The German group is the latest energy supplier to reveal how much it cashed in from the unprecedented freeze that forced shivering householders to spend extra money keeping their homes warm.
Npower, one of the UK's big six energy suppliers with 6.5 million gas and electricity accounts, put up gas tariffs by 8.6% last November shortly before the onset of the bitterly cold spell.
UK gas supply volumes increased by 12% over the first half of the year, pushing revenues for RWE up by 138 million euro (£118 million) to 1.34 billion euro (£1.15 billion).
But the company said operating profits from the UK were down 6% to 206 million euro (£176 million), blaming new regulations forcing energy companies to simplify tariffs and pay for energy efficiency measures in customers' homes.
"However, price adjustments cushioned the aforementioned burdens," the group said.
Meanwhile UK electricity revenue was down 4% to 2.94 billion euro (£2.52 billion) on falling volumes supplied to industrial and corporate customers - blamed on competition and economic conditions.
Chief executive Peter Terium said the subsidy-driven renewables market had made many power stations unprofitable to operate.
He said the group was reducing capacity, shutting down coal-fired plants and looking at further closures.
RWE made a 25 million euro (£21 million) loss from its UK power generation activities as earnings from this sector also fell in western Europe. The company said they were hit by falls in carbon dioxide emissions allowances.
During the period, the group ceased operations at its coal-fired power station at Didcot, Oxfordshire, which did not satisfy European emissions requirements.
Meanwhile the oil-fired power station at Fawley, Hampshire was closed for economic reasons, the company said.
RWE added that Tilbury power station, which was converted from coal-fired to a biomass station in 2011, ceased generation this month due to emissions regulations.
It said it would have to invest heavily to continue operations but long-term profitability was in question and it was considering options for the site including a sale.