More Heat than Light

Counterintuitively, your home electric heater likely puts out at least twice the heat that you put in as electricity. Most modern heaters are heat pumps, which extract heat from surroundings. See the Wikipedia article on heat pumps for info.

Counterintuitively, your home electric heater likely puts out at least twice the heat that you put in as electricity. Most modern heaters are heat pumps, which extract heat from surroundings. See the Wikipedia article on heat pumps for info.

You are more or less correct — because of the conservation of energy, that which is not light becomes heat, full stop.

As for the heat pump comment, actually, only some modern electrically heated homes use heat pumps.

You are more or less correct — because of the conservation of energy, that which is not light becomes heat, full stop.

As for the heat pump comment, actually, only some modern electrically heated homes use heat pumps.

It’s been a while since I took physics, but I’m pretty sure that the conservation of energy suggests this is a non-sensical question. If all the energy is being converted into either heat or light, and both heat and light are desired, then it’s incoherent to talk about the heat-producing efficiency of the bulb, since there’s nowhere else for the energy to go.

Tim, go back and retake your high school physics. Certainly, if everything were the same efficiency, you would be right–but not everything is the same efficiency. For example, in electric circuits there is transmission loss, which varies by distance from the power generating source. While there is some energy used to convey natural gas to your home/apartment, natural gas is still more efficient. Now, factor in the fact that your electricity is probably generated from coal, and the reduction in electricity use ends up being a net reduction in carbon emissions.

But still, being quite concerned with the quality of the light generated, I confess I really can’t stand the light from the CFL’s so I generally use incandescents in places where the quality of light is important, and CFL’s where it isn’t as important, or where I can mix the light with either daylight or incandescent light. Just a little incandescent goes a long way. So about 60 – 70% of my house uses CFL.

That being said, I think there should some exceptions–for example if I buy all of my power from wind sources (as I do)–I don’t understand what the problem should be. I am only using green power….

It’s been a while since I took physics, but I’m pretty sure that the conservation of energy suggests this is a non-sensical question. If all the energy is being converted into either heat or light, and both heat and light are desired, then it’s incoherent to talk about the heat-producing efficiency of the bulb, since there’s nowhere else for the energy to go.

Tim, go back and retake your high school physics. Certainly, if everything were the same efficiency, you would be right–but not everything is the same efficiency. For example, in electric circuits there is transmission loss, which varies by distance from the power generating source. While there is some energy used to convey natural gas to your home/apartment, natural gas is still more efficient. Now, factor in the fact that your electricity is probably generated from coal, and the reduction in electricity use ends up being a net reduction in carbon emissions.

But still, being quite concerned with the quality of the light generated, I confess I really can’t stand the light from the CFL’s so I generally use incandescents in places where the quality of light is important, and CFL’s where it isn’t as important, or where I can mix the light with either daylight or incandescent light. Just a little incandescent goes a long way. So about 60 – 70% of my house uses CFL.

That being said, I think there should some exceptions–for example if I buy all of my power from wind sources (as I do)–I don’t understand what the problem should be. I am only using green power….

EF, that’s a good point. My argument would work if we were comparing an electric lightbulb to a space heater, since the transmission loss would be the same, but if we’re comparing electric to gas heat, then then as you say there could be power losses before the power gets to the house.

EF, that’s a good point. My argument would work if we were comparing an electric lightbulb to a space heater, since the transmission loss would be the same, but if we’re comparing electric to gas heat, then then as you say there could be power losses before the power gets to the house.

I long ago got out of the rat-race of arguing “efficiency”.

It simply is not possible with some words to define what in the local context is meant by “efficiency”.

Let me show an example that does not have the current emotional hangups (CFL’s are bad because they can’t be used in closed fixtures, they contain mercury, and they don’t produce enough light, end of that discussion.)

In an earlier life I was involved in writing computer programs, where the efficiency argument would come up over using so-called low-level codes to get the maximum amount of work out of a machine versus using high-level codes to get the maximum amount of work out of the programmers.

