Washout summer 'adds £1bn to energy bills' Monthly gas bills normally fall drastically in the summer months, from an average of £49.70 in May to just £16.80 in July and August, according to energyhelpline.com, the price comparison service. But this year usage is continuing at May levels into the summer, the company estimated. "Effectively the current weather means that our summer bills could be more like typical May bills - that is, £50 rather than £17 for heating and hot water," said Mark Todd of energyhelpline. An extra £33 on the bills of every one of Britain's 26 million households would mean an extra £858m per month on the country's bills for heating and hot water. Men were slightly more likely to switch the heating on, the research found, with 51pc of men and 49pc of women saying that they had reached for the thermostat. There were more marked regional differences, with 93pc of respondents in Northern Ireland saying they had used the heating, while just 38pc in London followed suit. David Bond, npower's customer marketing manager, said: "The weather over the last couple of months has seen many people reaching for the heating controls so it's important that heating systems are well maintained so they are ready to spring into action when needed."