Introduction to Electry efficient lighting page 2/2
Choosing the compact fluorescent light bulbs
As I said before, you can find CFLs (compact fluorescent light bulbs) which cost about five to ten times more than ordinary incandescent light bulbs. But there are also those that cost twenty or even thirty times more. The higher price does mean better quality, but if you plan to use them for general lighting as I suggest, there is really no need to pay so much more for a little improvement in the quality of light. Usually shops where you can find cheap incandescent light bulbs (the normal ones) also have cheap CFLs and vice versa. See the bottom of this page for more ideas on where to buy. Here are things you should consider when buying CFLs.
The amount of light
The amount of light coming from a light bulb is measured in lumens. Energy efficient lighting is all about getting more lumens per watt. Usually if you have two similar bulbs the one with higher energy consumption will usually give more lumens per watt. This might seem complicated, but look at it this way. If you have two 50W incandescent bulbs and replace them with a similar kind that is 100W, you usually get more light. Or you can replace two 60W bulbs with a 100W bulb and get the same amount of light with less energy.
If you wish to replace a 60W incandescent bulb with an energy saving alternative, you need to look at lumens instead of watts. Energy federation incorporated has a handy chart you can use to see how much light you can expect to get from compact fluorescent light bulbs compared to incandescent bulbs. Click here to read the chart.
Most manufacturers say the energy consumption is only 20% compared to standard light bulbs. Most of the time this is simply not true. The package can say for example: "11W = 60W". If you see something like that on the package, don't believe it. If you compare the amount of light coming from a 11W compact fluorescent to a standard 60W bulb, you will notice a significant difference. With the really expensive 11W ones you might get the same amount of light as from a 60W bulb, but there is not much point in paying so much extra for a bulb that might or might not give more light. Instead you can simply get a cheap one that is a bit more powerfull. Whether you use a 11W or a 15W compact fluorescent doesn't really make much of a difference anyway as far as energy consumption is concerned. The difference is only 4 watts, but it will definitely give you more light. So don't get hysterical about saving energy with lighting, even if you get the bigger one and replace a 60W bulb with a 15W for example, you will still save 45 watts which is 75% (otherwise you might not be happy with the amount of light and
might even go back to using the 60W incandescent bulbs).
Especially if you are buying a light bulb for a fixture with a small base (E14 in Europe, E12 or E10 in America) you should buy the biggest one you can find. Otherwise you might end up not having enough light. Many stores only sell CFLs with really low wattage for bulbs with the smaller base - like 7 watts or less. Don't expect to get too much light out of those - if you can find a more
powerful one, buy that one instead.
NB. There are also long-life bulbs on the market that are NOT energy efficient at all. These are in fact even less efficient than ordinary incandescent bulbs. Avoid these long-life bulbs and use compact fluorescent light bulbs instead. With normal use of four hours a day, a compact fluorescent light bulb will last for years and use only a fraction of the energy (10,000 hours / 4 hours per day = 2500 days = 6.8 years). Even ecologically conscious stores like RealGoods sometimes sell these
inefficient long-life bulbs.
Compact fluorescent light bulbs are often bigger than standard incandescent light bulbs and a big one might not fit into your fixture. Sometimes the longer head of the light bulb can also stick out from the fixture and irritate your eyes as it is in plain sight. Many of the more expensive ones have
spiral shaped tubes instead of straight tubes as in the cheaper models. There are also newer CFL models which have thinner tubes inside and are shaped like traditional incandescent bulbs.
The color of the light is measured in Kelvins and is called color temperature: 2,700-3,000K will give a warmer white light and 4,500-6,000K will give a cooler white (lower temperature for warmer color - not the other way round as you might expect). The cheap models usually have a low color temperature and a warm color. Higher color temperature, sometimes called "daylight", usually means better color rendering, which is one of the reasons you might want to try one of the more expensive models. But as I said before, even the cheapest ones are fine for general lighting. For more information on color temperature visit http://www.efi.org/factoids/colortemp.html
Color rendering refers to how natural colors look in certain lighting conditions. The higher the color rendering index the better. If you use compact fluorescent bulbs for general lighting, you don't need to be too concerned about color rendering. Most cheap models don't even tell you their color rendering index and if you don't see it on the package you can expect it to be low.
