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Home > Resource Conservation > Electricity > Light bulbs

Resource Conservation: Electricity: Light Bulbs

light bulb graphic
     Lighting can be 10% to 25% of your power bill. Businesses tend to have a higher percentage than residential lighting. If you can cut your power use in half for lighting that is a reduction of 5% to 12% off your power bill. This may not sound like much but this could translate into hundreds or thousands of dollars a year. Visit the Greencompletely.com Store to see some light bulbs that are available.


Incandescent CFL Bulbs LED Bulbs Other Bulbs Lighting Facts Videos

Incandescent Bulbs


     A simple design that has not changed much in the last 100 years. It has few parts; a glass bulb, metal strips, Tungsten filament and some metal to make the base. Electricity passes through the Tungsten until it heats enough to produce light. 95% of the electricity going into the bulb is wasted in the form of heat and 5% is the light that we see.
     Since this type of bulb has been around the longest, most bulb fixtures are built to have these types of bulbs in them. Therefore, much of the newer (CFL, LED, etc) bulbs are built to go into these sockets.
      These bulbs have many uses and colors. Some uses are: flood light, spot light, 3-way, dimmable, and much more.  Of course, their CRI is about 100 for all types.
    These bulbs are very easy and cheap to produce. This is one reason why they are so inexpensive. They have a relatively short life expectancy (about 1,000 hours) so for longer use lighting jobs (24 or 12 hour lights) you may need to replace them every month or two.
     Many great strides have been made to make these bulbs last longer but they still will not last as long as some of the newer light types.

Energy Efficient:

     There is a good reason why the rest of the light bulb industry compares itself to incandescent lights. They are not as efficient as their counter parts (CFL, LED and others).  95% off the power used by an incandescent light leaves the bulb in the form of heat. The rest is light.
    One could argue, since these bulbs tend to be lighter than the other bulb
types, they will burn less fuel than other bulbs when transporting them. One could also argue that since incandescent bulbs mainly put out heat they could be used as heaters. This would require many lights to heat a small apartment and would not be as efficient as even buying an electric heater.  


Installation is not very complicated. as described above most all fixtures are made for incandescent bulbs. Some sockets are the E-series type some are bayonet but it is usually not problem to fit your bulb into a socket.
    A bigger problem is some of the steps taken by law makers to even buy these type of bulbs. This type of bulb is getting banned across the country, therefore, you may not even be able to get this type of bulb to install.
    From an expense point of view, these bulbs are very cheap. For normal bulbs you would pay $0.50 to $1.00. Some of the other types of bulb may be $3-$10 depending on the application. Some of the other applications are 3-way, flood, spot, PAR, candelabra and so on.


     Disposal of the light bulb itself is easy. The bulb is a simple construct; glass, some metal, a Tungsten filament. This could go to the land fill or if you had enough you could possibly recycle the components.
     The bulb comes to the store in corrugated boxes and there are small corrugated boxes that contain 2-4 bulbs. Therefore the waste generated from the packaging of the bulbs is reasonably done. However, you are throwing away about 8-10 incandescent bulb for each CFL you throw away and 30-40 incandescent bulbs for every LED you throw away.
     We would like to spend a little time talking about the electrical waste these bulbs cost. Since, these bulbs are much less efficient than other bulbs they put a higher burden on the power plants. If they use power generated by a coal plant then they create more pollution than other bulbs not pulling as much power. One of the toxic substances is Mercury and an incandescent bulb will create more Mercury waste than a CFL bulb. 

Our Picks:

     Believe it or not, you are visiting a green web site that actually recommends some incandescent bulbs. If you are looking to have only one type of bulb in your house or business then incandescent should not be used. However, if you are looking for saddle points of payoff we would recommend incandescent for a small portion of lighting.
      We at Greencompletely.com have another classification of light bulbs, it is an "Hour" classification. This is a classification of use of the bulb (or fixture). A 24hour light is one that needs to be on 24 hours a day 7 days a week. A 12hour light has to be on for an average of 12 hours a day (outdoor lights) and so on.
    Without a doubt your 24hour and 12hour lights should be LED or CFL. Your 10hour, 8hour and 6hour lights should probably be CFL or LED. However when we get into your 1hour down to your 0.1hour lights you may want to look at incandescent lights.  0.1 hour lights might be the lights in your spare bed room, your laundry room, maybe your closet or supply closet.
     For these lighting situations an incandescent bulb will last for years and the return on investment for another type of bulb will occur in 50 years or longer.
     We do not sell incandescent bulbs in our stores, we feel that they can be found anywhere.

