Are CF bulbs really a good idea?

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I’ve been using compact flourescent lights in my home for a few years and feel like I’m ‘doing my part’ to help save the planet. My wife assures me that I’m being an exemplary ‘Treehugger’. I purchased these bulbs on my own without any inducement to do so other than curiosity. But I recently heard that some misguided do-gooders are trying to outlaw incandescent bulbs. Even though that might not affect me too much since I’m already ‘with the program’, so to speak, I’m not a big fan of government intervention, unless it’s for a really good cause and unless it can be proven to solve a problem without introducing some other unintended consequences.

Not everyone is ‘on board’ when it comes to CF bulbs. A friend had asked me whether CFs light bulbs really have much of an impact on global warming by reducing the amount of CO2 that our fossil fuel-powered electric plants spew into the atmosphere each year. He wondered whether anyone had taken into account the beneficial effect of the heat incandescent bulbs generate in the winter time that offsets the load on the residential furnace. I had to admit, I had never heard of anyone who had taken that into consideration. So I decided to do some calculations myself.

An incandescent bulb converts only about 2% of the input power in usable light. A CF bulb produces about 4 times as much usable light per watt than an incandescent light bulb. At this point, if I were on the usual trajectory of discussing energy savings, I’d be ready to start gushing about the number of tons of CO2 that could be avoided if everyone were all to switch to CF bulbs. But I’m not going to do that because talking about tons of CO2 doesn’t really tell anyone anything. Why even bring up the CO2 number at all? It really boils down to how much of a percentage impact you can have on a problem. Mixing pounds or tons of CO2 reduction when talking about energy efficiency is a complete non sequitur and does nothing to put energy savings in perspective. If I can tell you how much of a percentage savings you can expect with CF bulbs, then you can tell if it’s a big deal or a little deal and draw your own conclusions about its impact on CO2 reductions.

If an incandescent bulb is 2% efficient at converting electricity to light and a CF bulb takes about 25% of the energy to produce an equivalent amount of light, then it follows that it’s about 8% efficient. So, you might ask, where does all that other energy go that is not being converted into beautiful lumens of light? The answer is that it is converted into heat. Actually, even the lumens of light also end up as heat too, which means that after it has bounced around the room a few times, all the objects, including your retinas eventually turn those lumens into heat as well.

As you move away from the equator it’s necessary to use more interior lighting in the winter than in the summer due to the fact that the nights are longer in winter. If we need to use our lights longer, and all the energy used by the bulb eventually becomes heat, it begs the question, “Are these lights helping to offset the amount of work my furnace has to do?” For about 6 months out of the year my furnace runs at least a little bit each day, so yes, you can assume that the heat generated by my lights, and for that matter, my refrigerator, TV, computer, etc., all help to offset the amount of work that my furnace would otherwise have to do to keep my house at a comfortable temperature.

It would only be fair to acknowledge that in the summer, the opposite would be true, i.e., all my electrical loads counteract the work that my air conditioner needs to do during the time I’m running it.

But the winter months are when a typical house consumes most of its energy primarily for space heating needs. So, how much ‘help’ does my furnace get from my lighting, and how does it offset the cost of heat when compared with the cost of natural gas that handles the bulk of that task?

In a previous article I wrote for another website, I showed the effective cost of producing 1M BTUs using various fuels based on current prices and conversion efficiencies. There is a table in that article that shows that natural gas effectively costs about $14 per MBTUs based on a furnace with 85% efficiency. For a similar amount of energy from electric resistive heat, which is 100% efficient, the cost is about $26 per MBTUs assuming a $.10/kWh electricity cost.

A typical household in the U.S. uses electricity at the rate of 1 kW. This results in an average electric bill that is 720 kWh per month or 8760 kWh per year. You can multiply those numbers by $.10/kWh to figure the monthly and yearly average cost of electricity in the average U.S. household. Please note that U.S. kWh rate varies considerably by geographic area from as little as $.06/kWh to $.25/kWh with the average being around $.10. Prior to the widespread use of CFs, about 9% of residential electricity consumption was attributed to lighting according to the U.S. Department of Energy’s website. Since heating values are typically measured in BTUs (at least here in the U.S.) I will convert the electricity used for lighting into heat using the standard conversion factor of 3412 BTU/kWh. It gives a value that the lighting load in an average residence of about 7400 BTU/day. In the winter, we can assume this is higher, and in the summer, it would be lower due to the difference in the length of the days. I will use 10,000 BTU/day for winter months and 5,000 BTU/day in the summer for simplicity’s sake.

