Greenbang knows Londoners are lazy. As a capital dweller, she doesn’t like to think about the amount of episodes of Keeping Up Appearances or Last of the Summer Wine she’s watched because the TV remote control was 1cm out of arm’s reach.

But good news for all of us living inside the M25 – without making much effort or coming up with some crazy new space age clean tech, we can save 44 millions tonnes of carbon and not even have to raid our piggybanks that much.

That’s the findings of a new report from consultants McKinsey, commissioned by Siemens. Using all the tech we have to hand, we could still cut 44 percent of our carbon emissions by 2025.

And better yet, 70 percent of the technologies we’d use would pay for themselves.

For the sceptical London residents out there thinking ‘when you say, without making much effort – how little effort are you talking?’

This little effort in fact:

Energy-efficient lighting in London households is the single most
cost-efficient measure and would cut CO2 emissions by 400,000 metric tonnes, saving €270 per tonne abated. The greatest reduction – a total of 4.5 Mt – could be achieved through improved insulation.

• Green certified homes sell faster, higher price