Comparison of Home Lighting Technologies

A few decades ago, choosing a light bulb was simple. Household fixtures all used incandescent bulbs and businesses used fluorescent lights. Halogen bulbs were only popular for off-road vehicles as running lights. The consumer's only decision was the wattage of the bulb. Now the choices are diverse and complex. Incandescent, CFL, CCFL, LED, ESL and halogen bulbs are all available for home lighting needs. The different types vary significantly in price, efficiency, usability, legality and eco-friendliness.

Invented in the 1800s, incandescent light bulbs are simple in design. A tungsten filament inside a globe filled with nitrogen is fed with AC power until it glows. Lifespan is between 750-1000 hours for popular bulbs and efficiency is very low, around 2%. Bulbs with up to 5000 hours life exist, but they are essentially 130V models sold to operate at 120V. This makes them run cooler and last longer, but cooler operation makes them even less efficient than 750-1000 hour incandescent lights.

Halogen bulbs simply replace the nitrogen gas in conventional incandescent bulbs with halogen which allows for applying more power for the same lifespan. The hotter the filament, the more efficient the bulb is in creating light. Because of this, halogen designs can be 30% more efficient than nitrogen filled bulbs. On the down side, the higher heat of halogen bulbs requires perfectly clean glass surfaces and high temperature lighting fixtures. Halogen bulbs can cost up to ten times as much as incandescent types of equal output.

The Compact Fluorescent Light or CFL was invented in 1973 at GE but did not gain popularity until 1995 when the patents expired. At that time, inexpensive Chinese imports of CFL bulbs lowered the price to a competitive level for consumers. CFL bulbs now dominate the hardware store shelves. According to a December 02, 2010 NEMA report, third quarter sales in 2010 show that CFL lamps only account for 25% of light bulb sales. However, CFL sales growth is increasing, while incandescent lamp sales are decreasing.

Laws to ban the use of incandescent and halogen bulbs or to set minimum lighting efficiencies have been enacted in many countries. By the end of 2012, all incandescent bulbs will be banned for sale in the European Union. The switch to more efficient bulbs, to conserve energy, has become a popular political mandate.

The typical lifespan for a CFL bulb is 10,000 hours for a bulb that costs about double the price of an equivalent incandescent bulb. A 14 watt CFL bulb has the equivalent light energy of a 60 watt incandescent light. Factoring in the longer lifespan and energy savings, CFL bulbs save 75% in operating cost compared to incandescent lights and are currently the most cost-effective of all the home lighting options. Operating costs are calculated using nine cents per kilowatt-hour and six hours per day use, for a bulb equivalent in output to a 60 watt incandescent lamp.

CFL bulbs take one to three minutes to reach full light intensity, which is considered undesirable by many consumers. A new solution to this problem is a hybrid model that combines a small halogen light into a CFL bulb. The halogen section initially provides full brightness lighting. After the CFL section is fully warmed up, the bulb electronics switch the halogen section off. Just introduced by GE in April 2011, the new hybrid bulbs are four times the price of regular CFL bulbs.

Cold Cathode Fluorescent Lights or CCFL are a variant on CFL bulbs and are commonly used for backlighting computer displays and for scanner lamps in copy machines. They are half as bright, for a given power level, compared to regular CFLs. Versions for home lamp fixtures cost 15 times more than regular CFL types, but do have the capability to be dimmed. They require special dimmer controls that work at 15-20 watt power levels. CCFL bulbs are only functional over 20-100% of their output range when used with dimmers.

LED lamps come in two varieties. One type uses combinations of red, green and blue LEDs to create white light. The other type uses a blue LED with a special phosphor coating on the lens to create bluish white light. The lifespan of the phosphor style LED is limited by the phosphor itself. Lifespans of all LED lamps are more markedly affected by heat than are incandescent or fluorescent models.

LED lamps are currently expensive, but the best models have three times greater life than CFLs and can be up to twice as efficient. The new higher efficiency models provide the least expensive running cost per hour of all the lamp technologies. LED technology has improved rapidly in the last decade, but some LED bulbs sold on the market today use older, less efficient LEDs to keep manufacturing costs down. Because these models use older LED technology, the consumer ends up with a relatively expensive LED lamp with the same efficiency as a CFL bulb. Buyers must pay attention to the lumen output and price when choosing an LED lamp model.

Like CFL lamps, only specially designed LED bulbs can be used with dimmer circuits. LED bulbs have gained market share in flashlights, tail lights on vehicles, grow lights, Christmas tree lights and small reading lamps. For home lighting use, however, it's difficult to sell a $20 LED bulb that is equivalent to a 30 watt incandescent light that costs $0.70. Until manufacturing methods improve to lower costs, LED lights will not be a viable replacement for CFL models.

Electron Stimulated Luminescence or ESL bulbs just came on the market in 2010 and will be available in models that install in standard lamp sockets in mid 2011. ESL bulbs are similar in operation to the classic television picture tube. The technology uses high voltage to accelerate electrons into a phosphor-coated glass surface. When the electrons hit the surface, the phosphor glows. ESL bulbs contain no mercury and work well in dimmer circuits. Early pricing is $20 per bulb for a 19.5W ESL bulb that is equivalent to a 60W incandescent type. Lifespan is 11,000 hours so running costs are over double that of a CFL bulb.

The different lighting technologies have diverse environmental concerns. All fluorescent types, including CFL bulbs, contain mercury that can be released into the home if the bulb breaks. These bulbs should be disposed of through a recycling center that takes electronic waste. LED lights have variable amounts of lead and traces of arsenic but are sealed in epoxy, so breakage in the home is not an issue. Incandescent, halogen and ESL bulbs contain no toxic materials.

In summary, CFL bulbs are the clear winner for the lowest operating costs. Specialized CFL types exist for use outdoors, in enclosed spaces and in dimmer circuits. CFL bulbs come in assorted colors for festive occasions. If the slow warm-up of CFL bulbs is an issue, the new hybrid CFL bulbs with a halogen starter lamp can provide a solution. An effort to reduce the mercury content from four mg to one mg per bulb is under way. Keep an eye on LED bulbs over the next few years, as a large development effort is under way for that technology. LED lighting could still dominate the market. Prices and technical specifications for typical light bulb types in this article are based on data from www.1000bulbs.com.