Nearly 6 million families stuck in poorly insulated homes face paying £320 more on their bills when the energy price cap rises next month.
The Resolution Foundation warned that Brits are facing a "leaky homes surcharge" when energy bills rise due to the longstanding failures to properly insulate houses.
Millions of households will see their energy bills hiked within weeks, as those on default tariffs paying by direct debit will see an increase of £693 from £1,277 to £1,971 from April 1.
Homes are awarded energy performance certificates (EPC) which rank how energy efficient a building is on a scale from A to G.
Families living in the 4.2 million E-rated homes face bills that are £320 a year higher than those in C-rated homes, according to the think tank.
People living in the 1.5 million F-G rated homes will face a surcharge of £390 by comparison, it found.
Brits are already facing a cost of living crunch as rising prices are compounded by the hike to National Insurance contributions in April.
The figures emerged as part of an analysis of the impact of the Government's net zero plans on household consumption.
The Resolution Foundation said the biggest areas of decarbonisation will come via residential buildings (to fall by 44% by 2035) and transport (a 64% reduction by 2035).
Most of the focus has been on slashing emissions using technology such as heat pumps and electric cars - but work needs to be done on the infrastructure to make this work, such as charging points and home insulation.
Jonny Marshall, Senior Economist at the Resolution Foundation, said the impact of the transition to net zero would begin to bite for households over the next decade.
He said: “Much of the focus has been on take-up of low-carbon technologies like electric vehicles and heat pumps.
"But the key to their success will ultimately depend on delivering the infrastructure around them – such as better insulating Britain’s housing stock.
“This long-term insulation challenge will be brought home to households very soon when energy bills rise by 50 per cent in April.
"Almost six million households will face a £320 ‘leaky homes surcharge’ on their energy usage as a result."
Ministers want to better insulate private rented accommodation by ordering properties to attain a C-rating by 2028.
But there is no plan for the two-thirds of households who own their homes.
The report found 72% of low-income homeowners need insulation upgrades, which carry a price tag of up to £8,600.
It comes as figures from poverty charity Turn2us showed that more than half of callers (52%) to its helpline over the past year needed urgent support to pay their bills.
A Government spokesperson said: "Improving the energy efficiency of our homes is the best long-term method to keep household energy costs down and to tackle fuel poverty.
“That is why we are upgrading the energy efficiency of England’s homes by investing over £6.6bn billion to decarbonise homes and buildings and bringing in higher minimum performance standards to ensure all homes meet EPC Band C by 2035.”
