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Light qualities of energy-saving bulbs


Most people are used to choosing a bulb by a certain number of watts - for example, 40W. But the wattage is really a measure of the power consumption of the bulb, so it's not a good measure of light brightness. Lumens (lm) is the measure of light output, and this is the one to use when choosing a bulb.

Many manufacturers give a 'watts equivalent' figure on their packaging to indicate the brightness level. However, since September 2012 brightness should be advertised in lumens.


Different bulbs give different colour light. Old-fashioned, incandescent bulbs give a quite yellow light, and most people are used to this. When the first compact fluorescent lamp (CFL) bulbs came out, they gave a more blue-white light, which many people found unpleasant. It's possible that you have some of these bulbs at home, or that you got some when they came out and have gone back to traditional bulbs.

New CFL bulbs have been designed to give light in the same colour as old-fashioned bulbs, so they should be much more acceptable. Halogen bulbs give very similar light to old-fashioned bulbs. LED bulbs can give light in just about any colour.

Check the packaging and look for the colour light you prefer. Some people need light in very specific colours to see clearly. You may need to take some advice from a sight-loss specialist, such as an ophthalmologist or orthoptist.


All bulbs will cause glare if you can see the bulb directly. If this is a problem for you, make sure you have a good shade. If a long, stick-shaped CFL bulb pokes out of the top or bottom of a shade, get a shorter bulb or a taller shade. Thomas Pocklington Trust has information on this.

Last updated: June 2014

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