Color rendering comes more important when compact fluorescent bulbs are used for reading or other work which needs good lighting conditions. Even if colors are not important for your work, it is still worth taking a look at the color rendering figures. Good color rendering means the light bulb emits light on a broad spectrum - in other words it emits all kinds of colors which together make the white light. Cheap compact fluorescent bulbs only emit light on few frequenzies (a narrow spectrum). This kind of lighting can be more straining to the eyes and should be therefore avoided when reading etc.
Broad spectrum lighting is sometimes called daylight, but most of the time this refers to the color temperature and these bulbs might not have a broad spectrum at all. If you want broad spectrum light, make sure the package says "broad spectrum" or "full spectrum" - not just daylight. If the light has a broad spectrum it will also have a good color rendering index (CRI). A real full spectrum light will have both a high color temperature (about 5000-6000 Kelvin) and a high CRI (90 to 100).
There are real broad spectrum compact fluorescent light bulbs available, but these do cost some extra. These will be discussed in more detail later when we take a look at lighting solutions for reading.
Many of the cheaper compact fluorescent bulbs will break if the electricity is not steady. Normally compact fluorescent light bulbs last for years. Even with constant use they should last a whole year. If your compact fluorescents break soon, this can be due to voltage fluctuations in the electricity. The cheap models are sensitive to fluctuations in the voltage, but this is not a problem with many of the more expensive ones. If you suspect your electricity might not be steady and want to try a more resistant model, you should go to a specific shop that sells lamps and ask for a compact fluorescent bulb which is not sensitive to electric fluctuations.
The expensive ones are not quite as fragile, but if you don't hit the lamp and your electricity is ok, there should not be much difference in the durability. I have used cheap compact fluorescents for about seven years now and during this time I have seen only two compact fluorescent bulbs break in normal use (and broken two with improper handling - to avoid these mistakes see "Where and when to use electry efficient lighting" on the previous page.).
Disposing compact fluorescent light bulbs
Compact fluorescent light bulbs have mercury in them and they must be disposed properly. Luckily almost all of the material can be recycled and it is just a matter of getting them to the right place to be recycled.
The above info is for the long fluorescent tubes, which contain more mercury than CFLs but still...
Where to buy compact fluorescent light bulbs
Where to buy compact fluorescent bulbs depends greatly on which kind you are looking for. If you need the cheap ones, look in your nearest supermarket. The prices are often several times cheaper than in specialized lighting stores. You might not find any models with a spiral shaped tube or with good color rendering - those are things you will have to pay for.
For better quality compact fluorescents see your local lighting store, or buy from the internet. You can start from
Gaiam / RealGoods for example.
Other lighting solutions for reading and working
Many people use electryefficient lighting for reading without even realizing it. Many of the desk lights from Lival for example have a compact fluorescent tube like Dulux S 11W from Osram. If you look at the bulb closely, you will see it is quite similar to an ordinary compact fluorescent bulb - the tube is longer and there is a different kind of socket. Basically it is the same, and all the above info about handling and choosing compact fluorescent bulbs also pertains to these compact fluorescent tubes. The only difference is, that as reading and working require good lighting conditions, you should pay more attention to the quality of light.
A common problem with low quality fluorescent tubes is flicker. Flicker is really annoying and straining to the eyes, but luckily many of the newer models have eliminated the flicker almost completely. The tubes can also start to flicker when they are worn out. Therefore if you have a desk lamp made by Lival and it flickers, it will probably become ok when you replace the tube.
As long as there is no flicker, the light quality can be really good as some compact fluorescent tubes have excellent color rendering.
You can also find some energy efficient reading lamps from
Gaiam / RealGoods for example: