Energy-Saving Lightbulbs

24 Mar, 2008 | Science And TechnologyTdp

I've been meaning to buy some lower energy replacements for my halogen GU10 bulbs for a while, but I wanted to test the options out first. For those who don't know, GU10 bulbs are the standard halogen bulbs used in down-lighters and a lot of the small, modern room lights. We've got plenty around the house. They're very small and nice and bright, typically 50w. They also get very hot.

It means they're pulling a lot of power though, one room in the house has eight of them, equating to 400w of lighting. I did some searching and found that there are both CFL (compact fluorescent lamp) and LED (light emitting diode) replacement versions, both of which draw much less power. I bought some of each to see how they faired.


Compact fluorescent lamps are what most people understand as normal energy-saving bulbs, basically small fluorescent tubes that and small enough to fit into something that looks like a standard bulb. As the GU10 bulbs are very small, they seem to use a number of small U-shaped tubes. The ones I bought were Megaman bulbs, which seem to be pretty popular. I went for the 11w warm white versions, which equate to a standard halogen bulb in light output a colour. They are supposed to have a 10,000 hour life, but they are considerably more expensive than the standard bulbs (twice the price).

Having had them in for a couple of weeks now, I can say I am very pleased with them. The only negatives are that they take a while to get to full brightness, once there they are easily the match of the bulbs they replaced, but they do take five seconds or so to get to a point where you can see anything in the room and probably 30 seconds to get to full brightness. The other gripe is that while they fit in a standard GU10 fitting, they are much longer than the bulbs they replace and stick out a good 3/4 of an inch compared to the bulbs they replace.


LEDs aren't quite there for home use as replacement bulbs yet, but I thought I would take a look. The ones I got, from Innovation, where 1.2w white bulbs. I've had them in for the same time as the CFLs, running side-by-side. They don't claim to be as bright as a 50w bulb (you need probably a 3w or 5w version for that, but these are currently VERY expensive). I found several benefits over the CFLs, aside from the even lower power usage. They are the same size as the normal GU10 bulbs, so no problems with ugly protrusions. They also switch on at full brightness immediately, so no fumbling in the dark when you're in a hurry. Another plus though, the pack states they last up to 30,000 hours and they cost the same for two bulbs as one of the Megaman CFLs.

On the downside, they're no where near bright enough to use as the sole light source, they don't get anywhere near the brightness of the other bulbs and they don't seem to cast light in the same way either, rather focus it in one spot. I also have white LEDs, which show very blue, which looks odd compared to the other bulbs (there are warm white versions available I believe though). So, they're no quite there yet, but when 5w LED bulbs get cheaper LEDs looks like they could be a very good alternative for spot lighting tasks, although possibly not for normal lamps due to their directional nature (although this may change).

Light Colour

It's probably worth mentioning that the replacement bulbs seem to come in two colours (as opposed to standard bulbs, which usually only come in one). That is to say warm and cold. Anyone who remembers the old days of film photography may remember that film used to come in two types: indoors and outdoors. This is because natural daylight is a different 'colour' to the lights we use indoors. The light we use in buildings is typically referred to as tungsten and gives off a 'warm' light, which has an orange tint. Natural daylight has a much 'colder' temperature and appears to have a blue hue. Bear than in mind when buying bulbs and make sure you buy the right one.