Wednesday, 26 September 2012

Halogen V LED V CFL

Halogen V CFL V LED

It seems the low energy lighting industry is changing week on week. Originally the next great thing to replace the halogen GU10 would be the CFL (compact fluorescent) version. No sooner had these been introduced it seemed the next stage of bulb evolution was already forming in the shape of the LED GU10. It took the LED a while to reach a decent enough standard but now it seems it is finally there.

So I thought it would be a good time to compare these 2 technologies against the original halogen. After all it is a bit of a minefield trying to choose what is best when buying bulbs (or lamps). There is so much to consider. Where are these bulbs going to be fit? Are they for downlights, spotbars, wall lights? Are they for decorative purposes or for proper illumination? Will the lights be left on for a long time or will they be occasionally activated?

First things first lets start by comparing the 3 physical shapes of the bulbs

On the left is the original Halogen GU10 (similar in size and shape to the 12V equivalent) This type of bulb has been around for a long time and a large percentage of spotbars and downlights (including the ones probably in your own home) and designed to accommodate this type of bulb. You can see from the image that the LED GU10 in the middle is very similar in size to the halogen. This makes it quite easy to replace exisiting halogen GU10s with the LED versions. They should fit fine in to most recessed downlights and spotbars. The CFL version on the right is a physically longer bulb. The diameter may be the same as the Halogen and the LED but the length is longer (some lower wattage CFL bulbs have a smaller length but the 11w, which is the closest to a normal light output, is the same length as the comparison above) This means that quite often you cant simply replace existing halogen GU10s with CFL versions. They stick out of spotbars making them look unsightly and existing recessed downlights dont often have the room inside to accommodate the extra length of the bulb. Recessed downlights that accommodate CFL bulbs are usually designed to allow them to fit (they are longer than normal recessed downlights). Dont make the mistake of buying CFL GU10s and assuming they will fit your current downlights in your ceiling. You may be disappointed.

Power consumption
The typical Halogen GU10 is a 50W. This means it uses 50W of electricity. This figure has nothing to do with light output (I know we have all grown up associating wattage with how bright a bulb is but this has always actually been wrong) Use the wattage of a bulb as a guide to how much power you are using (and therefore how much money it will cost you to run it). A typical LED GU10 will be anywhere from 3w to 7w. The standard CFL GU10 will be around 11w. The Halogen is 50W. This gives you a good idea on the cost of running the 3 bulbs. The LED should be cheapest followed by the CFL then followed way behind by the Halogen. Now think how many bulbs you currently run and you can soon see how much power you are using (and therefore how much money you are paying to light your home). Of course what can put some people off is the....

Price of each bulb
A typical halogen GU10 can cost you anywhere from £1.00 to £5.00. The LED can cost from £10.00 to £25.00. The CFL from £6.00 to £18.00. The cost of both the LED & CFL has always been a factor in putting some people off from changing to this technology. If you are trying to make an informed choice you need to try and look beyond this (I know its hard, especially if you have a lot of bulbs to replace). The way to look at it is the 5w LED uses a tenth of the power and therefore costs a tenth of the price to run than a halogen. Calculate this over a period of a few months and you can see that you very quickly make back the money they cost in savings on your electricity bill.

Light Output
The light output of the 3 examples above are all measured in Lumens. The 50w halogen emits around 800 lumens of light output. The LED emits around 400 lumens and the CFL emits around 240 lumens. The halogen is the brightest followed by the LED and then the CFL. It is therefore a good idea to over-estimate the number of recessed spotlights you may install if using the LED or CFL options to ensure you have enough light output.

Can they be dimmed?
All 3 types can be dimmed however you should be aware that both the LED & CFL bulbs must be purchased as dimmable versions (there are plenty of non-dimmable versions out there). If you require dimmable LEDs and CFLs then make sure they say they are dimmable before buying. The halogens are always dimmable. Another little thing to consider is the actually dimmer you will be using. Bear in mind that the dimmer will have a minimum wattage it can handle (in the same way that it has a maximum wattage as well). If the dimmer switch says the minimum wattage shouldn't be less than 10w then you wouldn't be able to run a single 5w LED GU10 on the switch. This does catch people out from time to time.

Warm or cool white?
Both the LEDs and the CFLs are usually available in both cool and warm white. The cool white option usually gives off slightly more light output but the warm white has a more inviting glow (unless the clinical style of the cool white is what you are trying to achieve).

Heat output
The Halogen will get extremely hot when operated to the point where it will burn your skin upon contact. The CFL is much cooler and will allow you to touch the bulb which will appear warm but shouldn't burn your fingers. The LED will be completely cold on the front when operated and this is often what attracts people to LED however you should bear in mind that LEDs do generate plenty of heat and this is all released through the back of the bulb which will get very hot. 

Speed of full brightness?
The Halogen will emit full brightness the instant the light switch is activated. The LED version will also do this as well. The CFL uses a technology that requires the bulb to heat the gasses inside to reach full brightness. This can take anywhere from 5 - 20 seconds though once fully illuminated it should stay like this for the rest of the night if switched on or off.

All in all it is important to decide which type of bulb is best for your environment. The traditional halogen GU10 is expensive to run and not suitable for areas that require constant light (such as a bathroom during the night or a landing). There is also the real possibility that they may be fazed out in the coming years in the same way that many incandescent bulbs are at the moment. If at all possible I think it is probably best to avoid halogens. CFLs offered a good alternative to halogens but the technology has limitations. Problems with dimming and lower light outputs combined with larger physical size make it an outdated solution. LED appears to be the future of the lighting industry. Improving light outputs with an ever decreasing cost of purchase combined with a much smaller running cost point to the best solution