CFL  Bulbs


     Several decades ago a new way was figured out to have more efficiently light our factories and businesses. This technology is called fluorescent lighting. At first it was a little weird looking. Fixtures were long and had a long (8') tube in them that was lighted. As funny as it looked it provided the same amount of light for about half the power. A new light fixture had to be created to fit the tubes and accommodate a ballast.
     Then a few decades ago ushered in the development of this same technology but in a smaller form. They miniaturized the ballast, made the tube smaller and curled it up. This is what we call a Compact Fluorescent Light (CFL) bulb. This was a design to allow CFL bulbs to fit into regular incandescent light sockets but last 8-10 times longer and consume about 1/4 the power. 
    Back then the CFL bulbs were a little temperamental and could only be used for one purpose, full on/full off. Therefore, dimming, 3-way and a few other applications were not possible. Over the last 30 years these bulbs have been refined to fill many other applications and be more robust in their operation. There are more designs, colors and applications then before. Generally, their CRI will be between 65 and 80.
     Looking at all considerations these are a reasonable alternative to incandescent bulbs. For some applications they can be a better choice than LED or most other bulb types. Below we weigh your options and look at the facts to help you make the right buying decision for you.

Energy Efficient:

    Is a CFL efficient? If you are comparing them to incandescent the answer is yes. A CFL tends to use 1/4 the power and have a life expectancy about 8-10 times longer than an incandescent bulb. However, in these same terms, an LED tends to use 1/2 the power and last 2-5 times longer than a CFL. The average life expectancy of an ENERGYSTAR approved CFL is 10,000 hours and a 100 watt equivalent (compared to incandescent) is about 23 to 25 watts.
     We would like to take the discussion a little farther by looking at the manufacture. An CFL bulb is made up of a lot more components than an incandescent. This means that there is a lot more energy expended to create a CFL vs. Incandescent. However, this amount of energy does not compare to making 10 incandescent light bulbs (the life of a CFL). 
    Even though CFL's are not as efficient as LED's they can provide a massive efficiency and price advantage over LED's  and incandescent bulbs for the right applications. Here we look at the 1hour to 6hour light bulb range. Depending on how much your power costs are and how much you pay for CFL bulb your return on investment may be much shorter for CFL's over LED and incandescent bulbs. This you could test in the calculator below.
     When making this kind of calculation bear in mind that you have shipping costs, cost of bulb, power costs and maybe labor costs (to replace bulbs).
     To learn more about efficiency standards required for CFL's to get ENERGYSTAR approval click here.
    For more information about agencies that create standards click here.


     Some CFL bulbs just twist into a normal socket and some don't. One of the main ways to make a CFL is that it screws into a normal socket. As mentioned in the above sections, a CFL has a mini-ballast. Some light fixtures today have the mini-ballast built into them. Then it is a matter of plugging in a CFL bulb into them. This assumes that the mini ballast will have a longer life expectancy than bulb itself.
     Some of the newer bulbs are a 2 pin configuration, some are a 4 pin and some have other amounts of pins. Some have a "GU" configuration (most common GU24). This is also called a "Twist and Lock" bulb.
    It appears the fixtures/bulbs were redesigned like this to help save you money. CFL's tend to be more expensive with a bulb and ballast built together. In this configuration, all you need to do is buy a new bulb when the old bulb burns out.
     This does a few things. It saves you money and it saves landfill/recycling volume.  It also has the tendency for the manufacturer to build a higher quality mini-ballast that can last a long time.
     The cost of the mini-ballast and bulb may cost a little more when initially bought separately, but from then on you will save when buying just bulbs.


     When looking at buying CFL's, you must also consider where to throw them "away" when they are at the end of their life cycle.
     If you are replacing incandescent or LED you can probably either throw them into the landfill or recycle them. CFL's are different. However, let's look at one thing at a time.
     Packaging for CFL's are sometimes in flashy plastic boxes or outer wrappings. This plastic is sometimes the recyclable type and sometimes not. It is counter productive to buy a product that has more initial waste than the product itself.
ballast of CFL     The bulb itself contains a mini-ballast. This is a small printed circuit with electrical components. Some of the components may contain some toxic materials but in general not too much. The outer housing of the mini-ballast is usually made out of  non-recyclable plastic.
    The tube that the light comes out of in a CFL contains Mercury. Not very much but the light won't work without it. This is true for all fluorescent lighting. In order for a CFL to be ENERGYSTAR approved it must have less than 5 mg (1/10,000 of an ounce) of Mercury in the bulb.  
      There are some prototype and production CFL bulbs that actually contain 1 mg of Mercury. This type may take a little longer to come on but they are less toxic waste.
     Either way, CFLs should be disposed of properly. Home Depot will take your burnt out but unbroken CFLs. Also, there are online stores, including ours, that can sell you a kit to put your CFL and HID bulbs into. This way you can ship off the materials and know they will be disposed of properly and in compliance with the laws in your area.
     If you do break the glass of your bulb, you may want to wear safety gear (mask, eye protection, gloves) when cleaning up the material.  

