We sort out our plastics, stockpile old newspapers and rinse out tin cans for recycling - but is it making a blind bit of difference? Environmental expert Joanna Yarrow reports

Most of us are confused about going green, nervous about having to convert our homes into environmentally sound palaces - and terrified of the financial penalties being threatened if we don't.

And politicians fighting to be the greenest of them all as they promise myriad taxes to price us out of the skies are enough to make the average citizen rush out and book the longest-haul flight, or swap their petrol-electric Toyota Prius for a huge gas guzzler. It's all a bit daunting. But don't despair. Here are the 15 easiest ways to reduce your carbon footprint.

1 Stop drinking bottled water We are lucky to have high-quality water coming from our taps for next to nothing in Britain. Why not drink it? We use 2.7 million tonnes of plastic to bottle water each year. Only about 10 per cent of bottles are recycled; most go to landfill sites, where they take around 450 years to break down. One litre of water weighs a kilo. Imagine how much fuel is used carrying it from its source in the Alps or the Highlands.

Buy filters to reduce the chlorine content if you don't like the taste, but some experts insist that tap water is of better quality (with higher mineral content and lower risk of contamination) than bottled.

2 Don't use carrier bags In Britain, we use around 8 billion plastic bags every year. That's more than 130 plastic bags each annually, and for most of us they are an irritation. How many cupboards under the sink are stuffed with them? Re-use your bags or, better still, get hold of a re-usable one that's cheap and sturdy.

3 Watch your water use The average bath uses 80 litres of water, twice as much as the average shower. If you normally clean your teeth for three minutes, turning the tap off while you brush will save almost 19 litres of water - that's more than someone in Kenya uses in a whole day. Ask your water company for a free "hippo" - a simple plastic device to put in the cistern to reduce the amount of water used in each flush. Flushing the lavatory accounts for around a third of all domestic water use.

4 Install a condensing boiler to heat your water and home, and cut your energy bills by at least 25 per cent. If everyone in Britain with gas central heating installed a condensing boiler, we would cut CO2 emissions by 17.5 million tonnes and save £1.3 billion on our energy bills every year. This is enough energy to supply more than 4 million homes for a year. A new boiler is a large investment (£1,500 plus), but at least you get a return for your outlay.

5 Use energy-saving light bulbs They don't have to be those loop-shaped ones that cast an ugly yellow hue. They come in all shapes and sizes now (see ebulbshop.com) and usually last at least 10 times longer than standard bulbs, using a fifth of the energy. You could save around £100 a year if you switched. If everyone in Britain replaced just one 100W light bulb with a 20W energy-saving one, we'd save the same amount of energy as that produced by Sizewell B nuclear power station.

6 Don't overfill your kettle If just 15 families filled only to the level needed they would save 1 tonne of CO2 emissions every year.

7 Lower your thermostat by 1 degree C It will cut your annual fuel bills by a 10th and save 240kg of carbon over a year.

8 Buy organic food Organic food production causes much less environmental damage than conventional agriculture. Make sure the food is locally produced. Half of all vegetables and 95 per cent of fruits eaten in Britain are from overseas, and the average meal travels more than 1,000 miles before it reaches your plate.

If you buy from farmers' markets, you will have the satisfaction of buying directly from the producer, there's no plastic packaging and your vegetables will last longer than the supermarket ones. Even if you shop like this only some of the time, it will have a big impact over your lifetime. Bigbarn.co.uk will tell you where to find your nearest farmers' market or producer.

9 Reset your computer Switch your screensaver setting to "none" or "blank screen" and set your computer to enter power-saving mode after 10 minutes of inactivity. Leaving your computer on overnight can waste enough energy to laser print 800 A4 pages. That adds up to 2,600 kilowatt-hours of energy each year, producing up to 1.9 tonnes of CO2, without doing any work.

10 Save paper Each office worker in Britain generates an average of 50 sheets of paper per day. If you use both sides of the paper, this will decrease your greenhouse gas emissions by 2.5 kilograms for every kilogram of paper used.

11 Don't buy "sweaty" fabrics such as nylon and polyester They're made from petrochemicals in a process that uses large amounts of energy, water and synthetic lubricants. The nitrous oxide released during the manufacture of nylon is 310 times more potent than CO2 as a greenhouse gas. Opt for natural fabrics whenever possible.

12 Use your washing line Tumble dryers use more energy than any other household appliance, so use them only as a last resort. Cut your tumble dryer use by one load a week and you will reduce your CO2 emissions by 91kg a year.

13 Wash at lower temperatures What is it with the British and the hot wash? In Japan, Europe and even America, clothes are typically washed below 30 degrees. Washing at a lower temperature - especially as the average British family does 247 loads a year - is an easy way to save a lot of energy. If everyone did it, we'd have enough spare energy to power half a million homes.

14 Convert to a green energy tariff Supplying your home with electricity produced from renewable sources will cut your household CO2 emissions by up to a third, and takes a single phone call. Good Energy and Ecotricity both provide 100 per cent renewable tariffs, which may be marginally more expensive than typical providers - but as this will be an incentive to use less energy, your bills may end up lower. See www.uswitch.com/energy for details on the full range of green tariffs.

15 Recycle! This may sound obvious, but it is not just paper and plastic bottles that can be recycled - about 80 per cent of our waste is recyclable. Visit www.wastepoint.co.uk for what to do with the stuff that you can't put in your doorstep box or bags from the council.

'1001 Ways You Can Save the Planet' by Joanna Yarrow (Duncan Baird) is available for £7.99 plus 99p p&p. To order, call Telegraph Books on 0870 428 4112.