There are four basic types of lighting: the traditional incandescent bulb, halogen, fluorescent and most recently LED lighting.
The traditional incandescent bulbs work by using electricity to heat a tungsten filament to very high temperatures so that it glows. Really therefore, they are mini heaters which produce light as a by product and this, together with the limited life span (because the element will inevitably burn out) is what makes them so inefficient. Fluorescent lights pass electricity through mercury vapour causing it to glow (or fluoresce). Although more efficient than incandescent bulbs, the use of vapour to convert electricity to light causes wastage.
Energy-saving light bulbs use up to 80% less electricity than the old bulbs but produce the same amount of light. And they last around 10 times longer. Since 2011, all bulbs manufactured in or imported into the EU are required to meet new energy efficiency standards. Since they use just a fraction of the electricity that their predecessors use, the new bulbs can save an average household around £3.00 per light bulb, per year. Like the old-style bulbs, energy-saving ones come in all shapes and sizes. You can buy them for bayonet or screw fittings. They are often shaped like traditional light bulbs so they don’t stick out of your lampshade. Even dimmable low-energy bulbs have now been developed.
What’s more, the most recent models have a softer and warmer light, very similar to the old-fashioned bulbs that they are replacing. And while they still take a short while to warm up to full brightness, the decent brands are improving in this respect. Look out for bulbs carrying the Energy Saving Trust ‘recommended’ label, as they reach a target brightness very quickly.
If a bulb carries the blue ‘Recommended’ logo it will produce light of a similar warmth to a traditional bulb, get bright quickly and last for at least 6,000 hours.
Because they use less electricity, energy-saving bulbs have lower wattages than traditional bulbs. This means you can replace a old-style 100W bulb with a 25W one, and it’ll give the same light while using a quarter of the electricity (see table below). In fact, because the useful measure of a bulb is actually how bright it is, they will soon be sold by lumens which measure light, rather than watts, which measure electricity. The more lumens, the brighter the bulb.
Comparing watts and lumens
|Traditional bulb||Energy saving bulb||Equivalent in Lumens|
LEDs (Light Emitting Diodes) have been around for decades and are used as stand-by lights on TVs, DVD players etc. They work in a similar way to fluorescent lights but with no gas which greatly reduces wasted electricity. Although very efficient in terms of electricity consumption, the problem has always been how to harness the technology to produce a useful light source. The solution, it turns out, is to group a number of diodes together.
LED Lights are around 5 times as efficient as an incandescent bulb. To put some perspective on this, an “average UK electricity bill is around £500 per annum, of which around 20% is made up of lighting costs. If LED lighting is 5 times as efficient as incandescent then replacing all bulbs with LED lighting would reduce the annual lighting bill from £100 to around £20. In addition, a LED light will only have to be replaced on average every 15 – 20 years. In that time around 40 – 50 incandescent bulbs would need to be purchased. So the major advantages of LED lighting are cost efficiency and longevity. These are also environmental advantages of course.
Advantages of LED Lights
- LED lighting produces no UV light (which can cause health problems)
- They contains no mercury (which is damaging to the environment)
- They light up instantly unlike other low energy lighting
- They are very robust compared to incandescent bulbs and fluorescent tubes, which are notoriously easy to break.
Disadvantages of LED Lights
- Initial high cost
- Directional nature
Typical LED Costs and Savings
A 5 watt LED bulb, with equivalent output of a 60 watt incandescent bulb (a typical ceiling light/lamp bulb) will cost around £15, so to replace all of the bulbs in a typical home which will have around 12 bulbs would cost £180. Although this seems awful lot to spend on light bulbs, if you remember that during the lifespan of an LED bulb you would need to buy up to 50 incandescent bulbs, so unless you could get each one for 30p or less, LED bulbs will eventually work out cheaper, even without the efficiency savings. With efficiency savings of around £80 per year however LED lighting will in fact pay for itself in just over two years and will continue to shine for many more years to come.
Unfortunately there is no funding available for lighting in the domestic sector. However, we recommend that you replace your standard bulbs with energy efficient ones such as these, as it is one of the cheapest and best investments that you can make.