Our Picks:

     Some people decide that CFLs are the only type of bulb to have in their house or business. That is fine. The only three recommendations we would make is that you buy ENERGYSTAR approved bulbs and that you dispose of them properly.  The third recommendation is that you look carefully to see if the dimmable CFLs you buy will work in the dimmer circuit.
     If you are open to having different bulb types in your home or business the saddle point for a reasonable return on investment for CFL appears to happen in the 1hour to 6hour bulb range (bulb used on average 1 to 6 hours a day). We say this because CFL bulbs have a higher initial cost than incandescent but lower than LEDs. This will all depend on what you get charged for your power consumption. Use the calculator below to help you find your saddle point.
     There is a good variety of CFL bulbs at our Green Irene store. You can look on their Knowledge base to find specification sheets. We also have a growing number of CFLs on our Amazon.com store.

Specification sheets for products we sell.

Check here to see if there are rebates in your area for purchasing these products.

LED Bulbs


   The LED (Light Emitting Diode) is a very different type of bulb than the rest talked about here. When first used (about 5 decades ago) they were mainly used as indicator lights on devices. When introduced into the lighting industry they could not put out very much light and it was highly directional.
     LEDs are still like that but much has been done so each LED can produce more light. Also, LEDs are now put into arrays so that they can put out even more light in more directions.  
     One reason people decided that LEDs might be a viable alternative to incandescent lighting is the fact that they are so efficient and have a very long theoretical life expectancy.
    The LED industry is making great strides to make light bulbs for a multitude of uses. They are no longer just considered for night lights and flashlights. And as the industry develops we see this type of bulb a very viable candidate to replace most of the other types of bulbs out there.  
     Currently most of the industry is "in development" but as time goes on, the products will stabilize and become more accepted as the way to go for lighting needs.
     Here we will discuss the advantages and disadvantages to trying to fill your lighting needs with LED bulbs.

Energy Efficient:

    Energy efficient? Yes Sir!!  Comparing LEDs to CFLs and incandescent, LEDs are the clear winner. Incandescent are about 5% efficient, CFL are near 20% and LEDs are about in the 40% range. The life expectancy of LEDs can be near 50,000 hours (6 years if on continuously). By far, this seems to be the technology to use for all your lighting needs.
     However, there may be some issues with the color of the bulb lasting all the way to the end of life expectancy. Currently, there is research trying to solve this problem but this can be a very big issue for traffic light where the color of the light needs to be the same for years. 
     However, cost efficiency is a different story. These bulbs can be very expensive. However, your return on investment may occur very quickly depending on use. You can prove that to yourself with the calculator below (also look in "Our Picks" section). 
     Some LEDs will qualify under certain performance standards. ENERGYSTAR has some standards but it appears they are not specific to LED bulb.
For more information about agencies that create standards click here.


    Most applications of LED bulbs are designed to go into standard bulb sockets. There are all kinds now with the E(Edison)- series base, the GU (twist and lock) type base and the multiple pin types. Even though these may exist you might be hard pressed to find them in the hardware store just yet.
     Some of your lighting applications may be for dimming. If an LED is designed for dimming than it should go the full range of <10% bright to 100% bright but you must buy the bulbs that say "dimmable".
    There are just a few lamp types with the LED completely built into the device. These lamps are fairly cheap and will last for many years, so you probably won't have to replace the bulbs and are mostly meant as a disposable device anyway.
     Some LED models may be a bit of trouble to operate if the temperature takes big swings so make sure the you see the operating temperature of the bulb.
     Look in our "Lighting Facts" section for more information about color, dim ability and other lighting factors.


