Seeing the Light Testing energy light bulb claims
How many Anarchists does it take to change a light bulb? – It doesn’t matter, Anarchists won’t change anything. This might be one of our editor’s better jokes but at least we can change it now for everlasting light bulbs that use no power.
I know there are more pressing problems in the world right now but I’m sick of sitting in the gloom while someone tells me the dim fluorescent light bulb is supposed to be equivalent to 60 watt when it so obviously isn’t. This made me wonder how honest the rest of the energy and money saving claims were as I was starting to think it was all bollocks.
There are two main problems with the normal ‘savings’ figures. The first is the life of energy saving bulbs. This is usually put at eight times longer than the old style ones. Now I had a mad environmental moment in B & Q two years ago when I bought rechargeable batteries, a recharger and a pack of energy saving light bulbs. Being a horder I kept the receipt so I know it was two years ago and I’ve had to replace all the bulbs since. If they last eight times as long that would mean I had been changing the old style, incandescent bulbs every three months which is not the case.
There could be a reason for the actual bulb life not lasting as long as the claims. Like most people that I know most of my light bulbs hang from the ceiling (although maybe not from such dust covered light shades). This makes the bulbs fail quicker than if they are set the other way up. This is something to do with the electric charge at the ballast (a sort of resistor thing). They also don’t handle temperature outside of normal room temperature range too well either, so if it gets a bit hotter or colder they fail quicker.
As far as my own light bulbs are concerned I’d say both types of bulb have the same life span in a house even if they don’t in the laboratory.
This brings problem two, that a 11 Watt fluorescent bulb equals 60 Watt old style. This is decided in lab tests where everything is perfect, actually better than perfect. They are often tested with different ballasts and voltage than used in a house and in these conditions fluorescents are 5 times better. Related to a house situation it’s really only currently 4 times better so outside the lab 11W = 40W not 60W. This is made worse by the type of light the bulbs give off. Old style have a more red spectrum where as fluorescents currently have a more blue spectrum which means the light is different, however what is measured for comparison is the intensity of the light to the human eye. This is measured in lumens which is actually based on candle light and does not distinguish between light from different spectrums.
On top of all that science, where as old style bulbs just ‘go’ fluorescents deteriorate and fade over time. They can also dim up to nearly 50% as it gets colder.
All of that means for 60W equivalent you really need 15W+.
With the re evaluated life and Wattage in mind we can look at the figures and see if the savings claim is bollocks:
A 60W bulb costs 15p and 15W fluorescents cost, well I can’t buy 15W in my local store only 11W or 20W so to get something like 60W I would need the 20W which is £2.80.
The cost of electric I’ve taken to be 20p per KWh (kilowatt hour). It’s about 15p at the moment but the way prices are going up it’ll be there soon. This means each hr costs 0.02p per Watt.
So for a 60W bulb that’s 1.2p an hour and for 20W it’s 0.4p
Both types seem to last two years in my house and with the main bulb on for an average of five hours a day that’s about 3500 hrs in two years.
In two years then a 60W bulb costs £42 (3500 x 1.2p) + 15p = £42.15
the equivalent 20W bulb costs £14 (3500 x 0.4p) + £2.80 = £16.80
I admit it, I was wrong. Although the claims are overstretched that’s still a saving of £25, about £12 a year, per bulb. Even for bulbs on for only an hour a day it’ll save you £1 a year per bulb which is enough for two cans of Lidl’s cheapest. Of course you can save even more if you use 11W bulbs but please don’t say they are the same as 60W or I’ll scream.
This article came from issue 10 of Now or Never To get a copy of issue 10 check out the Shop |
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