Switching to LEDs

One thing that never gets mentioned when people talk about going to energy efficent light bulbs, is that whilst you are saving on electricity,you actually spend more on heating as you taking away a heat source and this naturally needs to be replenished.

Smacks of peter robbing to pay paul tbh.
 
wohoo said:
One thing that never gets mentioned when people talk about going to energy efficent light bulbs, is that whilst you are saving on electricity,you actually spend more on heating as you taking away a heat source and this naturally needs to be replenished.

Smacks of peter robbing to pay paul tbh.
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Only during winter.
If you lived in a perminantly cold country then yes energy efficient bulbs are pointless, but we don't.
 
Nash said:
In realistic terms, how much heat do lightbulbs give off then? :confused:
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If LEDs generate the same amount of light from 20w as a 60w bulb then it stands to reason that the remaining 40W is lost as "other" energy - mainly heat.
 
What he says.

Besides, since (barring localised convection effects) heat tends to rise, losing 50-80W/room of heat energy at ceiling level by replacing a house full of incandescent lighting with energy savers isn't going make a whole heap of difference.
 
DRZ said:
If LEDs generate the same amount of light from 20w as a 60w bulb then it stands to reason that the remaining 40W is lost as "other" energy - mainly heat.
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You're getting confused between light output and wattage, these led bulbs use a lot less than 20w, more like 3 or 4. The output of the lesser ones is about the same as a 20w bulb.
So you're actually looking at 55w less heat compared to a normal 60w bulb. Although you would need two or three led bulbs to replace one 60w bulb in terms of light output, because for some reason they can't seem to get enough light output into a singe bulb.
 
Those MR16 fittings with the 5mm LEDs pictured above aren't particularly bright. Each 5mm LED probably uses around 70mW so if you have 20 5mm LED's in there it will only use around 1.4W of power. This will probably be a similar amount of light to a 5W incandescent bulb which isn't really that bright. If you want more high power LED's, check out some of the Luxeon LED's. They do 5W ones now, but they do get rather warm so need heatsinking. These give out a similar amount of light to a 15W incan. If you look around, you can get Luxeon LEDs which include fittings and power converters for household use as they have been around for a while. These are much brighter but are more expensive.

EDIT: Here we go... high powered LED's in an MR-16 fitting: http://www.led-bulbs.com/eShop/10Browselux.asp?Category=Luxeon I'd guess the top one would be similar to a 35w halogen. It would be nice to compare then side by side to know for sure tho.

If you want the best efficiency, CREE have released the XR-E LED a few weeks ago. amazing efficiency. outputs light than a Luxeon III with less than half the power, and barely gets warm. It outputs over 100 lumens at 3.3v and a current of 500ma if that means anything to you. This is the current king of high power LEDs at the moment, but it will take a while before you can get them in standard fittings like MR-16's however, they have yet to hit the mainstream like Luxeons. If you are willing to do some soldering, you can do it yourself... you'll need a power converter, and reflectors or optics for the XR-E.

I like LED's... The last for ages so you don't have to worry about bulbs blowing. They are improving all the time (a bit like computers), and in a few years they will be even brighter and using even less power and running even cooler. :)
 
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locutus12 said:
Phillips are investing heavily in LED tech for street lighting :)

click here
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Proof, if it were needed, that its not technology holding back domestic led bulbs.
Traffic lights and lampposts should have changed to leds 5 years ago if this government were serious about climate change and not wasting energy. Instead they prefer to tax us rather than invest in better technology.

I have no idea what sort of power a street light uses, but say they currently use 100w. I would expect an led bulb to reduce that to say 20w, probably much less. With literally millions if not billions of street lamps in the uk, imagine the energy saving from that? You could probably close down a power station.

Edit: Heres some figures:
wikipedia said:
In countries such as France, Germany, Belgium, UK and the northern part of the US, street lamps are burning an average of 4000 hours per year. Considering that the average wattage of a lamp is around 150 watts, considering that a 100.000 inhabitant city contains about 18.000 lamps, such a city spend around 11Giga watt.hour (11 billion watt hours). Considering that producing 1KWH implies the emission of 340 grams of CO² (average in Europe), the streetlights of such a city is responsible for the emission of 3700 tons of CO² in the atmosphere per year.
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Thats interesting, I've always understood it that the sodium bulbs in normal streetlamps are very efficient anyhow. Perhaps this is more to do with LEDs mabye lasting longer or getting something other than that deep orangey colour?

We were always told in physics ordinary bulbs emit around 10% light, 90% heat, which is pretty terrible.
 
I'm pretty sure that led bulbs, if done right, should be better than sodium bulbs. I'll see if i can find some facts though.
 
Joe42 said:
Only during winter.
If you lived in a perminantly cold country then yes energy efficient bulbs are pointless, but we don't.
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It all adds up, and its just not domestic application, commercial and industrial applications also need light and heat.

Its the old addage Energy isnt 'lost' its just converted into another form, and if a 'body' requires a certain amount of heat and you take that away, you have to replenish it somehow and yes it may be a miniscule amount, but realisticly so is the saving you are making from switching from filament to energy savers, as they cost much more than your std filament bulb.
 
wohoo said:
It all adds up, and its just not domestic application, commercial and industrial applications also need light and heat.

Its the old addage Energy isnt 'lost' its just converted into another form, and if a 'body' requires a certain amount of heat and you take that away, you have to replenish it somehow and yes it may be a miniscule amount, but realisticly so is the saving you are making from switching from filament to energy savers, as they cost much more than your std filament bulb.
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Gas heating is 1/4 the price of electric heating and probably 4 times more effiecient than electric :D
 
The gap isnt as great as that now, and in any case the bulb isnt an electric heater, basically the way i see it vhanging to environmentally efficient bulbs means going to an inferior product for a percieved saving.
 
wohoo said:
The gap isnt as great as that now, and in any case the bulb isnt an electric heater, basically the way i see it vhanging to environmentally efficient bulbs means going to an inferior product for a percieved saving.
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Not quite sure what you're smoking...
A bulb is a device to produce light. How is a bulb which produces the same amount of light with less heat inferior?
As mentioned, the heat produced by less efficient bulbs is only useful half the time, during summer it just adds to air con bills or is wasted as its unwanted, so you are paying for power to produce heat you don't want.

You try telling business that the cost of buying these efficient bulbs outweights the savings... i've yet to see a business which doesn't use almost exclusively tube lighting.
 
Joe42 said:
Not quite sure what you're smoking...
A bulb is a device to produce light. How is a bulb which produces the same amount of light with less heat inferior?
As mentioned, the heat produced by less efficient bulbs is only useful half the time, during summer it just adds to air con bills or is wasted as its unwanted, so you are paying for power to produce heat you don't want.

You try telling business that the cost of buying these efficient bulbs outweights the savings... i've yet to see a business which doesn't use almost exclusively tube lighting.
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Yeah let's have some of what your smoking :eek:
 
Joe42 said:
You try telling business that the cost of buying these efficient bulbs outweights the savings... i've yet to see a business which doesn't use almost exclusively tube lighting.
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Fluorescent tubes are more efficient than HID lights and LEDs right now. This is why they are used so much.
 
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