How to choose a good LED

The market is flooded with various quality LED lights, all of which are labelled ‘the best ones out there’. Unfortunately, many of these LEDs don’t last the expected lifespan and therefore don’t produce the savings. The question of how to ensure your LEDs save the promised 70% compared to fluorescent lights, and last up to 50,00 hours is increasingly important.

There are a few important measures that need to be considered when choosing an LED light. The five main measures, along with our suggested tips, are:

1. Efficiency & Efficacy

Both, often confused, are important in knowing what will be your savings from installing LEDs.  Efficiency is the percentage of how well a light turns watts into lumens*, whereas an LED’s efficacy is rated by how many lumens are produced from each watt of energy. In most cases it is the efficacy that is rated in LED specifications. Commonly it is around 30-60 lumens per watt, however, the improved technology in our LED lights allows to increase the efficacy up to 85-100 lumens per watt.

Top tip = Know the difference between lumens per watt VS lumens per circuit watt

*lumen – total measure of light

2. Lumen depreciation

Like any other lights, with time LEDs lose their ability to produce light - the light level drops over time and could render the LED not fit for use. The human eye will not notice a decrease of -30%, but by how much does an LED's output drop and over what length of time? This impacts the rated life of an LED (check tip no. 5).

Top tip = If you’re buying a commercial light ask for an LM-80* test report  

*LM-80 is a ‘lumen maintenance’ test procedure that is designed to indicate how quickly LED output declines to provide an indication of how long a product will remain fit for use.

3. Colour temperature

Colour temperature is measured in Kelvin. About 2700 Kelvin produces a nice warm light and about 4000 Kelvin would produce a bright noon-like light. Lights in our catalogue give you a wide variety to choose what’s best suited for the purpose.

 

Top tip = Knowing what colour of light you like is important – 'white' is not always 'white'.

colour-temperature

4. Colour rendering

 The ability of a light source to represent a natural light source is measured by the colour rendering index (CRI). For a good representation the index should be about 70-80. All our lights are >80 -  this is especially good for office lighting. This also impacts the appearance object colours - if the CRI is too low a loss of colour information occurs, and different colours will begin to look the same. 

Top tip = Always ask your lighting supplier to give you the CRI of the light

 

led-CRI-1

5. Rated life

 This is commonly a statistically determined estimate of median operational life – the rated average life. Many LED manufacturers boast of a long life for their products. An LED lifespan normally ranges 35,000 – 50,000 hours - that’s roughly 10-20 years depending on how long they are used. That is 50x longer than a traditional incandescent light.

This also relates to the lumen depreciation. The potential life span of an LED could be potentially longer, but after 50,000 hours it’s lumen output drops below a standard fit for use.

 

Top Tip: don't be fooled by long rated life promises (e.g 100,000 hours)

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