Which is more efficient? It depends.

I long ago got out of the rat-race of arguing “efficiency”.

It simply is not possible with some words to define what in the local context is meant by “efficiency”.

Let me show an example that does not have the current emotional hangups (CFL’s are bad because they can’t be used in closed fixtures, they contain mercury, and they don’t produce enough light, end of that discussion.)

In an earlier life I was involved in writing computer programs, where the efficiency argument would come up over using so-called low-level codes to get the maximum amount of work out of a machine versus using high-level codes to get the maximum amount of work out of the programmers.

Which is more efficient? It depends.

It simply is not possible with some words to define what in the local context is meant by “efficiency”.

Larry: you are right that we do have to carefully define what we mean be any efficiency metric.

My assumptions were, given the current concerns about global warming that the measure would be: unit of light produced vs. carbon output created to obtain. I think that’s a reasonable metric.

Note: the issue about mercury in this lights is a very real one, and that’s why the movement to cleaner energy is so important: if we got all our energy from wind/solar/tidal/geothermal we wouldn’t have to even have this discussion. Such a move will solve many of our problems. Don’t even get me started about the cost of a War in the Middle East which, unless you are living in an alternate universe, is all about energy supplies.

It simply is not possible with some words to define what in the local context is meant by “efficiency”.

Larry: you are right that we do have to carefully define what we mean be any efficiency metric.

My assumptions were, given the current concerns about global warming that the measure would be: unit of light produced vs. carbon output created to obtain. I think that’s a reasonable metric.

Note: the issue about mercury in this lights is a very real one, and that’s why the movement to cleaner energy is so important: if we got all our energy from wind/solar/tidal/geothermal we wouldn’t have to even have this discussion. Such a move will solve many of our problems. Don’t even get me started about the cost of a War in the Middle East which, unless you are living in an alternate universe, is all about energy supplies.

My argument would work if we were comparing an electric lightbulb to a space heater, since the transmission loss would be the same, but if we’re comparing electric to gas heat, then then as you say there could be power losses before the power gets to the house.

Except Tim remember two other things, one small one big:

You are thinking about heating season. In the cooling season, when the incandescents are running hot, not only are you spending more energy to generate your lighting, you are also adding load to your air conditioning.

You might be surprised to know that, for many types of buildings (e.g., Hospitals, assembly spaces, or even office buildings that have a lot of glazing and are loaded with computers) most of the year, even well into the winter, the load on the mechanical systems is cooling. This is because of the heat generated by the occupants and all of the equipment. So most of the time, you’d have incandescents generating heat that you then turn around and pay to cool.

My argument would work if we were comparing an electric lightbulb to a space heater, since the transmission loss would be the same, but if we’re comparing electric to gas heat, then then as you say there could be power losses before the power gets to the house.

Except Tim remember two other things, one small one big:

You are thinking about heating season. In the cooling season, when the incandescents are running hot, not only are you spending more energy to generate your lighting, you are also adding load to your air conditioning.

You might be surprised to know that, for many types of buildings (e.g., Hospitals, assembly spaces, or even office buildings that have a lot of glazing and are loaded with computers) most of the year, even well into the winter, the load on the mechanical systems is cooling. This is because of the heat generated by the occupants and all of the equipment. So most of the time, you’d have incandescents generating heat that you then turn around and pay to cool.

Yeah, that was actually the premise of the original comment at Yglesias’s site: that light bulbs weren’t inefficient in the winter when the heaters were on. Obviously in the summer this is all a moot point since power is being used to pump the heat out of the building.

Yeah, that was actually the premise of the original comment at Yglesias’s site: that light bulbs weren’t inefficient in the winter when the heaters were on. Obviously in the summer this is all a moot point since power is being used to pump the heat out of the building.

