With gas now on the nose, householders are switching to more energy-efficient – and green – power. Where do you start?

"Not everyone can afford these things because they require some upfront investment,” he says.

What should you do first? They are much more efficient than old-style electric and gas water heaters and can cost very little to run when drawing power during the day from a home’s solar panels, which Jolley and Besley installed next, aided by a government interest-free loan (more on that later).