Saving the World

[Мастер]

So one of my compact fluorescent bulbs has gone bad, I need a new one.

1,100 lumens, 18 watts. It was a bit of a shocker when I read that. Back in the dark ages of incandescent light bulbs, I used to get 60 or 100 or even 120 watt bulbs, for a roughly similar amount of light output.

So my initial reaction was to engage in the typical insufferable sort of self-congratulation that is commonplace. Look at me, I’ve reduced my energy consumption by 0.02% by using fluorescent bulbs! I’m saving the world!

Not actively harmful, like driving an SUV across town to drop off a few cans at the recycling centre. Just not very helpful. A pretty low impact activity.

But then I thought, does it really do any good at all?

After all, where did all the “wasted” energy of the incandescent bulbs go? It had to be heat. What else could it be? They’re not synthesising energy-rich chemical compounds. They’re not moving heavy rocks uphill. They’re not accelerating objects to a high velocity. It must be heat, no? And I do recall that the incandescent bulbs ran pretty hot; often painful to touch.

So this made me wonder, do the fluorescent bulbs really save anything at all? For me, yes - I live in the tropics, we don’t heat our homes. We don’t even have heaters installed. But what if someone is in Calgary or Murmansk in the winter? They’ll be heating their homes. Either the heater is hooked to some sort of thermostat, or they turn it off when it gets warm enough. So if these inefficient incandescent bulbs are wasteful because the produce so much heat, won’t this just reduce the burden on the heating system, by the same amount of energy?

Then I thought, well, I don’t really know. The electricity is produced and delivered with less than perfect efficiency, but so is natural gas. Which is more efficient? If the incandescent bulb replaces a certain amount of natural gas heating with electric heating, what is the net effect of that?

Would anyone like to illuminate these matters for me?

[tubeswell]

Yes, lower wattage light bulbs have a lower rate of power consumption. (1W = 1 unit of power = 1V x 1A = 1A^2 x 1R = 1V^2 /1R)

And yes, incandescent light bulbs dissipate a fair amount of their consumed power as heat, and they are relatively inefficient compared to (say) LED bulbs of the same luminosity.

[Enzo]

Context. You have an 18 watt device rather than a 100 watt device. WHile the amount of light it produces is of a practical concern to you, in this debate, power use is the key. It draws 18 watts from the grid instead of 100 to do the same job. SO whatever inefficiencies the power plant brings to the party, our CLF bulb uses only 18% as much. On your end, similar, your 18 watts is dissipated as heat and light. (Oh and possibly a tiny amount as mechanical energy/sound) SO you are also using 18% of what you used to use.

That may sound like double dipping, but wherever the inefficiencies lie, you will be using only 18% as much. Unused power won't be generated. I am not aware of any giant motors spinning just to use up unwanted excess electricity. So if the bulb in my home uses less to do its job, the power plant won't somehow use more to compensate. Net savings at each level.

[Мастер]

Context. You have an 18 watt device rather than a 100 watt device. WHile the amount of light it produces is of a practical concern to you, in this debate, power use is the key. It draws 18 watts from the grid instead of 100 to do the same job. SO whatever inefficiencies the power plant brings to the party, our CLF bulb uses only 18% as much. On your end, similar, your 18 watts is dissipated as heat and light. (Oh and possibly a tiny amount as mechanical energy/sound) SO you are also using 18% of what you used to use.

I agree with all that. My power consumption to produce a certain amount of light is lower.

The question is whether my total power consumption is lower.

If the inefficient incandescent bulb is inefficient because it produces heat, then that heat is released inside the home (unless the bulb is outside).

Now, for me, that means the home is hotter than it would otherwise be, and we run the air conditioner more. We don’t heat our homes here, we air condition them.

But in a home that needs to be heated, do you just run the heater the same amount, and let the home be hotter? Or do you run the heater less?

If you run the heater less, than the “inefficient” incandescent bulb may not be inefficient at all. It uses energy to produce light and heat. And if the heat reduces the load on the home heating system, then it isn’t a useless by-product - it partially substitutes for home heating.

That may sound like double dipping, but wherever the inefficiencies lie, you will be using only 18% as much.

For production of light, yes. Will everyone run the home heating system at the same level, and just let the home be hotter?

[Arneb]

I think the answers to this are quantitative, and they are also a bit imprecise.

The heat generated by the inefficiency of your light bulb heats the room, all right. It is certainly possible to heat your room with lights: When we light the 20 candles on our Christmas tree, I always have to let cool air in after the candles have burnt down because they produce som much heat. But the heating is it indiscriminate, wether you want it or not. If you live in conditions that require heating, you have little to gain because the (say) 80 Watts you lose as heat from a light bulb that draws 100 W is small compared to the several kilowatt you need to keep a room warm - especially in North America, where buildings lose a lot of their heat to the ourside world. And in situations where you don't need the heating, their heating effect is unwelcome (you, living in Singapore, even have to turn up the air con, and THAT is very energy-inefficient).

OTOH, I know people who just love their brightly-lit rooms. I can easily imagine people running 10 or 12 lamps at a time in a midsize-home in the evening - If you draw 240 W from twelve 20 W lamps instead of 1200, it adds up - at the 29 Euro cent we pay here for a kWh. And yes, I guess in winter all those light bulbs could give you an opportunity to turn down the heating a bit. But only at times when you need the heat.

So you can save money during more clement seasons, or by living close to the equator. Also, there are countries where fossil fuels are cheap while electricity prduced from them is not - bad housekeeping to heat your home with light bulbs instead of turning up the heat on the oil heater you filled with cheap oil.

Then of course, if you use the new lamps for a flashlight, the calculation is even more favourable: Buying a fifth of the batteries (=ineffecient, expensive, chemical electricity storing devices) surely is lighter on your pocket especially since flash lights aren't normally used to keep warm.

An artist had a lovely idea for this. When the EU banned 100 W light bulbs, he offered them as "heating elements; just put them into a socket usually used for lamps, and not only will they keep you warm, they will also produce a bright, warm, comfortable light". And the piece of art was, he was actually allowed to sell them as heating elements.

So yeah, you could save a notch on your heating costs, under certain circumstances. Still, the 18 W replacementws are probably a good idea under most conditions.

[Lianachan]

We are Brexiting soon, and these issues will become a thing of our past as we concentrate on how to heat and light the caves we live in.

[Arneb]

Well, at least now you know that much, fire is good at both...

[Lianachan]

Well, at least now you know that much, fire is good at both...

My understanding is that this “fire” can also be used for cooking. What technology! Exciting times ahead.

[Мастер]

The heat generated by the inefficiency of your light bulb heats the room, all right. It is certainly possible to heat your room with lights: When we light the 20 candles on our Christmas tree, I always have to let cool air in after the candles have burnt down because they produce som much heat. But the heating is it indiscriminate, wether you want it or not. If you live in conditions that require heating, you have little to gain because the (say) 80 Watts you lose as heat from a light bulb that draws 100 W is small compared to the several kilowatt you need to keep a room warm - especially in North America, where buildings lose a lot of their heat to the ourside world. And in situations where you don't need the heating, their heating effect is unwelcome (you, living in Singapore, even have to turn up the air con, and THAT is very energy-inefficient).

Agreed that the incandescent is inefficient if you don't want the heat (definitely the case for me here).

I am not arguing that there is some sort of advantage to the incandescent bulb - just that there may be no disadvantage under the right circumstances.

It may be that the effect is very small, but if that is the case, then the energy consumption to be reduced by using the fluorescent bulbs must also be very small.

Also, there are countries where fossil fuels are cheap while electricity prduced from them is not - bad housekeeping to heat your home with light bulbs instead of turning up the heat on the oil heater you filled with cheap oil.

Yes, this occurred to me.

The thing I recall reading about electrical heating many many years ago was that it was "expensive". Whether that is still the case, and whether it is specific to certain countries/regions, I do not know.

