Help with energy costs has been extended for all households, but at a less generous level, meaning millions will still face higher bills.
The bill for a typical household will rise to £3,000 in April, from £2,500 now, Chancellor Jeremy Hunt announced.
Without this help, average bills would have gone up to about £3,740, according to consultancy Cornwall Insight.
Mr Hunt also announced additional cost-of-living payments for the most vulnerable.
He said this meant an extra £900 for low-income households on means-tested benefits, which is £250 more than the equivalent payment this year.