CONDUIT 5: Home Lighting - LED Lighting (2)

28-09-2015

As promised in the previous issue of The Conduit magazine, published here in Sherborne, here I take a further look into the world of LED lighitng and the trend for 'retro-fit' lamps - those light sources designed to replace conventional tungsten, tungsten halogen and compact fluorescent (CFL) lamps.
Here I talk about the reflector lamp versions, with particular reference to those intended to replace all of those 50W tungsten halogen lamps beaming down from everyone's ceilings these days.

Here's the text:

Last time out I wrote about the new LED light bulbs that are appearing everywhere, though few of us know much about what they do. This time (as promised) I’m looking at the replacements for those little critters that you may well have peppering your kitchen ceiling, and your living room, dining room, bedroom, bathroom . . . you know what I’m talking about; It’s the recessed downlight!

I have to admit to some history here because I was working for a lighting manufacturer in the early 80s, when a brand new lamp came along (lamp = bulb in my world; please remember that), the like of which none of us had seen before; it was small, it was sparkly, it was (for the times) more energy efficient. The tungsten halogen (t/h) reflector lamp had arrived and what was there not to like. We all went mad for it and so the transformation of Home Lighting began.

There’s no need for me to talk about what these chaps do; they lurk in the ceiling, highlighting (or completely missing) the furniture beneath them; lighting (or not lighting) a room with little regard for what might be going on in the room. I admit – I don’t like them because I don’t approve of the way that they’ve become the default lighting for so many houses – it was never meant to be that way.

Still – that’s what we’ve got and now we’re looking at ways to reduce a kW’s worth of kitchen lighting to something a bit more respectable – hence the arrival of a new generation of low energy light sources.

First, let’s dismiss the fluorescent (CFL) alternative to the tungsten halogen lamp; they are available and they are rubbish – as many of you have found out. It’s a light source that was never designed to act as a spotlight, whereas the t/h reflector lamp was only ever intended to do exactly that job. So let’s forget CFL from the off.

The LED, on the other hand, is a natural spotlight. Light is emitted in one direction only, so all that’s required of the technologists is to decide what kind of light beam is required; a wide one, a narrow one, one shaped like a rabbit – you choose! All LEDs operate at an extra-low voltage so will need a piece of electronica for them to work. Sometimes that circuitry is inside the lamp housing itself, though I don’t approve of that because it causes thermal stress on the whole thing and that risks early failure . . . early adopters may already have experienced that.

There are many, many, disappointed people out there who’ve tried LED lamps, only to find their homes plunged into an energy-saving gloom. It doesn’t have to be this way, but always be on your guard. You’ll need at least a 7W LED lamp to get close to the performance of a 50W t/h lamp, and that will ultimately depend on the width of the light beam (wide-beam lamps cover a greater area but are not as bright as a narrow-beam lamp of the same wattage which, obviously, covers a smaller area).

So: my first recommendation if you want to replace your t/h reflector lamps is to use LED lamps that require –and are supplied with – a dedicated ‘driver’ (that’s the electronica that makes it all happen).

Hmmm, I hear some of you say that you’re using mains voltage t/h lamps that don’t require a transformer. Yes, there is an LED replacement and - no - it doesn’t alter my argument against integral electronica. If that’s what you have, then change the downlight fixture as well as the lamp. That’s my second recommendation.

LED companies are usually putting information on their packaging telling you what the LED performance is like and how it compares to its t/h forebear. Pay attention to this because it’s important that you understand how the new lighting will work for you. Best of luck!

To read the article in the magzine, click on the cover image: