'The cheapest unit of energy is the one you don't use': Boss of npower's YouTube message to customers as firm hikes energy prices by 10% Electricity tariffs will rise by 9.3%, gas prices by 11.1% from December Company blames rising fuel costs and meeting government schemes Move comes after 9.2% rise by British Gas and 8.2% increase by SSE David Cameron says he 'understands why households are angry' Ed Miliband: 'We've got a PM standing up for energy firms. We need action By Tamara Cohen and Simon Tomlinson The boss of npower today risked a furious backlash from hard-pressed families after telling them to use less energy as he hiked prices by more than 11 per cent over the winter. The firm hit its three million customers with a 9.3 per cent rise in electricity prices and an 11.1 per cent increase in gas tariffs from December in an announcement today. The hike will mean an average dual fuel customer's bill rises by £137 a year, from £1,323 to £1,459. Controversial: Paul Massara delivers a message on YouTube advising customers to cut back on their energy usage as the company announced rises of up to 11.1 per cent from December In a video posted on YouTube today, chief executive Paul Massara blamed the rises on the higher cost of delivering power to homes, meeting Government schemes and rising fuel costs. He advised families to cut back on their energy use if they want to save money. Mr Massara said: 'It may be a cliche, but it's true: the cheapest unit of energy is always the one that isn't used. And we can offer plenty of advice of how you can cut down on your energy usage. He also invited customers to ring the company if they are worried about their bills, adding: 'We're here to help.' Ministers were today forced to defend a deal with French power giant EDF Energy to build the £16billion plant at Hinkley Point in Somerset which will mean customers paying double the current rate for electricity. Energy Secretary Ed Davey said the controversial deal was essential if Britons want 'to be able to keep watching the television, be able to turn the kettle on...to keep the lights on'. David Cameron hailed the deal as 'a very big day for our country' and boasted that Hinkley Point C would be the first of many new nuclear power stations in Britain. EDF will get a guaranteed price for the electricity it generates for decades, which will be added to household bills when the plant is up and running in ten years" time. But ministers argue that the plant will save consumers money compared with building offshore wind farms or importing gas from abroad. Last week, British Gas faced a torrent of abuse from Twitter users after hosting an online question and answer session on the social media website three hours after it announced a 9.2 per cent price hike. The third of the so-called 'Big Six' to drive through bill increases, npower also raised tariffs by 8.9 per cent last November. It insisted more than 500,000 customers on fixed contracts will not be affected. Bill hikes will add more upward pressure to stubbornly high inflation, which currently stands as 2.7 per cent, far outstripping average wage growth of just 0.7 per cent. It follows a much-criticised 9.2 per cent price rise by British Gas for its 8million customers. SSE raised prices by 8.2 per cent a week earlier. The other three major suppliers - E.On, EDF and Scottish Power are widely expected to bring in similar rises in the coming weeks. Asked for the Prime Minister's response to npower's announcement, David Cameron's official spokesman said: 'He very much understands why households are angry. Nobody wants to see higher bills. Responding to Archbishop of Canterbury Justin Welby's call for energy companies to be 'conscious of their social obligations', the spokesman added: 'This is a major area of public concern, so it is hardly surprising that the Archbishop of Canterbury would highlight the issue.' Ed Miliband said: 'Neither the energy companies, nor the government want Labour's price freeze because they are content for prices to carry on rising at 10 per cent a year. 'It's another day, another 10 per cent price rise in energy. We've got a Prime Minister who is standing up for the energy companies, not hard-pressed families. That's why we need Labour's price freeze. 'The reason prices are going up is because you've got a broken market and you've got companies that are overcharging people. 'Week after week, we are seeing company after company putting their prices up and we've got a Prime Minister standing by. That's why we need action.' Mark Todd, director of price comparison service energyhelpline, said: 'This is devastating news and is proof to cash-strapped consumers that customer loyalty reaps no benefits. The truth is that there is nowhere to hide from the energy hikes and more suppliers are set to follow suit. In a statement earlier in the day, Mr Massara, said: 'I know that any increases to household bills are always unwelcome, and this is not a decision that we have taken lightly. We will continue to take steps where we can to reduce the impact of the external influences on energy bills. Graph showing the impact on energy and climate chance policies on our gas and electricity bills (Source: Energy and Climate Change Committee) We only aim to make around 5 pence in every pound (5%) in our retail business which we feel is a fair return for delivering reliable energy to consumers and for the risks that we bear. 'We understand that although the Labour Party's proposed price freeze may appear superficially attractive it will not lead to lower sustainable prices going forward because it doesn't cut the growing costs of supplying energy. Only 16% of the bill is under our control and imposing price controls discourages investment, increases uncertainty and ultimately leads to higher prices. npower is committed to working with consumers, government and industry to deliver a modernised energy market which is affordable for customers and has a lower CO2 content. It is therefore essential that we have an open and honest conversation with customers about how they can take control of their bills and reduce energy consumption. Npower's announcement came as Britain sealed a deal with French energy EDF to build the first nuclear power station in a generation at Hinkley Point in Somerset, after lengthy wrangling over taxpayer subsidies. Consumer bills have soared by £300 in three years under the Coalition and the firms which supply 98 per cent of customers have enjoyed a £3.3billion windfall in profits before tax. Ministers have told consumers to save money by switching suppliers online, but another year of coordinated rises in bills will fuel criticism the market is monopolised by the six power giants. The Archbishop of Canterbury Justin Welby has weighed into the debate saying energy firms have a moral duty to "behave with generosity" to struggling families "and not merely to maximise opportunity." Archbishop Welby, a former oil executive who also has experience of living on a low income as a vicar in Coventry, called on suppliers to justify their bill rises. He said: "I do understand when people feel that this is inexplicable and I can understand people being angry about it because having spent years on a low income as a clergyman I know what it is like when your household budget is blown apart by a significant extra fuel bill and your anxiety levels become very high. It comes as senior Tories were drawing up plans to reduce green taxes on energy bills to help hard-pressed consumers, in the face of staunch opposition from the Liberal Democrats. The government are "on the back foot" over the issue after Ed Miliband announced he would freeze energy bills for 20 months if Labour wins the next election, one Tory said. Their plans include allowing more time to insulate the homes of vulnerable customers, and meet targets to cut carbon emissions, which together cost a typical customer £112 a year rising to £286 by 2020. They would also review the Carbon Price Floor, a much criticised green tax on power firms which is passed on to customers, and cut the cost of distribution of gas and electricity which the MPs say is run on a system of "regional monopolies." Lib Dem energy secretary Ed Davey is resisting any attempts to cut the levies, or change the timetable for them, claiming that they will help to reduce bills in the long-run. Nick Clegg also ordered energy firms to justify the latest "eye-wateringly high price hikes." Energy bills and on the way up - but you could save up to £300 by switching. Providers offer their cheapest rates via online tariffs, so if you're ready to switch, it will certainly pay to do so. But suppliers tend to charge more for electricity to those customers who live in their 'home' region - the areas where they enjoyed a monopoly before energy deregulation. So switching away will almost always save you money. Prices are different all over the country and the cheapest supplier for you will depend where you live. You only need to be interested in the tariff that is going to be cheapest where you live, so do your own comparison to find the best price. By Amy Andrew