A typical household in the U.S. uses about 90 M BTU per year for space heating and most of it is consumed during 4 months in the winter. That would be a heating load of 750,000 BTU/day on average. This means that a typical furnace consumes about 75 times as much energy during the winter as all the lighting in a house. Heat generated by lighting will thus offset the furnace load during the winter months by about 1.3%.

In the summer, the heat load that lighting generates will need to be offset by the air conditioning, and thus will increase air conditioning cost, and using the numbers from the same DOE website shows that 16% of annual electricity consumption attributable to air conditioning. In the event that all 16% of the air conditioning bill was generated during 4 months in the summer then the monthly average consumption would be 350 kWh during those months. This corresponds to 12 kWh per day. Using a conservative SEER of 10 means 12 kWh translates to cooling of 120,000 BTU/day. (See my article on Heat Pumps for the definition of SEER and other efficiency ratings.) With the 5000 BTU/day of heat generated by lighting in the summer, the air conditioner has to work 4% harder to compensate for the heat generated by the lights.

So, what are savings associated with compact fluorescent lights? Assuming you can cut down on the thermal heat generated by 75% over incandescent lights, which, as I mentioned average about 9% of a typical electric bill, you should be able to save about $59/year in electricity if you could convert all your lights to CFs. This amount comes from a calculation of:

.75 x 8760 kWh/year x .09 x $.10/kWh = $59.13

You’d have to buy about 1% more natural gas to compensate for getting 75% less heat from CF lighting in the winter. This will cost an extra $12.60. (.75 x .013 x 90 MBTU x $14.00/MBTU)


In the summer, you’d get a 3% break on your air conditioning bill which, using $.10/kWh, would come out to $4.20 annually. (.75 x .04 x .16 x 8760 x $.10)

CF bulbs are more expensive to purchase than incandescent bulbs, about $1.50 vs. $.50 each for a 60W bulb. But they last about 8 times longer, so even with the higher purchase price, you will spend 63% less per bulb replacement cost overall. Again using the 9% of an electrical bill over a year, the lighting consumption comes out to an average of 788 kWh per year. That’s like having 1.5 60-watt incandescent bulbs burning all the time. If you did that, each light would need to be replaced about 8 times per year (assuming an 1100-hour life) for incandescent bulbs vs. 1.5 times per year with CF bulbs (assuming an 8800-hour life). So the bulb replacement cost savings are an additional $1.75/yr.

The calculation I used for that was:

8 incandescent bulbs x $.50/bulb – 1.5 CF bulbs x $1.50/bulb = $1.75

So lets add it all up:

$59.13 +$4.20 + $1.75 – $12.60 = $52.48 annual household savings to going to CFs

So it appears that the electricity savings + reduction in air conditioning + reduced in cost of replacement bulbs – loss of heating in winter still makes it more economical to use CFs over incandescent bulbs. It’s interesting to note that the savings in electricity is by far the dominant contributor to the savings calculation.

But in the grand scheme of things, a reduction of $52.48 in a combined heating + electricity bills of around $2100 annually is less than a 2.5% household energy savings and thus isn’t going to make a big dent in global warming or reduce our dependence on fossil fuels very much.

It would seem that passing a law to make incandescent bulbs illegal is just something to make people who are unable to do math feel good about themselves. Maybe they can express it in tons of CO2 savings and obfuscate its contribution even further. Let’s just call it what it is, a potential 2.5% energy savings which is not nearly enough incentive to pass a law when the simple economics should provide enough of incentive, not to mention cutting one’s bulb replacement workload down by 87%.

Now I know that some may want to take me to task for my criticizing CF bulbs for making minimal contributions to the goal of overall energy reduction, but I am a tired of people saying things like, “But if everyone just did a little, we’d save a lot“. No, we really wouldn’t. If all 100 million households in the U.S. save 2.5% of their electricity bill by switching to CFs, the overall savings are not 250,000,000%, as some math-challenged people may think, they are just 2.5%, overall, period. Savings like this would get eaten up in about 3 years with a population increase which is occurring at nearly 1% per year in the U.S..

