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If fluorescent light bulbs are 3 times more efficient than incandescent bulbs

S

Staples

Diamond Member
I have use compact fluorescent bulbs in my house forever. I use them because they save on the electricity bill and they (at least I hope) keep the room a little cooler.

The boxes claim that a 25watt fluorescent bulb emits the same amount of light as a 75watt incandescent bulb. I have always wondered if that means that they also produce 1/3 the heat as a 75watt incandescent bulb. Anyone have any idea? Are they even comparable in terms of heat production because they burn at different temperatures?
 
watts are a measure of POWER, not heat. Also, the argument that it all goes to heat in the end is just silly since we all know that everything "eventually" goes to heat, what matters is that the energy is converted to visible light which is usefull. The fact that this light is eventually absorbed and radiated as heat has absolutely no effect of the efficiency or utility of a lightbulb.
 
I found Wikion Wiki(sweet sweet Wiki)

Approximately 95% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light. An incandescent light bulb, with this ~5% efficiency, is about one quarter as efficient as a fluorescent lamp (about 20% efficiency), and produces about six times as much heat with the same amounts of light from both sources. One reason why incandescent lamps are unpopular in commercial spaces is that the heat output results in the need for more air conditioning in the summer. Incandescent lamps can usually be replaced by self-ballasted compact fluorescent light bulbs, which fit directly into standard sockets. This lets a 100 W incandescent lamp be replaced by a 23-watt fluorescent bulb, while still producing the same amount of light.


So that fluorescent bulb gives off 1/6th the heat as the normal bulb.

I need to find a 75w fluorescent bulb to replace my 300watt halogan lamp.
Maybe that will help cool my room instead of a space A/C unit.
 
Originally posted by: BrownTown
watts are a measure of POWER, not heat. Also, the argument that it all goes to heat in the end is just silly since we all know that everything "eventually" goes to heat, what matters is that the energy is converted to visible light which is usefull.
Click to expand...

"silly"? When you're calculating things like heat load for your cooling system, it's good to know that 100% of the wattage rating of all the bulbs in the room will go to heat, which has to be removed, unless you have giant windows that allow the light to escape. Same thing for your computer, your TV, etc. No matter what kinds of other uses you're getting out of them, they're also functioning as space heaters. I made no claims as to the lighting efficiency of the two bulbs.
 
Originally posted by: jagec
Originally posted by: BrownTown
watts are a measure of POWER, not heat. Also, the argument that it all goes to heat in the end is just silly since we all know that everything "eventually" goes to heat, what matters is that the energy is converted to visible light which is usefull.
Click to expand...

"silly"? When you're calculating things like heat load for your cooling system, it's good to know that 100% of the wattage rating of all the bulbs in the room will go to heat, which has to be removed, unless you have giant windows that allow the light to escape. Same thing for your computer, your TV, etc. No matter what kinds of other uses you're getting out of them, they're also functioning as space heaters. I made no claims as to the lighting efficiency of the two bulbs.
Click to expand...

Windows trap heat. How do you think Greenhouses work?
 
interestingly, when you turn on a fluorescent light, the started consumes as much power as it takes to run the light (once started) for 20 minutes. So, if you're going to leave a room for less than 20 mins and it has strip lights, don't turn the lights off to save energy.

 
Originally posted by: loic2003
interestingly, when you turn on a fluorescent light, the started consumes as much power as it takes to run the light (once started) for 20 minutes. So, if you're going to leave a room for less than 20 mins and it has strip lights, don't turn the lights off to save energy.
Click to expand...

Do they have capacitors in them or something? How do they draw that much current all at once?
 
Originally posted by: mugs
Originally posted by: loic2003
interestingly, when you turn on a fluorescent light, the started consumes as much power as it takes to run the light (once started) for 20 minutes. So, if you're going to leave a room for less than 20 mins and it has strip lights, don't turn the lights off to save energy.
Click to expand...

Do they have capacitors in them or something? How do they draw that much current all at once?
Click to expand...

I can't rememeber. I just remember my physics teacher at A-level telling me. I'll read up on it.

Edit: yeah they have capaciters.
 
Originally posted by: AgentJean
I found Wikion Wiki(sweet sweet Wiki)

Approximately 95% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light. An incandescent light bulb, with this ~5% efficiency, is about one quarter as efficient as a fluorescent lamp (about 20% efficiency), and produces about six times as much heat with the same amounts of light from both sources. One reason why incandescent lamps are unpopular in commercial spaces is that the heat output results in the need for more air conditioning in the summer. Incandescent lamps can usually be replaced by self-ballasted compact fluorescent light bulbs, which fit directly into standard sockets. This lets a 100 W incandescent lamp be replaced by a 23-watt fluorescent bulb, while still producing the same amount of light.


So that fluorescent bulb gives off 1/6th the heat as the normal bulb.

I need to find a 75w fluorescent bulb to replace my 300watt halogan lamp.
Maybe that will help cool my room instead of a space A/C unit.
Click to expand...

if you must have a torchier lamp they do make 250-300watt flourescent versions. well they use like 55watts or so... personally i prefer multiple smaller cf light sources. i've seen some addon round circle ring ones with normal light bulb screw in socket at that wattage too, no dimming ability though. there are others that do dim. but yes, 23-25watt =100watt light output equiv, not 75.
 
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