Its new report suggests low income households with pre-payment energy meters are suffering twice as much fuel poverty.
Where some households have the opportunity to shop for good deals, the Poor Pay More report suggests others are forced to pay hundreds of pounds extra by using the pre-pay meters.
Before seeking help from CAP, among debt clients with pre-payment meters:
- Two thirds (67%) couldn't heat their homes
- A third (33%) couldn't cook their food
- Almost a quarter (23%) couldn't wash their clothes
- One in ten (11%) couldn't afford to wash themselves
Speaking about the findings, CAP's Chief Executive Matt Barlow said: "Across the board, we consistently find a direct correlation between desperate situations and those on pre-payment meters.
"Having looked at these results, we do not think that it is either just or fair that those with lower socio-economic means face greater charges for their energy.
"CAP is recommending something simple - the poor should not have to pay more. "We are asking that everyone should pay the same, regardless of payment method.
"We don't think that lone parents; those with mental health problems and those with physical disabilities should be penalised by paying more for their fuel."
CAP surveyed more than 1,700 debt clients and found that 42 per cent were on pre-payment meters. Research showed that on average each year these clients paid an extra £140 for gas and £90 for electricity creating an intensification of the hardship from debt problems.
Those with meters were 22 per cent more likely to sacrifice meals before they sought help from the charity. Seven in ten with meters were found to be vulnerable.
Across the country, 3.7m households are known to have an electricity pre-payment meter and 2.5m households have a gas pre-payment meter.
Hear CAP's Rachel Gregory speaking to Premier's Marcus Jones on the News Hour: