Residential housing is currently the third-largest contributor to CO2 emissions, according to data collected by the firm.

“As two-thirds of the UK’s housing stock falls below the C grade on Energy Performance Certificates (EPCs), we need to focus on making our existing stock more efficient,” according to Claire Singleton, chief executive of Legal & General Home Finance.

Singleton went on to explain that a “few improvements can make a massive difference to the environment, the bills we pay and a property’s market value.”

Installing an air source heat pump could cut a home’s CO2 emissions by 2,600kg per year, saving close to £700 in the process, the data shows.

Singleton added: “Even basic changes, such as double glazing and draught proofing, can save hundreds of pounds a year.

“We want to support our customers who are taking action to reduce their emissions and leave a positive legacy for future generations.”