Britain proposed to allow all households from 2012 to apply for loans and cash to save energy and cut carbon emissions, costs energy companies are likely to meet and pass on to all consumers.

Green groups welcomed the plans but criticised a perceived lack of clarity and timidity in timing and funding.

"We need to move from incremental steps forward on household energy efficiency to a comprehensive national plan," said Energy and Climate Change minister Ed Miliband.

"Energy efficiency and low-carbon energy are the fairest routes to curbing emissions, saving money for families, improving our energy security and insulating us from volatile fossil fuel prices," he told reporters and trade and policy experts.

One proposal under the plans, open for consultation, would allow any household to get a loan to pay for insulation or to install renewable sources of heating, and repay that from the resulting energy savings.

The government did not detail how much the scheme would cost, nor exactly who would provide the loans - which could be energy companies or the public sector.

Under the plans households would also get from 2011 regular cash payments in return for producing heat from fossil fuel alternatives including the sun or waste dumps, a novel idea developed from payments for renewable electricity which many European countries already provide.

Energy companies could also make those cash payments.

The aim was for all UK homes to make near-zero carbon emissions by 2050, the energy and climate ministry said in a statement announcing its Heat and Energy Saving strategy.