British Gas was also boosted by colder weather, reporting a profit of £528m for the first half of the year, more than it made in the whole of 2014.
Profits at the group as a whole were down, however, falling 3% to £1 billion.
The company has also announced plans to cut 6,000 posts would be cut across the group, around 10% of its workforce, although 2,000 new jobs will be created so the net loss will be 4,000.
The cuts follow a strategic review which is aimed at delivering savings of £750 million over five years.
