Bulb said it will increase the price of electricity but lower the price of gas to reflect changes in the cost of supplying energy.

Electricity will rise by £53 from 18 October due to a rise in wholesale energy and network costs. It said wholesale costs are up 28% since April.

However, gas rates have actually come down a little, meaning Bulb customers will see a £2 fall in bills from 1 October.

For a dual fuel energy customer, this means an overall rise of £51 a year. But Bulb said even after the changes, bills will be £76 a year cheaper than regulator Ofgem’s price cap:

• Bulb’s credit tariff is increasing from £915 to £966; a £51 increase that is £76 below the price cap of £1,042
• Bulb’s prepay tariff is increasing from £998 to £1,025; a £27 increase that is £45 below the price cap of £1,070.

New customers who switched to Bulb from 14 September will pay the new rates.

It added that for its 1.7 million customers, it doesn’t charge exit fees so they can leave at any time without penalty.

Hayden Wood, Co-founder and CEO of Bulb said:“At Bulb, we’re committed to pricing fairly and transparently. That’s why our tariff reflects the true cost of energy, so members know they are always on our best available deal.

“Overall costs of supplying homes have gone up significantly, and we’ve held off passing on the cost for as long as possible. As soon as the price of supplying energy falls again, we’ll gladly pass on the savings to our members – when costs fall by more than £20 per year, so will our tariff.”

Will Owen, energy expert at Uswitch.com, said: “There is never a good time to see energy prices rise, but customers are likely to feel this extra cost even more as winter approaches and electricity use increases.

“Bulb Energy has blamed growing wholesale prices for the increase, and we will be watching to see how other suppliers might react as the energy market continues to rise from historic lows in April.

“Savvy consumers should act now and look online to see what energy deals are available to them. Customers can save an average of £387 by switching to a better energy tariff.”