LED pic   An LED bulb is pictured to the left. There is nothing here that is toxic to the environment. Many diodes are made with materials like Gallium, Aluminum, Arsenic Zinc, and a few other elements. It is a very small portion of the semi-conductor. From this little structure a bulb is built around it. It is connected to a circuit that turns the AC power into DC power. Thediodemount01 package is then mounted into an aluminum housing and usually a plastic cap over the top.     
     The unit may have a little Arsenic or Lead but it is considered benign to regulating agencies (and the environment).
    There are many government agencies still "catching up" to LED technology but there are a few things we can say about the disposal. From a recycling point of view, these LED's are usually housed in a huge Aluminum heat sink, which is recyclable. The LED, circuit and plastic cover probably are not. The packaging the bulb comes in is usually some flashy non-recyclable plastic package. We would like to see them come in corrugated one day but today we guess they need to be seen.
     If you want to throw the bulb in the land fill LED bulbs are usually considered toxic free. The National Measurement Office (UK) does certify LEDs. If the LED carries the RoHS approval it means the bulb is toxic free and can be thrown into the land fill.

Our Picks:

    We venture to say that all 24hour and 12hour light applications will have a quick return on investment. For some of your other applications such as the 10hour and 8hour lights the return on investment is going to take a little longer but you will achieve a reasonable saddle point.  For the shorter lights you will just have to use the calculator below to see what is right for you.
24hour applications:
exit sign  Exit Sign. These have to stay on 24 hours a day. Therefore, they pay for themselves in a short time.

eaglelight T8 LED bulb    T8 LED bulbs from Eagle light. These are rated at about 40,000 hours and they have several lengths. Could also be good for 12hour lights and maybe all the way down to 8hour lights. See our write-up about converting from T12 to T8 bulbs and use the calculator below.

12hour applications:
street warehouse light Warehouse and Street Post lamp. Replaces up to 250 Watt CFL lamp and uses only 65 Watts and rated at about 40,000 hours of operation. 13" long.  Also, check out the LED section of our Amazon.com store in the "Outdoor High Power" for other bulb types (mostly commercial). For outdoor residential, you have many bulbs to choose from. Take a look at the LED section of Green Irene or look at the growing number of LED's we have in our Amazon.com store.

10hour and 8hour application:
     Costs have come down for many LED's that are UL listed and RoHS approved. Look at our Amazon.com Store and then use our Green Calculator below to determine feasibility of your 10hour to 8hour bulbs.

6hour to 1hour application:
 We aren't going to mince words here. Unless you are living in a very high price utility district, or have great rebates, or are tired of bringing your bulbs to Home Depot, or just want to have a consistent technology for your bulbs, LED bulbs may not be be a good bulb (return on investment perspective) for this type of bulb application. Look around in our stores and use the green calculator below to determine feasibility.

Specification sheets for products we sell.

Check here to see if there are rebates in your area for purchasing these products.

Other Types of Bulbs


    There are many other types of bulbs out their. All designed for a specific application in mind and all doing well for their original design purpose. Some require more than a bulb, but special ballasts, fixtures and switches. Many of these technologies have tried to extend their application into other areas that they may or may not be well suited for.
      When Greencompletely.com researched these technologies, there was great effort on our part to give these technologies a fair handling for energy conservation and waste creation. 
     Below you will find our research of those technologies. What we can say is that for the original purposes these technologies were a good fit. However, as these technologies try to be lighting solutions in a larger variety of areas, many fall short. We are not saying they are worst than old technology, it is just they may not be as good as the new technology.


     Halogen bulbs are constructed in a very similar way to incandescent bulbs. They both have a Tungsten filament inside an encloser with a small amount of gas.  However, for Halogen the encloser is quarts and the gas is from the halogen family of elements (Fluorine, Chlorine, Bromine, Iodine, Astatine). The gas allows the Tungsten, when boiled off, to come back to the filament. That together with the quarts encloser allow the temperature of the bulb to get a lot hotter.
     This gives a few benefits. Since it can burn hotter than a normal incandescent the color temperature can be higher so you can get into the cooler blue color. Also, it can send out much more light. A few of these factors also contribute to the bulb lasting a little longer than an incandescent bulb (2,000 to 4,000 hrs). Their CRI is about 100 for most all of these bulbs.
halogen light bulb     Handling of these bulbs needs to be done with great care because finger oils can break the bulb. Usually you will need to handle them with a tissue.
     There are a few draw backs to this type of bulb. Since they burn at a higher color temperature, there will be UV light coming out of it (sometimes they will have UV filter in the bulb). Since the bulb burns so hot, in some cases, this bulb type is a fire hazard. When the bulb fails it can do so catastrophically.
     Disposal/recycling is not bad for this type of bulb being made of Tungsten, a little metal, glass/quarts. This can generally be thrown into the land fill. Recycling would be very difficult.