“The right way to deal with the problem is to ensure that the electricity is being priced appropriately (perhaps increasing taxes on generators if there’s evidence that they’re imposing uncompensated environmental harms) and then let consumers decide for themselves how much energy they want to ‘waste.’”

The “environmental harm” is the reason for the legislation in the first place. The problem is that this harm is unknowable, despite the “confidence” of the IPCC.

Predictions about climate are based on computer models. These models are very complex, because there are several very important factors which can raise or lower temperature. Look on page 4 of the 2007 IPCC Summary For Policymakers. Solar irradiance is a factor. The level of scientific understanding of this factor is “low.” Aerosols are a factor (a man-made cooling factor). The level of scientific understanding of the direct effects of aerosols is “medium to low” and understanding of the indirect effects (cloud albedo) is “low.” Humans have also changed the earth’s surface albedo through changes in land use, and this is a cooling factor, but again the scientific understanding of this factor is “medium to low.” The only climate factors for which the IPCC claims a “high” level of scientific understanding is greenhouse gases.

Logically, if climate depends on multiple factors, many or most of which are not solidly understood, it is foolish to think one can predict the future accurately. Therefore it is impossible to even begin to accurately assess any “environmental harm” in the form of global warming for the use of electric light bulbs, automobiles, or any other factor. Whatever certainty one may have or claim about the effects of greenhouse gases, it will be overwhelmed by the uncertainty of factors we don’t understand (albedo, aerosols) or can’t control (solar irradiance).

Long story short — the question can’t even be answered, let alone a price attached to the light bulb for its effect on the environment. For sixty years, solar activity has been exceptionally high. If the sun’s output weakens, as can be expected according to its cycles, we might be contributing to global cooling by using flourescents exclusively. Still, the net effect would be impossible to assess because of the uncertainties in other factors which must be plugged in to any climate model. At some point we might need more greenhouse warming to offset a new mini-ice age.

Of course, this is what Schwartz, Charlson, and Rodhe were saying (re uncertainty) in July 2007 on nature.com.

“The right way to deal with the problem is to ensure that the electricity is being priced appropriately (perhaps increasing taxes on generators if there’s evidence that they’re imposing uncompensated environmental harms) and then let consumers decide for themselves how much energy they want to ‘waste.’”

The “environmental harm” is the reason for the legislation in the first place. The problem is that this harm is unknowable, despite the “confidence” of the IPCC.

Predictions about climate are based on computer models. These models are very complex, because there are several very important factors which can raise or lower temperature. Look on page 4 of the 2007 IPCC Summary For Policymakers. Solar irradiance is a factor. The level of scientific understanding of this factor is “low.” Aerosols are a factor (a man-made cooling factor). The level of scientific understanding of the direct effects of aerosols is “medium to low” and understanding of the indirect effects (cloud albedo) is “low.” Humans have also changed the earth’s surface albedo through changes in land use, and this is a cooling factor, but again the scientific understanding of this factor is “medium to low.” The only climate factors for which the IPCC claims a “high” level of scientific understanding is greenhouse gases.

Logically, if climate depends on multiple factors, many or most of which are not solidly understood, it is foolish to think one can predict the future accurately. Therefore it is impossible to even begin to accurately assess any “environmental harm” in the form of global warming for the use of electric light bulbs, automobiles, or any other factor. Whatever certainty one may have or claim about the effects of greenhouse gases, it will be overwhelmed by the uncertainty of factors we don’t understand (albedo, aerosols) or can’t control (solar irradiance).

Long story short — the question can’t even be answered, let alone a price attached to the light bulb for its effect on the environment. For sixty years, solar activity has been exceptionally high. If the sun’s output weakens, as can be expected according to its cycles, we might be contributing to global cooling by using flourescents exclusively. Still, the net effect would be impossible to assess because of the uncertainties in other factors which must be plugged in to any climate model. At some point we might need more greenhouse warming to offset a new mini-ice age.

Of course, this is what Schwartz, Charlson, and Rodhe were saying (re uncertainty) in July 2007 on nature.com.