Centrica has revealed that operating profit tumbled by 35% after British customers turned down the heating thanks to a milder than usual winter.
The British Gas owner only made £1.03bn (€1.3bn, $1.75bn) in the first six months of the year, compared with £1.58bn it made a year earlier.
Centrica also said extreme weather in America because of the US polar vortex cost it £65m.
"The first half of the year has seen challenging market conditions across the group, both as a result of the weather and reflecting the wider political environment," said Centrica chairman Rick Haythornwaite.
"We have continued our efforts to engage with our stakeholders, particularly our customers, working to restore their trust. And we are taking the steps to position the business for growth in 2015 and beyond."
Meanwhile, Centrica took the opportunity to welcome incoming CEO Iain Conn, who will replace Sam Laidlaw.
"Conn will bring an impressive combination of experience to our business, with deep understanding of the energy sector from a career spanning a variety of roles in one of the world's leading energy businesses. His breadth of knowledge and commitment to customers and safety make him ideally suited to lead Centrica in the next phase of its development," said Haythornwaite.
"Laidlaw has shown exceptional leadership over the past eight years. Under his stewardship, Centrica has achieved greater strength and scale, and a platform for long term growth, delivering returns to shareholders and securing the future energy needs of our customers."