Metal Halide:

    The next three bulb type we discuss are High-Intensity Discharge (HID) bulbs. This type of bulb was originally developed for industrial facilities in the 1960's as an efficient light source. Now they are being developed for commercial and residential use.  
     Yes, we said efficiency. So why are people in the green industry talking about this as a good alternative? We will discuss a possible reason in a bit but lets take a look at how they work.
     Metal Halide bulbs work by passing an electrical arc between two electrodes through a gas that contains Argon, Mercury and Halide gases. As the temperature and pressure build, the bulb produced a lot of light. An electrical ballast is required for proper bulb operation. The bulb needs ventilation because they get quite hot and can take as long as 5 minutes to get to full brightness. These bulbs tend to have a 12,000 to 20,000 hour life expectancy. Generally the CRI is about 85 for this type of bulb.
metal halide bulb     Based on the description of the bulb it seems like it would be impractical to have these bulbs in a residential setting because of the ventilation needs. Most will put out UV radiation but many will have a filter to protect you.
     At the end of the life of these bulbs they can go through "cycling" which means that it will turn on and off. When that is happening the unit (ballast/bulb) is drawing much more power than first new. The very end of the bulbs life could be with an explosion but this is quite rare.
     from a disposal/recycling perspective we did mention the bulb contains Mercury which can present a disposal problem. In general you will have to ship the bulbs to recycling facilities. Go here to see the shipping containers available at Green Irene.

High/Low Pressure Sodium:

   Sodium lights are also a type of HID light. In this case the vapor is Sodium.  
     Low pressure bulbs put out mostly yellow light. The vapor in the bulb is mostly Sodium but also has a little Neon and Argon. This is contained in a borosilicate glass. Their CRI is about 5.
     High pressure Sodium bulbs are like the low pressure ones but they also contain Mercury. This allows more colors to join the yellow of the Sodium so that the bulb is whiter. That means that they will also produce UV light as well. This type of bulb requires a ballast and special fixtures to operate. Their CRI is about 25.
     As with many HID bulbs, they will use more power near the end of their life and may go through "cycling" leading to a violent death. Most of the time they just burn out. These bulbs are estimated to last 16,000 to 20,000 hours.
sodium pics      As with many HID bulbs, they will use more power near the end of their life and may go through "cycling" leading to a violent death. Most of the time they just burn out. Remember, the power used by the bulb/ballast is not just what is printed on the bulb.
     These lights are generally used for grow lights, street lights, and other applications that are well ventilated.
     From a disposal/recycling perspective the HID light needs to be disposed of properly. Go here to see the shipping containers available at Green Irene.

High/Low Pressure Mercury Vapor:

     Like the other HID light bulbs this also sends an electric arc across the electrodes. The vapor is Mercury but since it is a liquid when first turned on there is a third electrode  that arcs and warms the Mercury. There is also Argon gas in the bulb.
      This is a very efficient bulb (better than incandescent and some CFL).  It also has a fairly long life expectancy (10,000 -20,000 hours). The bulb requires the use of a ballast because the bulb needs a constant voltage. The price is reasonable for the lifetime and amount of light they put out.
     Mercury bulbs tend to be more on the blue side and also a clear bulb would put out ultraviolet radiation. However, the bulb pictured on the right has a coating of Phosphorus that makes the output light a little whiter and absorbs much of the ultraviolet light coming from the inner bulb.  Its CRI is about 50.
mercury vapor bulb 125 watt     Most of these bulbs just burn out at the end of their life. This is because the gap between the electrodes gets too large. There is low risk of violent death for these bulbs however there is something called lumen depreciation. In other words, at about 15,000 hours of operation, the bulb/ballast will consume the same amount of power but produce 50% less light.
     From a disposal/recycling perspective, this is a Mercury bulb. Therefore, certain regulations have to be observed for disposal. Go here to see the shipping containers available at Green Irene.

Other Bulbs:

    We have covered several types of lighting technology here. There are many more types but they are mostly specialized for different applications. In other words, you will not see these other types lighting the work rooms of factories or in peoples homes. Therefore, we will give you some names of other lighting systems and leave it up to you to do more research if you want.       Some of the other types are: Nermst, Deuterium arc, Neon, Sulfur, Xenon arc, black light, tanning light, Carbon arc, Hydrargyrum medium-arc iodine (HMI), Hydrargyrum quartz iodine (HQI), Radio luminescence, Plasma and more.