Then of course, if you use the new lamps for a flashlight, the calculation is even more favourable: Buying a fifth of the batteries (=ineffecient, expensive, chemical electricity storing devices) surely is lighter on your pocket especially since flash lights aren't normally used to keep warm.

Yes, I definitely wouldn't propose that.

An artist had a lovely idea for this. When the EU banned 100 W light bulbs, he offered them as "heating elements; just put them into a socket usually used for lamps, and not only will they keep you warm, they will also produce a bright, warm, comfortable light". And the piece of art was, he was actually allowed to sell them as heating elements.

Heh heh, loopholes

So yeah, you could save a notch on your heating costs, under certain circumstances. Still, the 18 W replacementws are probably a good idea under most conditions.

Well, they'll be a good idea for sure here, since we air condition rather than heating.

I didn't see an 18W at the shop, I got a 20W that burns a bit brighter.

And I rode on a nearly empty double-decker bus to get to the shop.

[Enzo]

My understanding is that this “fire” can also be used for cooking. What technology! Exciting times ahead.

Me talk to Mog over in cave 14, and Mog say he thinks this "fire" can even be used to harden spear points. Me not sure, but Mog one smart cookie.


I think the light bulb is less efficient at heating than the power plant, so I don't think it is a wash there.


Recycling? I recall a long while back, I had gathered an entire pickup truck full of recycles and was at the center depositing it, when a lady drove up in her BMW, tossed three empty milk jugs in the bin, and drove off. Good to see we are all involved.

[Мастер]

I think the light bulb is less efficient at heating than the power plant, so I don't think it is a wash there.

This is what I’m stuck on - the light bulb produces heat and light. If it’s inefficient, where does the energy used go? It can’t just disappear. But I can’t figure out where it would go. Chemical energy? Potential energy? Kinetic energy? None of those seem to fit. Something else?

Might it produce non-visible electromagnetic radiation, that goes out the window (literally)?

[Arneb]

It is really just heat (so, kinetic energy). Remember the days when lampshades would catch fire because the came too close to the light bulb? I still have a hard time touching one of the new light bulbs even though they are just slightly warm to the touch, when touching an old 100 W thing could give you a burn in seconds.

[Enzo]

Most bulb inefficiencies go into heat. An old style bulb USED the heat to make light - it heated the filament enough to make it white hot LEDs and CFLs do not rely on heating anything to create light.


BAck when I lived in the country and raised chickens, I placed the aluminum water bowl over a light bulb. heat from the bulb was sufficient to prevent the water from freezing in winter. For that matter, when I was a child, ny dad had a piano in the basement, and he was concerned over humidity. He mounted a socket and had a small 15w bulb running full time in there to keep it dry.

[Мастер]

I think the light bulb is less efficient at heating than the power plant, so I don't think it is a wash there.

Most bulb inefficiencies go into heat.

It can't be inefficient at producing heat because it produces heat instead.

I can easily see how it is not efficient at producing light. The old-style bulbs - if you touched them, you'd burn your fingers. Because they produced heat. The amount of inefficiency was even printed on the packaging the bulbs came in - 100 watts for so many lumens from an old incandescent bulb, far fewer watts for about the same number of lumens from a new fluorescent bulb.

If you only want light, and heat is a waste product (or as is the case where I am, something undesired, that you have to expend energy to get rid of), then this is inefficiency. More electricity used to get the same amount of light, and maybe even still more electricity used to get rid of the unwanted heat.

But if heat is not a waste product, but something you actually want - then it's not an inefficiency. You are using the so-called "waste".

If a bulb is grotesquely inefficient at producing light, and produces a massive amount of heat instead, and the heat is something I actually want, so that I can turn my heating system down to a lower level, then I am using all of the light and heat the bulb is producing. Nothing is wasted.

If it is still inefficient, even when I use all of the light and all of the heat it produces, then the energy it is consuming must be converted into some form other than light and heat. If so, what is that other form?

