Their research suggested workers nationally faced a £1.9bn surcharge due to the new working arrangements triggered by the coronavirus pandemic.
It comes after the government performed an about-turn last month when they urged all office employees to work from home if they could as coronavirus cases surged.
Boris Johnson had led calls for staff to return to the workplace in a drive to support the economy amid concerns cafes and other businesses that rely on office worker footfall were facing ruin.
But as coronavirus cases rose, Mr Johnson said: “We are once again asking office workers who can work from home to do so.”
Energy Helpline research showed that the total winter fuel bill for a person working from home five days a week would come to £707.93 - 18 per cent more than the average winter dual fuel bill for the previous year. Experts said bills would rise by £107 as a result.
That would drop to a 3.6-per-cent rise in energy bills for an employee working from home just once a week.
Energy Angels, an advice and comparison service, urged those who were worried about increasing energy prices whilst working from home to check they were on the cheapest tariff.
Peter Smith, of fuel poverty charity National Energy Action (NEA), said the change in working habits could push people into debt and called on the government to provide more support for the poorest households.
He told The Observer: “This could lead to increased affordability issues, more energy debt or even energy rationing, which can be dangerous all year round but particular during colder weather.”
Mike Clancy, the general secretary of trade union Prospect, told the paper: “Full transparency about the risks and costs of working from home is essential, and dialogue with trade unions is the most effective way to get this right.
“The challenge is to ensure that the post-pandemic recovery builds on the benefits of flexible working rather than hardwires in inequality.”
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