Light Bulb Facts


    There are a lot of choices out there for lighting your home and business. We feel that knowing a few lighting facts will help make the trip to the hardware store (or the online bulb store) more efficient.
      At Greencompletely.com we have heard many problems people are having. We have heard complaints that the CFL's have the wrong color. That certain bulbs do not live as long as advertised. We have heard that dimmers don't dim and some bulbs look stupid.  
    We will help you find answers before you make those expensive buying decisions. There is nothing worse than spending a lot of money and the bulb does not work the way you think it will. We have identified a few lighting facts that will help you make confident buying decision in this section. We could cover more, but if you take a few minutes here, you could dispel some of the confusion that people commonly have about light bulbs.

Color and CRI (Color Rendering Index):

    Color Rendering Index (CRI):  This is a measure of how a light source can reproduce the colors of various objects the light source is illuminating. It has nothing to do with the color of the light bulb. This "color rendering" of objects is compared to natural or ideal light and is on a scale of 0-100. The "ideal" light is incandescent bulb and they have a CRI of 100. Any light bulb with a CRI of 80 or more is considered to be very good. Below that are not as color faithful.
Here is a card we developed to help you determine if a bulb has good color rendering. This is the Color/BW test.

1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6

This is the Color test.
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6

This will be a printable pdf soon with instructions.

     Color: The color of the bulb is a bit different. This is the perceived color of the bulb as you look at it. Words like "warm white" or "cool white" have been used to describe these colors.
     Light bulb colors are specified by a unit called Kelvin (K). This is a temperature measurement very much like Celsius. Without getting into the scientific explanation as to why, what we will tell you is the range of this measure for light bulbs is usually 2,700K to 6,500K.
     The lower range (2,700K to 3,300K) is considered to be the "warm" colors and is more of a yellow color. The highest part of the range (5,000K to 6,500K) is the "natural or daylight" part of the range and is a little bluer. The middle is considered the "cool" part of the range. CRI tends to be a little lower on the lower side of the Kelvin range.

color temperature This is a picture, in general, of what the illumination is like for the different temperature ratings of the bulbs.
The different technologies of the bulbs will give off very different CRI's and colors. We have prepared a table of some of the typical values for the different lighting technologies.

Bulb Type Color(K) CRI
Low-Pressure Sodium
Clear Mercury-Vapor
High-Pressure Sodium
Coated Mercury-Vapor
Halophosphate Warm-White Fluorescent
Halophosphate Cool-White Fluorescent
Tri-Phosphor Warm-White Fluorescent
Halophosphate Cool-Daylight Fluorescent
Quartz Metal Halide
Tri-Phosphor Cool-White Fluorescent
Ceramic Metal Halide
Incandescent/Halogen Bulb

Lumens/Illumination and Efficiency/Efficacy:

    Lumen/Illumination: This is a measure of the strength of a bulb (or how much light it puts out). Since it is usually printed on the box the bulb comes in we will discuss it a little. The actual measurement of Lumen assumes that the bulb sends light equally in all directions. That is not quite true for all light bulbs (like LED). However, it seems to be a good measure of a bulbs light output.
     In practical terms, a 100 Watt incandescent bulb will put out about 1600 Lumens. That same Lumen level is achieved with a 23 Watt CFL and about a 10-12 Watt LED bulb. This relation is not quite linear. A 60 (not 50) Watt incandescent will put out 800 Lumens. That is about a 13 to 15 Watt CFL.
     What may be a more practical unit of measure is the LUX. This is basically Lumens/Meter^2, which is the amount of light falling on a given area. Below we show you a table of different Lux values. This can possibly help you decide what power of light to use for your applications.
    Efficiency/Efficacy:  These are easy terms to mix up and their definitions sound similar. Efficiency and efficacy are even used interchangeably in some articles that are published. Without splitting hairs we will just say they define power used vs. light produced for light bulbs.
     We have prepared a table showing how the different light bulb technologies stack up in efficiency/efficacy. The table does not take into account some of the accessories (ballasts and special circuits) that these lighting technologies need to operate.

Bulb Type
Metal Halide
High/Low Pressure Sodium
Low up to 200, High up to 100
High/Low Pressure Mercury Vapor
* In the lab have seen performance as high as 150 Lumen/Watt. Given the directional nature of this type of light source, the efficacy is hard to measure.

How much lighting does my business or home need?

     There is no good way to answer this because your lighting is your lighting. Engineers and Architects have spent a lot of time making measurements and developing tools just to help you figure out what is right for you.
     We will provide you some of those tools  to help you get started but this is ultimately up to you. We will start with a table of values for some lighting conditions that you are probably familiar with.