[Мастер]

It is really just heat (so, kinetic energy). Remember the days when lampshades would catch fire because the came too close to the light bulb? I still have a hard time touching one of the new light bulbs even though they are just slightly warm to the touch, when touching an old 100 W thing could give you a burn in seconds.

I remember many many many long years ago, we had a table lamp that we had sitting on the floor instead. It was broken, if you knocked it on the side, the part holding the bulb would fall over sideways and touch the floor. Then you had to pick up that part and put it back in its place, so it would sit upright, as it was supposed to.

One day, it fell over, and was left unattended, and burned a hole through the carpet.

There were some unpleasant words about that.

[Arneb]

It can't be inefficient at producing heat because it produces heat instead.

I think that goes without saying. To call something efficient is to say it gives you something you want at a price you are willing to pay. There is no "efficiency" in any system without first specifiying what you want to get out of it. You could say that a Hummer is extremely efficient at releasing CO2 into the atmosphere because all you have to is drive a mile, and BANG, more than a pound of the stuff added to the atmosphere. That went ligtning fast, and all you had to was press down the accelerator.

Like you always say, what the sentence "XYZ is good for the economy" means depends sensitively on what your definitions of "good" and "the economy" are.

[Мастер]

It can't be inefficient at producing heat because it produces heat instead.

I think that goes without saying.

Well, I was told that the bulb is an inefficient way to produce heat, and most of the inefficiency goes towards producing heat . . .

[g-one]

Electric heat is 100% efficient. That would be like baseboard elements. If a different type of electric heater has a fan in there you would lose a bit.
Any (heating) inefficiency in an incandescent would be waste light.

Which brings me to a similar question I've pondered. Sound takes power to produce. The higher the SPL, the more power required. So those loud F1 V10 engines everyone loved must have lost extra horsepower for the louder sound production. I'm sure there's some pertinent trade-off somewhere.

[tubeswell]

It can't be inefficient at producing heat because it produces heat instead.

I think that goes without saying.

Well, I was told that the bulb is an inefficient way to produce heat, and most of the inefficiency goes towards producing heat . . .

It's light (not heat) that incandescent bulbs are inefficient at producing compared to other (lower powered) bulbs of the same luminosity.

[Enzo]

Bulbs are very inefficient at lighting. The inefficiency at light production mainly goes into heat. But I think they are also less efficient at heating their environment than the power plant. The primary purpose of the bulb is to make light and heat is a necessary but unwanted byproduct.

[Мастер]

Bulbs are very inefficient at lighting. The inefficiency at light production mainly goes into heat. But I think they are also less efficient at heating their environment than the power plant.

I can see two ways this could happen.

One is, energy is lost before it gets to the home. Maybe there is significant loss due to resistance in power lines, I don’t really know. If so, then natural gas may be more efficient, if there is less loss during delivery.

The other (and the one I’m having trouble with) is how the bulb itself could be inefficient. It produces light and heat. If you want both of those things, then they’re not waste, their desirable outputs from the bulb. But for the bulb to be inefficient at producing a combination of these two things, the energy consumed must be turned into some third form. And I can’t think what that would be. It isn’t accelerating rocks to high velocities. It isn’t pumping water uphill. It isn’t producing gasoline that can be burnt later. Where is the energy going, if the bulb itself is inefficient?

Inefficiency in delivery of energy to the home, that I can see. But if the inefficiency is occurring in the bulb itself, there must be a third type of energy output, since energy is conserved. Is there a third form produced? If so, what is it?

So I just wonder if those currently experiencing the Arctic winter, and looking at their old incandescent bulbs, thinking, maybe I should save some energy by replacing them, will really save anything. At least before spring, when it gets warm.

[Arneb]

The other (and the one I’m having trouble with) is how the bulb itself could be inefficient. It produces light and heat. If you want both of those things, then they’re not waste, their desirable outputs from the bulb. But for the bulb to be inefficient at producing a combination of these two things, the energy consumed must be turned into some third form. And I can’t think what that would be. It isn’t accelerating rocks to high velocities. It isn’t pumping water uphill. It isn’t producing gasoline that can be burnt later. Where is the energy going, if the bulb itself is inefficient?

