US Edition 
How to save '£240 a year' with LED lightbulbs
LED bulbs use a fraction of the energy of traditional bulbs but cost a lot more to buy. We do the sums
The savviest buy you make this year could be a box of new light bulbs. An investment in the latest expensive but super-efficient bulbs could save you £240 a year and pay for itself within five months.
These bulbs, which are made up of LEDs (light-emitting diodes), are about 10 times more efficient at converting electricity into light than the old-fashioned filament variety. This explains the difference in the wattage needed.
So, to replace a traditional 60W bulb you need just a 6W LED bulb.
Although they are considerably more expensive to buy than traditional light bulbs and other “low energy” types of bulb, such as those that work more like fluorescent lights, they consume so much less electricity that you will quickly recoup your outlay in lower bills.
We asked the online switching service Comparethemarket.com to calculate the numbers in detail. For simplicity’s sake we’ve looked at a medium-size home containing 10 light fittings, each currently with an old-style 60W bulb. We’ve assumed that the owners are retired so the lights are on for an average of 10 hours a day.
The total power consumption of the 10 lights with old-style bulbs comes to 600W or 0.6kW. Electricity is sold in units of kilowatt-hours (kWh) – the amount of energy that a 1kW device uses in an hour. So each hour the 10 lights consume 0.6kWh. Based on a typical unit price of 12.2p per kWh, the 10 lights will cost 7.3p per hour to run. The daily cost is therefore 73p if on for 10 hours. This is equivalent to £5.11 a week, £21.90 a month or £266.45 a year.
If you replace all the bulbs with a 6W LED equivalent, the running costs will be just one tenth – or 7.3p per day, 51p a week, £2.19 a month and £26.65 a year.
The savings are therefore 65.7p a day, £4.60 a week, £19.70 a month or £239.80 a year.
What would 10 of these 6W LED bulbs cost you? We found them for £8.99 each online, although their cost is likely to fall as they become more popular. Replacing all 10 would therefore cost £89.90, which would take less than five months to recoup. In the first year your net saving would be £149.90.
Better still, LED bulbs last a long time. Or, at least, they are supposed to.
Under a soon-to-be-implemented EU rule, they should have a minimum lifespan of 6,000 hours – which, at 10 hours a day, would mean your bulbs should last at least 18 months. But Which?, the consumer magazine, said some fell short of this standard in its recent tests.
However, some manufacturers say their LED bulbs should last 40,000 hours and not blow until you have switched them on and off 100,000 times.
You’d need a 12W conventional “low energy” bulb to provide the same amount of light as a traditional 60W bulb, so the saving here is a still substantial £213 a year, or £168 after the £45 typical cost of 10 bulbs.
LED bulbs are available in all shapes and sizes, and produce a variety of shades of light, such as “daylight” and “warm white”.
So you can use them to replace traditional bulbs of the bayonet and screw-in types, as well as the more modern mini-bayonet sockets used for small halogen spotlights and inset ceiling lights or downlights.
They come on instantly; there is none of the slight delay or flickering that you sometimes get with older-style low-energy bulbs of the “compact fluorescent” type.
They also generate little or no heat, making them safer alternatives to hotter bulbs.
The savings from LED or other low-energy bulbs will be even greater if you are on a more expensive tariff. For example, “Economy 7” deals can be very expensive for daytime consumption because they are geared to people who use more electricity at night to power storage heaters. The most expensive Economy 7 tariffs cost as much as 18p per kWh. In the household described above, annual savings would be £345, Comparethemarket said.
Of course, fitting efficient light bulbs is no reason to avoid shopping around for a better electricity deal using a comparison service. Some, such as Comparethemarket and energyhelpline, can help you find the best deal over the phone as well as online.
James Padmore of Comparethemarket said: “Most people are aware that by making your home more energy efficient, great savings can be achieved.
“But people might not know just how easy being more efficient can be – by simply changing your light bulbs. Such small changes to the home can have a positive impact on people’s finances; a first-year saving of £149 would pay for a year’s TV licence, for example.”
We include more energy-saving ideas in our weekly newsletter.
• Have you already made the switch from traditional bulbs to LED? What do you think? Email us at money@telegraph.co.uk or comment below.
• Put a household energy question to our experts at moneyexpert@telegraph.co.uk