I wish that everyone would just talk in terms of percentages when it comes to reducing energy consumption and not obfuscate the issue by introducing tons of CO2 emissions or some other unrelated metric into every energy discussion. One of my favorites is using an seemingly impressive expression such as ‘equivalent to taking 100,000 cars off the road’. Just to put that in perspective, there are 600 million motor vehicles in the world, so, although 100,000 sounds like an impressive number, it’s less than .01 percent of the total. Just in case there’s any doubt, I consider a .01 percent improvement to be a insignificant contribution that is hardly worth talking about. So I think we should stick to percentages when it comes to energy improvements.

To eliminate modern society’s dependence on fossil fuels, we will need to find ways to significantly reduce energy consumption as well as simultaneously figure out how to augment and eventually replace nearly all of our current energy production with renewable energy sources. I don’t think we can legislate a solution into existence by targeting small contributors like residential lighting. If we want to be a good “energy efficiency fascists” so as to modify people’s behavior with legislation, then we’ve should be attacking energy consumption on a larger scale while simultaneously replacing massive amounts of generating capacity with renewable sources. A 2.5% reduction that already has an economic incentive would be unlikely to benefit from further legislation to outlaw incandescent bulbs. Besides, there are some applications that incandescent bulbs can do where CF bulbs would not work well, such as lighting the inside of a refrigerator. CFs take about a minute to warm up and so a refrigerator is much better served with an incandescent bulb. It’s only on when the door is open, after all.

I guess I should also mention the controversy of the mercury in CF bulbs. Mercury has been used in fluorescent bulbs ever since they were invented in the 1930s, and no one gave it much thought. Commercial and industrial lighting applications converted over to fluorescent bulbs years ago and have had methods for their proper disposal going back decades. The disposal method for a burned out CF bulb is to put it in a sealed bag and bury it in a landfill so that it doesn’t end up in our water supply. One source of methyl-mercury that ends up in fish comes from burning coal, which goes into the atmosphere, comes down in rain, and can concentrate in fish. Since CF bulbs require less electricity, hence less coal is burned to generate electricity, the overall effect of the mercury contamination concern is reduced with CF bulbs, but this is often neglected because of the hysteria about what to do if a CF bulb breaks, a topic that has been answered by the EPA.

So in conclusion, I think that CFs are a good idea that need no further government legislation to get them to be more fully adopted. There’s speculation that they may even be replaced with LED technology in the future which will eliminate the mercury concern, but I think that may take a while. I’ve been using a white LED for reading lamp and it is 1000 times more efficient than using a 60W incandescent bulb, but that’s mostly due to a behavioral change, since I’m lighting up just the reading material, not the whole room with the reading light. Those are the types of changes it will take to get off the fossil fuel gravy train. In reality, the number of lumens per watt for a white LED are only about 50% more efficient than CFs today. Even with the further LED technology improvements in the number of lumens per watt, it won’t be quite the 4x jump in efficiency that we made by going from incandescent bulbs to CFs, but perhaps another 2X improvement over CFs, which would be worth switching if they can get the multi-watt LED lamp costs to be competitive with CF bulbs. Today, for limited power requirements such as flashlights, the switch is already happening which is why you are seeing more and more flashlights switching to LED technology.

Heat Pumps and Net Zero Energy homes

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My friend Jack asked me recently about geothermal heat pumps. I have been looking into heat pump technology for a while and wanted to write about it, so I gave him a longer-than-usual reply and figured I’d put some of what I wrote in my blog for anyone else who was curious about ground source heat pumps and net zero homes in general.

Heat pumps are like air conditioners running in reverse. You can use a heat pump to either heat or cool a building by reversing the flow of its refrigerant. Just as air conditioners become less efficient when the outside temperature gets too high, heat pumps get less efficient when the outside temperature gets too low (like around 30F). Of course, this is the worst time for a heating system to start losing its efficiency, that is, as the outdoor temperature gets colder, because it’s precisely when the maximum output from it is required. This is one of the reasons heat pumps have not been as popular in colder climates as they are in mild climates.

