Lighting Terminology
WATTAGE:
The wattage of a light globe or fitting tells you how much energy it uses. LED lights use less energy to produce the same amount of light as incandescent globes. This is why an 8W LED globe will be approximately as bright as a 60W incandescent globe, even though it draws significantly less power.
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LUMENS:
Lumens are a unit of measurement of the amount of light produced by a globe or light fitting. Looking at the lumen output of a globe will give you a better indication of how bright it will be than looking at the wattage.
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The following chart gives a rough comparison of the lumen output of different wattage incandescent, halogen, compact fluorescent and LED globes. Keep in mind that the lumen output will be affected by the type of glass or plastic covering the light source, for example if it's clear or frosted.
KELVINS:
The colour temperature of a light bulb is measured in kelvins, with a range of approximately 1700K - 8000K. The lower the kelvins, the warmer the colour of the light will be. The higher the kelvins, the cooler the light colour.
CRI:
CRI stands for Colour Rendering Index and it is a measurement of how well a light source accurately shows the colours of the object it is illuminating. It is measured on a scale from 0 to 100. The closer the CRI is to 100 the truer the colours will appear. A CRI of 80 or above is considered good.
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IP RATINGS:
Ingress Protection (IP) ratings refer to how protected an electrical item, such as a light fitting, is against solid particles and liquids. The rating is displayed as the letters IP followed by two numbers. The first number indicates the level of protection against solid particles, such as dust. The second number indicates the level of protection against water.