Indeed, there is no third form. I think the solution is in saying, incendescent bulbs are inefficient for lighting, because they produce too much heat on the side. And they are inefficient for heating, because they produce too much light on the side:). Nobody doubts that you can heat a room with a string of 100 W light bulbs. But beside having to live with a brightly lit room (or having to shade the lamps, equivalent to using an air con if the heat is undiseired), there are issues with reliability, there are issues with comfort (convective vs. radiative heat transfer), there are, as you mentioned, issues with transport losses, and issues with the cost of electricity vs. the cost of a fossil fuel used for heating, and issues of praticability when you have to packe your living room with a string of sockets low on the ground. Those factors go into a "housekeeping" sense of "efficiency". Energetically, a light bulb is inefficient for the purpose of heating and of lighting, except when you want to get the precise proportion of light and heating they produce.

So I just wonder if those currently experiencing the Arctic winter, and looking at their old incandescent bulbs, thinking, maybe I should save some energy by replacing them, will really save anything. At least before spring, when it gets warm.

Our winter is rather sub-sub-sub-arctic these days. We'd gain nothing from keeping the 100 W bulbs because our lights sckets are just as dependent on the grid as the heat pump (which provides about 5 times as much heat our of moving heat up from down below as direct elctrical heating would provide) is.

[Мастер]

Energetically, a light bulb is inefficient for the purpose of heating and of lighting, except when you want to get the precise proportion of light and heating they produce.

Well, if you use them for light, and they generate some heat, but not all the heat you need - then there would be no loss.

We'd gain nothing from keeping the 100 W bulbs

I don’t think there is any question of gaining something; perhaps just failure to lose anything.

The picture I have is of Ivan in Murmansk scratching his head, wondering, I installed all these high efficiency light bulbs; why is my energy bill the same as before?

Might that happen?

[Arneb]

Energetically, a light bulb is inefficient for the purpose of heating and of lighting, except when you want to get the precise proportion of light and heating they produce.

Well, if you use them for light, and they generate some heat, but not all the heat you need - then there would be no loss.

We'd gain nothing from keeping the 100 W bulbs

I don’t think there is any question of gaining something; perhaps just failure to lose anything.

The picture I have is of Ivan in Murmansk scratching his head, wondering, I installed all these high efficiency light bulbs; why is my energy bill the same as before?

Might that happen?

The no-difference scenario would be hard to actually produce - First of all, Ivan would have to produce his heating electrically, and maybe that's not terrible likely. I think it's more likeley that he would still see his electricity bill go down substantially, and his coal/gas/oil bill rise only a notch, simply because electricity produced frrom fossils is still more expensive than nurning the fossils directly.

But even assuming electric heating, it would not permit for times when you have the lights on, but not the heating. It would require the leakage of heat from Ivan's shed to be very preidctable and constant. It would require tha the heat from the lighbulbs does not escape out of Ivan's shed faster than the heat produced by, say, a good oil-radiator (light bulbs produce more heat in the form of IR radiation than with convective heating. And they are usually above people's heads, not a good place to install a heater in). Etc. etc.

However, I can very wll imagine Ivan's energy bill not going down as much as the advertisements had promised. But when was that ever different?

[MM_Dandy]

From various sources (but especially this one) on the web, a 100-watt bulb of any type generates about 341 BTU per hour, and a 26-watt replacement (approx. the same lumens) LED would generate about 89 BTU/hour, a difference of 253 BTU/hour.

Here is a list of the energy content of common sources. Ignoring any inefficiencies and other factors, you'd have to burn this much fuel per hour per bulb to make up the difference (I encourage you to double-check my maths):
Heating Oil: slightly less than 1/4 fl oz
Kerosene: ~1/4 fl oz
Liquid Propane: slightly more than 1/3 fl oz.
Natural Gas: 1/4 cu ft (432 cu in) (7.07 liters)
Coal: a little more than 1/4 oz
Dry Wood: ~1/2 oz