The first step on the way to making a home carbon neutral is to fit energy saving light bulbs. They use about 25% of the electricity of tungsten filament ordinary bulbs and generally last eight times longer than ordinary bulbs. If we all made just this small change to our lighting needs it would have a big impact on the UK's emissions. A recent study found that if every household in the US replaced just three ordinary light bulbs with energy-saving bulbs and used them for five hours a day, it would reduce carbon dioxide emissions by 23 million tonnes.