Tag Archives: energy efficient

What low Watts? – Wattage Comparisons

shock that LED peer consumption is so lowIt is poignant to reflect on the low adoption of LED currently. Figures of a mere 7% have been published which seem to poorly serve the huge benefits offered by the technology. Certainly these results do not match my everyday experience of a growing client base of new converts. However there are those who resist change – no more so than ‘end user’ clients themselves; many of whom seem to wish to cling on to the familiar. Ask any high street electrical store and they will show you their ‘under the counter’ stock of incandescent bulbs!

So what is the reason behind this resistance? Well the answer is blinking obvious! People need a reference point to transfer from the familiar to the unfamiliar – yet manufacturers and promoters of LED have been slow to provide this guidance.

Historically we have always looked at the wattage of a lamp; the amount of power it requires to assess it’s size – and output.

GLS lamps all have a filament that is heated, requiring more energy to make them burn brighter. However this makes no comparative sense when selecting LED. By its very nature LED requires a much lower wattage to function. The practice of using wattage to measure LED output has to stop – it is effectively a barrier to understanding.

Time to change
LED light sources are much more efficient at converting watts to lumens. Different materials can be used within the LED sources themselves, each of which has its own light extraction efficacy. For these and other reasons, two different LED sources can consume the same number of watts but differ widely in lumen output.

Lumen output – the amount of light that is leaving the fitting is the only sensible metric.Megman-for-web-shotFor instance on lighting packaging you often see 1 x 3W LED specified on a fitting in a catalogue – where is the lumens figure to guide us? Additionally, how can I tell how many of those lumens are going to fall where I need them? Hence we cannot rely solely on wattage, as other factors play a part including the lens and the driver.What do we do?
In terms of explanation, I convert client understanding to lumens by stating that the lumen level of a 60 watt incandescent bulb is roughly 700 lumens – then we can happily benchmark our comparison with LED in terms that everyone can understand! Using charts like the one above are invaluable.

Footnote: The lumen output is our best guide – but if we are really getting to grips with this topic then lumens only is not an accurate measurement across all fittings – but we’ll cover that another time.

Whatever the confusion caused by LED – planning, specifying or installing – call us and we will be able to guide you through the alternatives that fit your requirements.