Posts Tagged ‘How to choose LEDs’
Ever since the incandescent lamp was technically banned in 2009 and strict building regulations have been enforced the lighting industry has been tripping over its heels to produce the most energy efficient and cost effective lighting with each manufacturer fighting to get their foot in the door…
This intense need for viable replacements of a light source that we have been happy with for over 100 years has meant that the market is now flooded with a vast array of LEDs, so much so that the average consumer can be completely flummoxed by the choice.
Most electricians now are accustomed to fitting dedicated LEDs and most are more than happy to pull out the latest ‘answer to all your problems’ in the form of their favourite LED downlight. However, before blithely committing to a house full of your electrician’s recommended downlights it’s important to assess exactly what you are getting so you can make an informed choice.
LED’s come in a range of colour temperatures and it is important to verify the Kelvins in order to assess the warmth. Many manufacturers will produce LED’s at approximately 4000°K as standard and will refer to an LED fitting as ‘Warm White’ when it is 3000°K (more like tungsten halogen). This version of Warm White is fine for accent lighting, e.g. small uplighters, washing down onto steps and even in contemporary kitchens and bathrooms where a crisper cooler light can work well; however, for downlights in areas such as living rooms and bedrooms going for temperatures around 2700°K is much warmer and more akin to the light you will get from the old fashioned incandescent lamp. While some contemporary properties could get away with the standard ‘Warm White’ throughout the house I would recommend that when incorporating LEDs in a classical property the warmer white is chosen otherwise the effect can be harsh and not in keeping with the interior.
I tend to use 2700°K inside and 3000°K for gardens and landscapes.
This is a process that the manufacturer goes through when categorising the colour temperatures of the LEDs. The diodes can vary slightly in their colour temperature, especially from batch to batch, with the best quality LEDs varying to a lesser extent. Reputable manufacturers will follow a stringent process of ‘binning’ – in other words grouping all the LEDs together so that the consumer can be sure that all their light fittings will match in terms light colour temperature. This is why it is important to buy from a quality manufacturer as the slightest variation at the time of installation will only increase over the years – as will your frustration!
Colour Rendering Index
The Colour Rendering Index (CRI) indicates how the colours of an object are reproduced when illuminated by a light source. The sun gives a CRI of 100 and naturally our eyes are adapted to this so in order to perceive a true colour, the closer we get to this figure the better the quality of colour. Details on standard LED’s will often omit this important piece of information but generally over 80 CRI is good. When lighting artwork however, a CRI of over 90 is going to give the best effect and we will normally specify 95+ CRI for this purpose.
How many people have put in LED’s throughout their homes only to realise that they can’t dim them! From any lighting designer’s point of view the one most vital element you need to create the right ambience is dimming. Don’t believe that LED’s won’t dim – they will if you get the right product. However, you need to check that the dimming facility on the driver (transformer) will ‘speak’ to the dimmer that you select. It’s not complicated; it just needs to be verified at the time of specifying.
Are LEDs the answer to our prayers? This remains to be seen. Not enough time has passed yet with the products in the genuine market place to establish whether they are all they are promised to be. It is one thing to test a product in laboratory and yet another to incorporate it into a living environment with all the foibles of modern living. How can you be sure that what you are purchasing is up to the job? Do your research and go for reputable manufacturers, just as you would if you were purchasing a car or another major piece of technology. These lights should be with you for a good number of years and it is best to avoid the frustration and expense of replacing them before they have reached their perceived life span.
If you don’t want to go to the expense of high quality dedicated LED fittings there are some excellent retro fit LED lamps now available and combining these with appropriate fittings can be an effective solution. Again, go for products from good quality manufacturers – check colour, dimming, life and CRI if appropriate and remember the adage “buy cheap, pay twice”!