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Light up your world

woman holding energy bulb 01 3 12As well as being a vital design feature in your home, you need to make sure the lighting you choose is kind to the environment as well. We give the low-down on the latest developments.

You wouldn’t think that humble lighting could cause damage, but it is one of the biggest contributors to global warming, making up approximately 20% of the world’s carbon emissions. So if you are considering renovating your house, then you need to give the lighting serious consideration and make sure it is not only sympathetic to your décor but also to the environment. Even just changing the type of light bulbs you use can make a big difference to your carbon footprint.
 
Low-energy option
You don’t have to make massive changes – most homes today use a variety of standard light fittings and halogen downlighters or spotlights, which you’d find mainly in kitchens and bathrooms. Next time one blows, replace it with a low-energy alternative.
 
Out with the old…
Traditional light bulbs, known as tungsten filament or GLS (General Lighting Service) bulbs, are extremely inefficient. Only about 5% of the electricity they use is converted into visible light. The filament is heated up until it glows, giving off a yellowish white light. The lamps do not last long because the filament gradually evaporates. The much more efficient alternative is compact fluorescent lights (CFLs) – these are what most people think of as energy efficient. They are powered by a gas inside a glass tube that is charged up so it glows. This causes a coating on the inside of the glass tube to give off the white light. CFLs use about 20% to 25% of the electricity that an equivalent GLS lamp will use. And CFLs have vastly improved since they first became available. Originally they cast a stark light, but now they come in all shapes and sizes and with different colours of light – from the warm yellowish traditional glow to a cooler, pure white for optimum visibility.  Modern CFLs do not flicker and they can reach full light output quite quickly, though not instantly.
 
Long-lasting LEDs
LEDs (light-emitting diodes) were first around in the 1960s in alarm clocks, calculators and display panels in electronic equipment. They have since been adapted for many uses, including traffic lights, brake lights and pool illumination. They work by using light-emitting diodes. A diode is a simple solid state electronic device that allows electricity to flow in one direction only. A light-emitting diode, as the name suggests, gives out light as the electricity flows through it. The downside is they only emit a small amount of light. It has taken a long time to develop a lamp that can fit enough LEDs together into a small space to be an effective replacement for domestic lighting. LEDs are the ideal replacement for halogen downlighters and these are now available from specialist suppliers and some retail chains. They do seem expensive compared to other options, but they are the most efficient option of all because they last far longer than any other technology, and they will pay for themselves several times over before they need replacing. Some lamps and luminaires do cost you more to buy but last an incredible 50,000 hours and use very little energy, which has to be worth the purchase.

Halogen lamps
These use a very similar technology to GLS lamps, but run at a much higher temperature, making them more energy efficient. Most people use halogens in spotlight downlighters. They are more efficient than old-fashioned GLS bulbs, but because you have to use a high number, the total amount of electricity used to light a room is often higher than other options. Many rooms with halogen downlighters are brighter than they need to be so you may be able to save money by installing lower output bulbs. The ideal energy efficiency alternative to a halogen downlighter is an LED.
 
Simple savings
Changing your lampshade can save electricity because a dark colour shade can easily absorb more than half the light output of a bulb before it has the chance to light up your room. A transparent shade or fitting will allow more light to go into the room. Some fittings, especially spotlight ones, have a reflective inside to direct as much of the light as possible in the required direction. This can increase efficiency if light is needed in one place. Halogen spotlights have the reflective surface as part of the bulb, and LEDs give out directional light anyway, so they don’t need a reflector. Some fittings have a glass or other transparent covering to hide the bulb without losing much light output. You need to keep these clean so the light can filter through effectively. Some light fittings are designed only to take CFLs – you couldn’t fit an inefficient GLS into them even if you wanted to. The fitting contains the ballast (electronic circuitry) that most CFLs have in the bulb itself. So when the tube eventually fails you only have to replace the tube, not the whole lot. Unfortunately, the tube-only CFLs that you need for these fittings are much more expensive than standard CFLs, so you save less money with this type of fitting. And with GLS bulbs being phased out, there’s no real benefit in having a CFL-only fitting. So think carefully about the kind of lighting for your needs.


This article was first published in at home with Sarah Beeny in December 2011. [Read the digital edition here]


Photograph: Getty Images

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