Leave it off: that’s the message on “E-day” - energy saving day - which runs for 24 hours from 6pm on Wednesday 27 February. Everyone who wants to take part is being asked to switch off non-essential household electrical items - lights in empty rooms or overnight, mobile phone chargers, and computers, printers and televisions when they aren’t in use.

The cumulative effects of millions of small energy saving measures will be shown minute-by-minute on the E-day Web site. Given the number of non-essential household items left on or on standby, widespread uptake of the call to action has the potential to result in a 1 to 3 percent drop in Britain’s electricity usage. Repeated regularly, it would equate to permanently turning off a medium-sized coal-fired power station or some 500 wind turbines. In fact, if every household in the UK turned off just one 100 watt light bulb each during E-day, four medium-sized coal-fired power stations could cease to exist.

By showing the cumulative effects of millions of peoples’ energy saving efforts, the campaign hopes to motivate the public to make the little changes that can lead to big reductions in greenhouse gas emissions.

As an added bonus of helping to tackle climate change, there are attractive cost savings to be made. Five simple steps can cut your energy use by 10 percent - and your energy bill - according to price comparison service energyhelpline.com:

1. Close your curtains at dusk. This could save you about 15 pounds per year and reduces yearly C02 emissions by 50 kilograms.

2. Unplug your phone charger when it’s not in use, and you will pocket an annual saving of 10 pounds and take 33 kilograms of carbon emissions off of your annual CO2 total.

3. Turning your thermostat down by just 1 degree Celsius will reduce your heating bills by 10 percent - typically 45 pounds per year.

4. Use low energy bulbs. These use a quarter of the electricity of ordinary light bulbs and last ten times longer, and could net a typical saving of 40 pounds per year.

5. Consider switching to a green energy tariff. This could save you up to 150 pounds per year and drastically reduces your C02 footprint — a typical two tonnes per year.

This saving, it has to be said, applies generally to those who have never switched utility provider - and traditional tarrifs that focus less on green energy sources tend to be cheaper. For the eco-minded, of course, no price can be put on saving the planet.