Light Output – lumens
This information is with regard to LED lighting, other types of lighting are measured in a different way making it hard to make direct comparisons. We are happy to advise on this.
Light output is measured in lumens and generally speaking with LED lighting is equivalent to the useful amount of light produced.
Input Power – Watts
Input power can either be specified as the power consumed by the LEDs in the light fitting or a total input power as provided to the driver. This is the more useful figure as it will determine the power consumption of the light fitting.
Efficacy – lumens per Watt
Efficacy is a measure of how efficiently the light fitting converts electricity to light output and is measured in lumens per Watt. The efficacy is calculated by dividing the light output by the power consumed. When the power consumed by the driver is used this is known as circuit efficacy. A higher figure is better as this means that more light is produced for a given amount of power consumed.