What is a watt?
A watt is a measure of power consumption.
The wattage of a bulb actually tells you how much electricity it uses, not how
much lights it produces. Traditionally lamps have always used watts as an
indication of the lights that can be expected from the bulb. However, with new
technology and more efficient lamps, watts are becoming increasingly irrelevant
and eventually all lamps will be measured in Lumens.
What is a Lumen?
Lumens are a measure of light. Typically
one lumen is equivalent to the light emanating from a single wax candle. A
conventional 40 watt light bulb would have a lumen output of around 450lm. A
CFL with the same lumen output would only use approximately 9 watts and an LED
considerably less depending on the type. As a general guide the efficiency of
an incandescent lamp is 10-12lum/w, a CFL is around 50 - 60lum/w and an LED can
vary from 40 - 110 lum/w. Remember: the higher the lumens the brighter the
What does voltage mean?
Voltage is the pressure within the circuit that's generated by the electricity company from the national grid. Different
countries use different voltages according to their infrastructure system, its
generally referred to as the electrical potential.
In the UK the current used is typically 240
volts, in America 120 volts and in most if Europe and the Far East the current is typically 220 volts.
In general different plug sockets are used
to ensure people use the correct equipment relevant to their local current.
A good analogy is to imagine the pressure
behind the flow of electrons in a circuit similar to water pressure in a
What does colour temperature mean?
Correlated Color Temperature(also known as
CCT) describes the appearance of the light in degrees Kelvin. It is the measure
of the colour of light emitted; it can be quite yellow (2700k) or very blue
white (6500k). In the UK most home lamps are 2700k to 3500k.
Did you know? Some workshop prefer to use
lamps with high colour temperatures. As 6000K gives more lumens than 2700K and
give off a very white colour.
What does CRI mean?
CRI, or colour rendering index, measures
the light quality of a light source as compared with sunlight (which is given
the maximum CRI value of 100). The closer a light - sources CRI is to 100. The
better its ability to show true colours. Lamps with a CRI of 85 - 90 are suited
for venues such as art galleries, retail shops and photography where showing a
good colour rendition is critical. Lamps intended for domestic use are able to
have a lower CRI level (as low as 60). Which allows manufactures to produce
products at lower price points whilst also providing suitable light. Remember:
for the home, a higher CRI is not critical providing the optimum light level.