The benefit of adding a geothermal source to a heat pump is that the heat exchange loop stays at a consistent temperature. This allows the heat pump to maintain its efficiency because the earth below the frost line at most latitudes in the lower 48 states stays at a consistent 50-60 degrees F year round. This constant source of temperature allows heat pumps to maintain a high ‘coefficient of performance’ (COP). The COP is similar in concept to an air conditioner’s SEER (Seasonal Energy Efficiency Ratio). Basically, the COP is a ratio of watts of electricity input to watts of heat output you get. A typical heat pump has a COP of around 3 if the difference between the indoor and outdoor temperatures is within about 40 degrees F. The less the temperature difference, the higher the COP and conversely, the larger the temperature difference, the lower the COP. A COP of 3 is like getting 300% efficiency compared with simple electric resistive heat which is 100% efficient. A 100% efficient heater has a COP of 1. However, when the outdoor temperature approaches freezing, a heat pump’s COP can drop down below 1, at which time a resistive backup heater takes over. The primary drawback of an air source heat pump is that just when you need heat the most, a heat pump starts to get much more expensive to operate due to the reduction in its COP. For geothermal (i.e., ground source) systems, the COP is closer to 3.5 all the time and so it doesn’t suffer from the problem with air source heat pumps that vary with outdoor temperature.

An air conditioner’s efficiency is measured by its SEER which is basically the COP averaged over a range of typical outdoor temperatures and multiplied by 3.413. Typical values for an air conditioner’s SEER are around 10-15 which corresponds to an COP range of 2.9 – 4.4 . It’s been improving over the past few years, mostly due to government mandates. In Japan, they are now producing heat pumps with COPs as high as 6.

To add a geothermal heat sink to a heat pump system, you need to bury the heat exchanger loop below the frost line. This can be done using a loop in a vertical bore hole or in a horizontal trench. In general, a ground source heat exchange loop for a typical house would be between 1500 to 2500 feet long depending on the size of the system, and buried at least 6′ deep. The costs to install the heat exchange loop are similar to those of drilling a well in the case of a vertical system, or digging a 6′ deep trench several hundred feet long and two feet wide. So the installation of the heat exchange loop can get quite expensive. If the loop is arranged in a coil in a trench, you need about 1 foot of trench length per every 4 feet of loop. As you can imagine, this would not be easy to do unless it’s done during the construction of the house and prior to any landscaping. Also, if anything goes wrong with the loop such as having a leak, it would be very expensive to isolate and fix the problem once it’s buried.

If heat pumps are 300% efficient, why doesn’t everyone use them? After all, a gas furnace is only abut 80% efficient. One reason is that generating electricity from coal, gas, or nuclear power is only about 30-40% efficient. As much as 2/3 of the thermal energy created at an electric power plant becomes wasted heat. So the overall savings due to the multiplicative effect of the heat pump are offset by the losses of converting the fuel to electricity back at the power plant, not to mention the losses of delivering energy over the electrical grid. That’s part of the reason that electricity tends to cost about 3 times as much per unit of energy as buying natural gas and burning it in a furnace to heat your house. The capital and installation costs of a geothermal heat pump system are also significantly more than a gas furnace (about $25K vs. $3K).

I currently spend about $800 per year to heat my home with natural gas and a similar amount on electricity. I figure if I were to use electricity and a geothermal heat pump for heat, it would cost about the same as what I currently pay for natural gas, but I’d have an extra $22K in capital cost for the heat pump over the cost of a gas furnace. Now, if I had a total solar electric home then it would make sense to consider a heat pump, but to do that, I’d need to have about 12 kW of solar panels installed on my roof (at a cost of $86K), based on my annual gas and electric consumption. Even with generous solar rebates (currently $4.50/W by my utility company, up to $45K) and the new solar tax credit just passed by the U.S. Congress (up to 30% of the net solar system cost) that could take my cost of the solar system down to around $29K. But it still would be hard to justify because of the additional capital outlay for the heat pump, bringing the system cost up to $54K.

To get to net zero energy with my existing home using PV solar and a ground source heat pump, it would take about $111K in capital expenditures of which $57K could be foisted off on to my fellow taxpayers and utility customers. But that’s still too expensive to justify it based on its economic return. It would take about $54K in personal expenditures to save $1600/year in utility bills. Ignoring the cost of financing a $54K expenditure, the amortization of the system would be $2700 per year assuming it needed to be replaced in 20 years. But if energy prices doubled, which is certainly possible, it would begin to look much more attractive. They’d need to quadruple for it to be attractive without subsidies.