Full Daylight
Overcast Day
Very Dark Day
Deep Twilight
Full Moon
Quarter Moon
Overcast Night
    What lighting is best for your home or business? There are a few "rules of thumb" for different situations. However, most of the lighting situation we have seen fall in the 100 to 1,000 lux range. A range higher than that (1,000 to 10,000 lux) is for work requiring exacting, visual tasks. Below that range is more like dark corners of bars and things like that.
    The 100-300 lux range is good for most homes or businesses. Supermarkets and Mechanic shops would probably want their lighting in the 750-1,000 lux range.
     What range is right for you? You may not have fancy light meters or all of the necessary tools to figure out every little detail. You may start by just looking around your home or business. Is is too bright (dark) in some places? Will the time of day influence the light in the building? Can your employees or family get everything done? These questions will not get answered over night. You may want to let a few seasons change so see how the lighting changes before you do anything. Remember, this is your home (business), make decisions that are right for you. 

Dim ability:

     In the past, the ability for a light to dim was assumed. All that was required was the light switch to have a dial or slider that adjusted the amount of power supplied to the light bulbs. The incandescent bulb would be dim for low power and bright for high power and we didn't need to worry how the switch and bulb were designed.
     Today, that is still essentially true for incandescent bulbs. However the "new" technology lights may require more specialization in design to work on a dimmer switch.
     The switch: Light switches today are very different than decades ago. Some have built in timers, motion sensors and dimming circuits. These dimmer circuits were required to change in 1995 to accommodate the newer types of light bulbs (CFL and others).
     Without getting too complicated, the older switched worked by lowering the voltage of the power supplied to the bulb. The newer technology lowers the power by chopping up the electricity supplied to the bulbs. Since this is more complicated to do it requires a little more circuitry in the switch.
     The buzz: Sometimes when you dim a bulb(s) there is a buzz. Sometimes that is the bulb and sometimes it is the dimmer switch. There can be a great variety in the construction of either. However, if you have a well designed switch and a well designed bulb you should not hear much buzz.
    The bulb: Just about every incandescent bulb can be used on a dimmer switch. However, if you want to put a CFL or LED on a circuit that is dimmable you need to make sure the bulb is designed to be dimmable. That information is stamped on the box. If you are buying bulbs from a web site make sure it states in the description that it is dimmable.
     According to our research, "dimmable" CFL bulbs may not go through the entire dimmable range (70% - 100%) before they turn off. Yes, they are dimmable, they just don't always go that dim. Dimmable LED's, however, do seem to go from <10% to 100% on a dimmer circuit. The only CFL that we have see that may be completely dimmable is a product from PureSpectrum. They are available at out Amazon.com store.  They appear to work well when a single bulb is on a dimmer. We are unsure how they will perform on a circuit that has multiple bulbs.
     A CFL or LED designed to be dimmable may also be a little more expensive than a non-dimmable bulb. This may be due to a few facts. The bulb will need a bit more circuitry to be dimmable. Many times, these bulbs are built as down lights or recessed light and may need more hardware to keep it from overheating.
     It is recommended that when putting bulbs in the same dimmer circuit that they be all the same type of bulb.

Conversion From T12 To T8 Fluorescent Tube Light:



     Videos are a good way to learn and at Greencompletely.com we love making them. Watch this area for more videos about different aspects lighting.

Overdrive Dimmable PAR 30 Bulb:

More vids coming:
More vids coming:



Green Calculator:

Light Bulb Calculator
     Because bulbs have different life expectancies, we will calculate a daily cost of ownership based on "Initial Bulb Cost". Use the "Set Up Costs" for initial one time costs (such as an electrician or changing out a fixture). Don't forget ballast replacement in your costs. Here are some average life expectancies, you do not have to use them for your calculations:
Average life expectancies:
Bulb Type Life Expectancy(Hr) Bulb Type Life Expectancy(Hr)
2,000 - 4,000
T12 Fluorescent Tubes
Metal Halide
12,000 - 20,000
T8 Fluorescent Tubes
20,000 - 30,000
High/Low Pressure Mercury Vapor
10,000 - 20,000
T8 LED Tube
35,000 - 45,000
High/Low Pressure Sodium
16,000 to 20,000
LED Bulb
25,000 to 50,000
Current Light Bulb: Replacement Light Bulb:
Life Expectancy(Hr): Life Expectancy(Hr):
Avg. Hours A Day Operation (Hr): Avg. Hours A Day Operation (Hr):
Initial Bulb Cost ($): Initial Bulb Cost ($):
Electricity Cost ($/KwHr): Electricity Cost ($/KwHr):
*Wattage Of Bulb (W): *Wattage Of Bulb (W):
Set Up Costs ($):
* Remember to include power used by ballast.
Is everything filled in above?
Current Light Bulb: Replacement Light Bulb:
Bulbs Used Yearly: Bulbs Used Yearly:
Yearly Power Usage (KwHr): Yearly Power Usage (KwHr):
Yearly Power Costs($): Yearly Power Costs($):
1Total Yearly Costs($): 1Total Yearly Costs ($):
1 Does not include your labor costs to change bulbs.
Yearly Power Savings (KwHr):
Yearly Cost Savings ($):
Return on Investment: Years

