When is a Specification Really a Specification?


Apples and Oranges

The introduction of LED lighting, and its fast evolution, has increased the number of variables within specifications. So, how does the buyer compare such a vast range of options?

Before LED, light output or “brightness” was often correlated to the power of the fitting. Brightness was thought about in terms of wattage – most of us can remember the 60W or 100W incandescent light bulb. This type of thinking has been passed on to LED luminaires.

However, this can lead to confusion, because the light output (lumens per watt) of the LEDs used can vary greatly. For example, a 36W panel using 80 lumens per watt LEDs will produce 2,880 lumens. Compare this to a 30W panel using 130 lumens per watt LEDs which will produce 3,900 lumens: 17% less power producing 35% more lumen output.

But simply focusing on light output, rather than power consumption, isn’t always enough. Some manufacturers publish the light output from the LEDs. Others publish the light output from the entire luminaire, which will usually be lower, as the light from the LEDs is diffused within the luminaire.

This relationship between power and light output is just one example of where confusion creeps in and buyers end up trying to compare apples with oranges.

Price vs. Specification

Price is usually also a major factor in choosing the appropriate luminaire, but manufacturers can manipulate price points according to the specifications. For example, having decided on a 36W panel light with 80lm/W LEDs, does the panel have a flicker free driver? Does it have a TP(a) or TP(b) flammability rated diffuser to meet building regulations? Does it have a Unified Glare Rating (UGR) less than 19? What is the colour rendering index of the light? These are all variables within specifications which can make a big difference to the quality of the light and the price of the luminaire.

Need for Consistency

It is not surprising that many buyers are confused. There is clearly the need for consistency across the lighting industry for publishing product specifications, so that better comparisons can be made.

In a recent Guidance Paper on Evaluating performance of LED based luminaires by LightingEurope, they are “… of the opinion that the establishment of simplified performance metrics that support the needs of good lighting design and allow easy product to product comparisons to be made will add value to the professional market.”

Without consistency in specifications, buyers may be comparing apples with oranges and accidentally end up with a banana!

Removing Confusion

Many reputable lighting suppliers, such as NET LED Lighting, are working closely with organisations such as the Lighting Industry Association to promote best practice throughout the sector.

To help to remove the confusion faced by buyers, NET LED supports its customers’ businesses from enquiry to order. Throughout the buying process, the Sales and Technical Teams help to establish the optimum solution in terms of light quality, cost effectiveness and the lighting specifications required. NET LED can provide lighting designs, energy savings calculations and sample products for each project. To discuss the lighting specifications of your project, get in touch with NET LED on 01223 85105 or email We may prevent you from accidentally ending up with a banana!