Energy efficiency initiatives don’t get a lot of attention because most of them have negative economic returns. This is usually due to the low cost of energy in the U.S. which is about half of what Europeans pay due to higher energy taxes. However, if you use energy efficiency as a way to reduce capital costs of a renewable energy system, the picture is quite different, primarily because renewable energy capital expenses are so high. My electricity and heating bills are currently on par with the U.S. average. If I could figure out how to reduce them by 50%, it would allow me to reduce the size of a renewable energy system proportionally to be half the cost. This is usually when efficiency becomes a much more attractive proposition. Getting by with a 6 KW solar system for all our electric and heating needs would cut the previously mentioned $86K pre-rebate cost in half.

If energy prices go up significantly, and there’s good reason to believe they will as oil and gas production peak, you’ll likely see a lot more uptake in the technologies that help create net zero energy homes.

Channeling Steve Fossett

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Because I’m a pilot, I often get asked to speculate on the causes of plane crashes where there’s not enough evidence to know for sure what really happened. Such is the case with Steve Fossett where I get periodic requests to give my opinion about what happened in his mysterious disappearance in a borrowed airplane. Just for those who haven’t been paying attention, Steve Fossett was a wealthy adventurer who set numerous aviation records including traveling around the world solo in a balloon as well as flying an airplane solo without refueling around the world. He took off on a sightseeing flight from Barron Hilton’s Ranch in Nevada last September and was never seen again. Just a few weeks ago, more than a year after he disappeared, some of his personal effects were found by a hiker about 80 miles from the ranch where he had departed. Shortly after that, the crash site was discovered in the Sierra Nevada mountains.

A recent Avweb newsletter linked a set of pictures on Flickr posted by one of the SAR team members who helped clean up Steve Fossett’s crash site. There are about 10 pictures in the middle that show parts of the plane that start right around the one with the newspaper clipping image.

What I found interesting was the caption on the photo 43 that mentioned that the plane impacted the ground climbing at about a 10 degree angle on a slope that was at a 20 degree angle leading me to think that Fossett may have had a problem with the airplane and so he tried to land by attempting to climb uphill and get the aircraft to stall right around the time it contacted the ground. A ‘roll out’, if you want to call it that, on a 20 degree slope uphill would be pretty short. However, there were a lot of rocks and trees and so it appears that the plane broke apart on landing and then was consumed by fire. To make that maneuver work, you would have to do it ‘just right’.

At an EAA chapter meeting last night, someone mentioned that Bob Hoover performed this maneuver where he knew he was going to crash and so he did it going up hill and he and his passengers walked away from it. Here’s that story, excerpted from my (autographed) copy of Bob Hoover’s autobiographical book “Forever Flying”.


One of the more frightening experiences I’ve had occurred after an air show in 1989 at San Diego. It was held at Brown Field, which is located just a few miles from the Mexican border.

I had completed my performances in the P-51 and the Shrike Commander. I told the line boy who drove the fuel truck to service the Shrike quickly so I could leave right after the show was completed.

The young man asked how much fuel I needed. I told him I wanted precisely sixty gallons. I added, “That’s hundred octane.”

After my performance, I went to the manager’s office, where he received a phone call from the same young man. The manager told me the boy wanted to know if 100 LL (low lead) was all right for my airplane. I told him it was. He relayed the message.

Normally I like to be present when the airplane is being serviced, but I was held up when I came out of the airport manager’s office. By the time I got to the airplane, the truck was pulling away. I said, “Fueling done?” The boy replied, “Yes, sir. It was sixty gallons precisely.”

When I taxied out, probably at least a hundred airplanes were waiting for takeoff. But as soon as I called in, the tower said, “Mr. Hoover, we want you to taxi to the head of the line.”

I did not like to leapfrog ahead of other pilots. However, since time was scarce that day for me and my two passengers, I accepted the tower’s kind offer.

The takeoff was smooth. Everything was normal and checked out perfectly. All of a sudden, at about three hundred feet, I realized I didn’t have any power in the Shrike. I started losing airspeed.

