The bank's new Breathe Easy card and loan product is expected to be launched next summer.

Barclays says customers using the Breathe Easy card to buy home-efficiency products from selected retail partners would receive an initial discount on the purchase. They would then repay the cost of the purchase as a loan where their monthly repayments are expected to be in line with the savings they would make on their energy costs.

After the loan period, the customer will make savings for as long as they live in the house, says the bank.

Barclays chairman, Marcus Agius, says many homeowners are put off investing in greater home energy efficiency by the cost of doing so and the time it takes for their investment to pay them back in terms of lower energy bills.

"Barclaycard Breathe Easy addresses this challenge and is a good example of the role which financial institutions can play in helping consumers reduce household carbon emissions," says Agius.

Earlier this month the bank released its new 'carbon-offset' corporate charge card for business customers to offset emissions created by business air travel. The Barclaycard Business Sustain card follows the launch in April this year of Barclays' Breathe credit card which offers customers incentives - including discounts on home insulation, green energy and holidays in the UK - to encourage greener spending. The bank also donates 50% of Breathe profits to environmental projects dedicated to reducing carbon emissions around the world.

Other banks have also jumped on the "green" bandwagon. In October the UK's Co-operative Bank launched a new green credit card that offers a lower rate of interest on purchases made from selected ethical partners, while last year Dutch banking group Rabobank launched its 'climate credit card' which contributes funds to environmentally-friendly projects every time the card is used to pay for energy-consuming goods and services.