Npower boss tells families power is only expensive because 'British houses waste so much energy' The claim was made by Npower chief executive Paul Massara He said suppliers were responsible for only 20 per cent of household bills But regulator Ofgem said the firm's data was 'incorrect and misleading' Shifting blame: Ofgem rejected the claims by Npower chief executive Paul Massara, pictured Gas and electricity bills are high only because households waste so much power, an energy boss claimed yesterday. Saying he wanted to dispel myths and restore trust, Paul Massara of Npower insisted suppliers were responsible for only 20 per cent of a bill. He added: "The actual unit price of energy in the UK is one of the lowest in Europe - but bills are high because British houses waste so much energy. If we can increase the efficiency of the UK's old and draughty housing, we can ensure that annual energy bills are some of the lowest too. The chief executive's claims were immediately rejected by industry regulator Ofgem. A spokesman said: "Their data on network costs is incorrect and misleading." Mr Massara made his comments ahead of a report his German-owned firm publishes today on the energy market. It attempts to shift the blame for higher tariffs from the industry to the Government, saying the cost of green taxes and eco schemes will rise by 272 per cent between 2007 and 2020, driving up energy bills. Npower says the average figure paid by householders through levies on bills under the heading of "Government energy policy and regulation costs" will rise from £75 in 2007 to at least £279 by 2020. By contrast, it says the average cost of supplying a home with energy - gas and electricity - over the same period will actually fall from £514 a year to £408. The company's figures suggest the cost of shifting energy supply away from fossil fuels toward wind, solar and wave power, coupled with schemes to insulate homes are the main reason for rising bills. The cost of building nuclear power stations, which will also be subsidised through bills, will push up the prices paid. The figures are included in an Npower report called "Energy Explained: Inside the Cost of Energy," which is designed to help customers understand why their bills are going up. Burning money: A report by Npower has warned prices will rise still further due to the cost of building nuclear power stations. It claims government policies will push the average household bill to £1,330 in 2020 The company's calculations suggest Government policies, coupled with the fact we live in cold and draughty homes, are largely responsible for a predicted rise in energy bills from £954 a year in 2007 to £1,330 in 2020. Mr Massara said: "At times during the debate on energy, facts have been in short supply, but we urgently need to dispel some myths to restore trust in the energy industry. Suppliers control less than 20 per cent of a bill and I want to shine a light on all the different aspects of energy - particularly to reassure my customers that there is no hidden profit. We made a 3.2 per cent margin in our retail business in the first nine months of 2013. Over the same period our power stations were struggling to recoup the hundreds of millions of pounds in investment required to build them, and made a loss of £59million. 'Misleading': A spokesman for Ofgem said Npower declined to work with them to make the data accurate But the Ofgem spokesman disputed the research: "We offered to help Npower improve the accuracy of their numbers for network charges and it is disappointing that they did not engage fully with us until after the document had been circulated. Ofgem directly regulates the money that network companies can earn through charges. Given this level of certainty we can see that after 2014 network costs per household are expected to remain broadly flat in real terms. It is unclear how Npower can state with any authority otherwise.