Glossary Of Terms:

Dimmable: The capability of a light bulb to go from no (or little) light to full intensity using a sliding (or dial) controlled light switch.

Life Expectancy: In this context, it is the number of hours a light bulb is expected to operate before it burns out. An average.

PAR: Parabolic Aluminized Reflector, the most common types are 120V  PAR 20, 30, 38  (other sizes being 16,56 and 64) and usually put in recessed lighting fixtures indoors or in outdoor spot or flood lights. Diameters of PAR bulbs: 20 - 2.5in, 30 - 3.75in, 38 - 4.75in.

Xhour light: A term created by Greencompletely.com to classify use of a bulb. The "X" stands for the average hours of use a day a light bulb has. A bulb that is always on is a 24hour bulb, an outdoor light is a 12hour bulb, your living room light might be a 4hour bulb.

Saddle Point: In the context of going green, it is determined when comparing technologies for a particular job. This is were initial cost combine with cost of ownership and return on investment. This could also carry components like waste generated or waste created.

CRI: Color Rendering Index: A quantitative measure of how well a light bulb renders colors of objects so that they look like the true colors to your eye. This scale goes from 0 to 100, with incandescent bulbs being 100. A score of 80 or higher is considered to be a very high score.
LED: Light Emitting Diode. A light with a single or an array of LED's. This is a very small source of light but has high efficiency.

Lumen: A measure of the light power of light bulb. A 100 Watt incandescent light bulb may give off 1,600 lumens where as a 23 Watt CFL may put out the same 1,600 lumens.

Power: Measured in Watts, it is a unit of measure for the amount of electricity used to operate an appliance (a light bulb).

Efficiency: a measure of the conversion of power to the amount of light a bulb gives off. Also a comparison of power used by two different light bulb giving off the same amount of light. 

CFL: Compact Fluorescent Light: a light bulb that uses fluorescent technology and is compact and has a mini-ballast.

HID: High-Intensity Discharge: This is a type of light bulb that passes an electrical arc between two electrodes. This arc passes through Mercury, Sodium or some other type of vapor. Originally developed to make industrial lighting more efficient.

Ballast: A device that conditions the power so that bulbs can function properly. Usually for fluorescent or HID bulbs.


http://www.energystar.gov/index.cfm?c=cfls.pr_crit_cfls; ENERGYSTAR requirements for CFL's, Taken 2/22/12.

Facts about metal halide super efficient, long lasting (10000 hrs), and about halogen, LED night lights and other light bulbshttp://www.lightbulbsdirect.com/page/001/CTGY/MetalHalide taken Feb, 3 2009.

http://www.lightbulbsdirect.com/page/001/CTGY/EnergyStar , Taken Feb,3,2009

http://www.lightbulbsdirect.com/page/001/CTGY/LED taken Feb, 3 , 2009

Consumer tests on CFLs http://www.consumerreports.org/cro/home-garden/home-improvement/hardware-building-supplies/lightbulbs/compact-fluorescent-lighting-10-07/overview/bulbs-ov.htm Taken Feb,3,2009

Tips about how to use CFLs. Popular Mechanics, Nov, 2008, pg. 96, "19 ways to slash your utility bill", by Jim Gorman.

http://en.wikipedia.org/wiki/Light_bulb#Bulb_shapes.2C_sizes.2C_and_terms taken 4/16/09. Par bulb explanation.

How dimmer switches work: http://home.howstuffworks.com/dimmer-switch.htm Taken 11/15/10.

http://www.engineeringtoolbox.com/light-level-rooms-d_708.html taken 11/22/10, Illumanance - recommended light levels.

http://www.ehow.com/how_5919966_dispose-halogen-light-bulbs.html , Disposal of Halogen bulbs. Taken 2/28/12.

http://en.wikipedia.org/wiki/Color_rendering_index , Wikipedia's write up of Color Rendering Index, Taken 2/28/12.

A Short Guide to Lamp & Ballast Disposal , taken 3/1/12