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Our table lamp with a 4 watt LED bulb.
A decent light for working near on the compter,
while giving a decent saving on electricity over our previous lamp. |
We all want to pay a little less for electricity and/or cause a little less CO2, and help to do our bit, but most of us aren't ready to "put on the hair-shirt" just yet.
We want our luxuries, and see them as one of the hallmarks of our civilisation.
Indeed, for me, the three great marks of civilisation where I live are
1. The water that comes from the taps (faucets) is safe to drink
2. There is a decent public health system, so I can see a decent doctor if I am ill, without worrying about the cost.
3. Electricity is available at the flick of a switch, and it pretty much almost always works - our power locally is down for less, on average, than one hour per YEAR (based on only one decent power cut of 4 hours, and a few brief interruptions at night that cause the microwave clock to reset itself(!) in the 14 years I have lived in this town).
Still, we do all want to do our bit for "Global Warming" and/or save a bit of money on our electricity bills.
So here are a few ideas for you to think about, based on what we are doing.
Idea number 1: LED light bulbs.
We have started fitting LED light-bulbs into our various lamps. We had pretty much all of them fitted with Compact Flourescent tubes anyway, with just our rarely used interior porch light (there is a street light opposite our house!) having a "regular" spotlight bulb in it, and our table lamp next to this computer having a Halogen-type minature bulb with a wierd fitment.
Anyway, we decided to "make the switch", and have started purchasing LED bulbs.
As a result, that porch light now has an LED bulb (down from 60 watts to just 8 watts), and I use it more now, as I tend to switch the main room light (20 watts CF) off when I am putting my shoes on, using the porch light instead.
We have noticed that more powerful LED bulbs that would replace a 20 watt CF bulb (or a 100 watt "old-fashioned" filament bulb) are not very readily available, so this will be a long, slow upgrading process for us. As the CF bulbs fail, they will get replaced a few at a time by LEDs!
After the porch light, the other "old technology" bulb we had was the 10W bulb in that table lmap on the computer desk. It failed before Christmas, and a new bulb didn't fix the problem. After maybe 20 years, and a few falls, that lamp had had enough.
So a new lamp, bulb and fixture, it was, then.
An ideal time to switch to LED.
Now we run a 4 watt LED bulb in the new table lamp, and it is just as bright (if not brighter) than the "old" table lamp.
That lamp gets quite a bit of use, too, even in daylight, as the computer desk is in a shady part of the house!
So that's 10 watts down to 4 watts, with usage at between two and 10 hours a day.
Soon adds up!
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| 4 watt LED bulb from our table lamp |
So why are LED light bulbs better than the old light bulbs or the compact flourescent bulbs.?
The answer is easy - heat.
When I switch a light on I want it to make light with the electricity, not heat. the more the bulb heats up, the more light I am not getting for my electricity!
The old-type ("filament") bulbs (perfected, although not invented, by Edison - know your history!) work by heating a filament so hot that it glows white, and emits the light we see. So the bulbs get hot. Anyone who has even briefly touched a 60W bulb when it is on knows what I am talking about.
I used to have an old 16mm film projector with a 500 watt bulb in it, and that could heat a small room by itself when I was running film through it!
Halogen bulbs use essentially the same basic principle as the filament bulbs - a hot wire, so hot that it emits light. Where they differ is that a halogen bulb bas a special gas inside the bulb, and the "glass" is made from quartz. The combination of the special gas (usually argon on krypton) and the quartz glass means that the bulb can run EVEN hotter. The extra heat of the filament means that more of the energy is emitted as light, and less as heat, and these bulbs look whiter (or even blue-white) compared with "regular" bulbs. Vehicle headlight bulbs switched to Halogen types 40-odd years ago.
For "domestic" household bulbs, the quartz glass of the bulb is ofetn enclosed in a regular glass bulb as well, as the sweat on skin can affect the quartz. Smaller bulbs, like the miniature ones fitted to some table lamps and reading lights don't have the outer glass cover, and a pair of cotten gloves (or similar) should be used when handling the bulb.
From an energy saving point of view, Halogen bulbs are about twice as efficient as "regular" filament bulbs.
Compact Flourescent (CF aka CFL) lights use MUCH less energy than "filament" (Edison-type) bulbs, but some folks don't like the greenish tint they often give to the light, some folks are upset by the flickering that some CF bulbs seem to undergo, some folks don't like the way that many CF bulbs start off dim, then brighten up after a bit, and to be honest, they still get quite warm!
A 20 watt CF bulb gets quite a hot tube, but nowhere near as hot as a "filament" bulb of the same light output. The different spectrum of light output means that to the eye, the difference between a "filament" bulb and a CF bulb is big, but not quite as big as a lightmeter would show - the reason being that the human eye is more sensitive to yellow light than other colours, and the "old" bulbs produce a "yellower" light!
The common energy saving quoted for CF bulbs vs "filament" bulbs is 5:1, but, in practice, I have found that my eyes prefer a 4:1 ratio.
That means a 60 watt "old" bulb should be replaced with a 15 (-ish) watt replacement, rather than the 12 watts that bulb makers generally claim.
But 4:1 is still a CONSIDERABLE saving on electricity!
LED lights produce a more yellow colour of light, and with their almost instant start-up they produce pretty much full light as soon as switched on.
LED lights tend to have an efficiency improvement on the "old" type lights of 5:1 to 6:1, but because of their more "yellow" light output, they can be replace an "old" bulb at that ratio (i.e. 8 watts replaced 40 watts, rather athn a 10 or 11 watt CF bulb) The problem is that LED lights in higher wattages aren't commonly available yet.
We use LED lights in our lower power applications, and have several. Three have "regular" bulb shapes, and are interchangeable with CF or "filament" bulbs.
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| 4 watt dual-LED bulb as used in our table lamp |
We have a 10 watt LED bulb in our floor lamp, an 8 watt LED lamp in our porch, and a 4 watt LED bulb in the table lmap next to this computer.
We also have several reading lamps that each have a non-replaceable 3 watt LED light in them, and they have a tightly focussed beam, and are great for reading in bed! The brightness of light that illuminates my book from that little 3 watt LED lamp is actually more than that from the main light in the room, but then, of course, the little reading lamp is only trying to light one small area, while the bigger lamp has to light an entire room!
Summary:
For the same amount of light, as perceived by the human eye, the approximate efficiency of the various types of lights are as follows:
Regular, filament, bulb: 60W (the reference level!)
Halogen bulb: 30W
Compact Flourescent bulb: 15W
LED: 10 to 12 W
In each case, I have given an equivalent for the same usage of the bulb.
A spotlight gives a more focussed beam, and should be considered against other designs of spotlights, rather than "general" lights, or the bulbs for "table" lamps.
Of course, part of the solution is to choose the most appropriate light fitting in the first place - a little reading light at the bedside is a much better way to read in bed than lighting the whole room to the same level of illumination!
