However, the company has also stated that customers on fixed-term tariffs will not be affected by the increases, while it is also set to offer people over 70 free home insulation grants in an effort to help them reduce energy costs.
Phil Bentley, managing director of British Gas, added that the firm's efforts to become more energy efficient were putting pressure on its energy prices.
"As Britain's greenest electricity supplier, we are investing in further lowering our carbon emissions," he said.
"However, this also comes at an increasing cost for all. Ultimately, the best way of reducing energy bills is to make our homes more energy efficient."
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