I dumped the nose, but I couldn’t understand what was happening. Everything checked out. The manifold pressure was right where it was supposed to be. The rpm were at the right setting. The fuel pressure and oil pressure were in good shape. Even though the gauges indicated that nothing was wrong, I knew something was. I started looking for a place to land. That would not be easy.

Brown Field is located on a plateau. To the north where I was headed, there were deep ravines. I could try to recover and head back to the airport, but I knew I wouldn’t make it.

My two passengers tried to remain calm, but they were obviously frightened. Both thought we were going to crash and die. “Mr. Hoover,” they asked more than once, “are we going to make it?” I assured them we would.

As I have mentioned before, each time potential disaster strikes, I rely on my experience of anticipating trouble to help me out. I had flown the P-51 cross-country for many years. I’d often considered what might happen if I had to put it down over the Rockies.

Recalling those thoughts, I dumped the nose of the Shrike. I kept my best glide speed until I reached the very end of the ravine. Landing in the bottom of the canyon meant no survival. Our only chance was to pull up and land on the side of the ravine.

As my airspeed bled off, I dropped the landing gear and flaps. I wanted to be at a minimum forward speed on impact. The landing gear would cushion the impact along with the tires and struts before the impact hit us square on.

I was down in a V-shaped ravine. A thousand feet wide at the top, it narrowed down to nothing at the bottom. I went right to the bottom to maintain the best glide speed. I then pulled the plane up and landed into the side of the ravine. I didn’t travel very far at all before I hit a rock pile that caved in the nose. The instrument panel was torn out of its mounts and dropped down on my shins.

Neither of my passengers was hurt, but there was one fatality. We ran over a rattlesnake with the belly of the airplane when the gear tore out from under it.

We sat there awaiting rescue. I considered what had caused the lack of power. Only one thing was possible: the plane had been serviced with jet fuel instead of gasoline.

To confirm my suspicions, I went around to the side of the airplane and opened the drain valve. I leaned down and took a whiff. Sure enough, it was jet fuel.
My mind flashed at once to the young man I had asked to service the airplane. He must have known by then what had happened as I had informed the tower of the emergency.

Within minutes, rescue helicopters were on the scene. My passengers and I climbed up the ravine and were transported back to Brown Field.

After making sure the Shrike would be protected from theft, I asked, “Where is the line boy who serviced the plane?”

Everyone seemed reluctant to tell me, apparently afraid that I wanted to chew him out or be unkind to him. Finally, someone said, “He’s outside.”

An article in the Fullerton (Calif.) News-Tribune the next day quoted me regarding what happened next:

When I got back to the field, I saw the boy standing by the fence with tears in his eyes.

I went over and put my arm around him and said, “There isn’t a man alive who hasn’t made a mistake. But I’m positive you’ll never make this mistake again. That’s why I want to make sure that you’re the only one to refuel my plane tomorrow. I won’t let anyone else on the field touch it.”

Just as I said, I had the boy refuel my P-51 for the final two days of the air show. Needless to say, there were no further incidents.
Shortly after that, I received a wonderful letter from a doctor in Palos Verdes named William Snow.

He wrote:
I wanted you to know that I was quite touched by the apparent casual way in which you trea
ted your unfortunate incident. Thank goodness it was just that and nothing more! However, what really impressed me was your genuine concern for the young man who had serviced your plane.

It is rare to find a person who has just experienced such a close brush with death and yet feels such compassion for his fellow man. God surely must be your copilot!


I could have just cut off that excerpt at the part where Hoover crashed, but I was so impressed by how he treated the line boy, that I’m sure you all wanted to hear how it ended.

Another interesting photo is of the Google Earth map below that shows where the shirt and ID were found. They appear to be about .7 miles from the wreckage. I can only assume that those items may have gotten carried away by animals.

The NTSB report has very few details so far, but I’m sure that it will accumulate more details about the crash as they start to examine the wreckage.

We may never know what happened, but it’s obvious a fire ensued after the crash. Had the fire started while he was flying? If so, was he attempting to get the airplane on the ground as quickly as possible using the famed Hoover maneuver? We may never know, but I am eager to see what the NTSB has to say about it after they spend some time examining the wreckage.