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GU10 Mini Review

By Crafty

GU10 technology

OK, traditional halogen GU10 lamps have several drawbacks. They give off tremendous amounts of heat, which makes them unsuitable for mounting where insulation is present. The light they produce is quite narrow. Many lamps dont give off light at more than 60 degrees. Hence the light is very focused and you need a lot of lights to light a small area, or there are a lot of shadows. Stand under these lights and you can feel the heat and the glare too, it is uncomfortable to work under. Halogen lamps are often used to keep food warm in commercial kitchens.

Alternative one: LEDs

So lighting manufacturers have been working on alternative methods of compact downlighting. The easiest to manufacture, and the first to come about was the LED GU10. This is a standard size GU10 lamp, with a cluster of LEDs in it. A typical cluster is less than 2 watts, one twenty-fifth the energy used by a 50 watt GU10. LEDs dont get hot, they are cool to touch when in use. They will also fit any standard GU10 fitting. However, LEDs have numerous drawbacks.

1. Light rendition:

The light produced by LEDs is a pure colour and is no good for any practical use. I purchased a “white” LED lamp, however, I was less than impessed by its rendition of white. It looks very blue. LED lamps by their nature only produce a VERY limited spectrum of light. Imagine shining a red light on a blue surface. Can you see the blue? No, it appears black due to there being no blue light to reflect off it. Now imagine shining a blue light around your room. Most of the surfaces wont appear the correct colour. This is what happens with white LEDs. Even putting my hand in front of the lamp, it was dimly lit. I think maybe an RGB light might produce a better light for general use, since it gives out red, green and blue, instead of just blue.

2. Beam width:

The beam width is very narrow, more so than with halogen GU10s. LEDs are very directional, and I cant help thinking “why not mount them on a curved surface?”

3. Dimming:

Not that you’d want to, but its worth a mention, LED lamps cannot be dimmed (or at least its not recommended).

4. Brightness:

Finally, LEDs are still not bright enough for general use.

My overall opinion of LED lamps: Still a developing technology, with a long way to go before they are suitable for general lighting use. Good for decorative purposes. Funky colour changing versions available.


Since the original article was written back in 2006, LEDs have come a long way. I am only writing this from seeing LEDs in use in commercial premises. But warm white LED lamps are now available, which give an acceptable colour for home use. Also a new type of LED is available known as luxeon. This type is noticeable due to it only having 1 or 3 LEDs in a GU10 capsule. It may also have a heatsink. The luxeon spreads its light much better than traditional LEDs. Cheaper LEDs are still available, which generally have 20+ LEDs. Dimmable LEDs are also available. LEDs are finally becoming a realistic alternative.

Alternative two: CFLs

A more recent development, compact fluorescent GU10 lamps are, in my opinion, the way forward in the near future. Unfortunately, it is impossible to cram a fluorescent tube AND its ballast/electronics into a standard GU10 lamp. CFL versions, therefore are 2cm longer. This is only a problem where the light fitting has a fixed lampholder, since it cannot be moved back. Where the lampholder is not fixed and there is some slack on the wire, the CFL can be accomodated. Two standard wattages are available, 9 watt and 11 watt. The 9 watt version was a more than adequate replacement for a 50 watt halogen.

One of my 9 watt CFLs in a standard fixed fitting:

Special fittings are available for these CFL lights. TLC direct is one supplier.  They sell fire rated fittings and standard fittings.

The benefits of CFLs are numerous:

Better colour rendition:

they give off a balanced white light, similar to daylight, which is ideal for working environments. I changed one light in my bathroom to a CFL, and left the other two as standard halogens. I noted that after looking at the CFL end of the room for 5 mins, then looking back at the halogen end, the halogen light looked very orangey, almost dirty. The CFL light is much cleaner. In time, more shades of CFL will become available, as shades of fluorescent tubes are.

Better beam width:

the light is spread over a bigger distance. I have fitted these in my bathroom, and found that I only needed 2 of these lights, whereas before i needed 3 standard halogens due to their narrow beam.

Unfortunately, CFL lamps cannot be dimmed, but the technology is emerging for switch-dimmable CFLs, which are dimmed by a succession of switch on-off signals. Its only a matter of time before this technology finds its way into GU10s.


CFLs are now available that can be dimmed using normal dimming technology. However some users have reported vastly shorter lamp life than that quoted by the manufacturers on dimmable models. Clearly the circuitry is not up to the job in some cases. If dimmable downlights are desired as CFLs, my personal recommendation is PL downlights (google this), where the control circuitry can be replaced with a dimmable version. Despite the cost of decent LEDs, I would definitely advise the purchase of them over CFLs, due to their longevity and increasing quality.

A couple of pictures for comparison:

L-R: Megaman 9 watt CFL, Morrisons 50 watt halogen, Unbranded 1.8w LED lamp.

Comparison table

Typical wattage 50 or 35 2-5 7-11
Heat damaging heat some heat from luxeons some heat but “cool running”
Beam quality less than 60 degrees good beam from luxeons very wide beam
Light quality good colour but hot beam a range of colours available cool white light
Can be installed in insulation? No yes yes
Can be dimmed? yes some some
240v or 12v both both 240v only
Ideal use display light room light long running room light



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