Compact Fluorescent Lamps (CFLs)

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Introduction

Compact Fluorescent Lights In California, lighting accounts for approximately 28% of home electricity use, and almost 40% of commercial use. As a nation, we spend about one-quarter of our electricity budget on lighting, or more than $37 billion annually. Recently developed technologies can help cut lighting costs by up to 50 to 75% while enhancing lighting quality and reducing environmental impacts.

Technology Options

Two lighting terms to know when choosing appropriate lighting are lumen and efficacy.

A lumen is a measurement of light output from a lamp. All lamps are rated in lumens. For example, a 100-watt incandescent lamp produces about 1750 lumens. When looking for a light bulb, consider the lumen output, rather than the wattage, to determine the light level you need; lumen describes light output, while wattage describes energy used.

Efficacy measures the efficiency of a lamp. This is the ratio of a lamp's light output to the electric power it consumes, and is measured in lumens per watt (LPW).

While we often think of a "lamp" as a light fixture, the term technically refers to the light bulb or fluorescent tube that you use in a fixture. There are two types of lamps that are primarily used for indoor lighting: incandescent and fluorescent.

Incandescent Lamps (Light Bulbs)
The most common lamp in the United States, the incandescent light bulb, was invented nearly 120 years ago, and it still works much the same way today. Inside a glass bulb, electricity heats a wire filament, causing it to glow and give off light. Of course, electrical heaters work in much the same way, and that is why more than 90% of the energy produced by incandescent lamps is heat, not light. As a result, incandescent bulbs are inefficient light sources. The heat they produce can drive up your electricity bill in hot weather if your home or office is air conditioned.

Fluorescent (Lamps and Tubes)
Fluorescent lights are phosphor-coated glass tubes filled with an inert gas and a small amount of mercury. By using a different mix of gases inside, fluorescent lamps offer a wide assortment of light color, ranging from cooler white light to the warm glow associated with incandescent bulbs.

All fluorescent lights need a controlling ballast to operate. The ballast is built into a compact fluorescent lamp (CFL), but is separate from a fluorescent tube. The ballast alters the electric current flowing through the fluorescent tube, activating the gas inside and causing it to glow. Newly developed electronic ballasts eliminate the flicker and buzz that is associated with older magnetic ballasts, which were also heavier and less efficient.

There are two types of fluorescent lamps: tubular and compact.

Tubular fluorescent lamps are commonly used for kitchen and office ceiling fixtures. The "T" designation for fluorescent lamps stands for tubular — the shape of the lamp. The number after the "T" gives the diameter of the lamp in eighths of an inch. The T8 lamp is available straight or U-shaped and has become the standard for new construction. It also commonly serves as a retrofit replacement for 40-watt T12 lamps, improving efficacy and performance.

Compact Florescent Lamps (CFLs) combine the efficiency of fluorescent lighting with the convenience and popularity of incandescent bulbs. CFLs come in pin-based and screw-based configurations. Pin-based models are designed to fit only into fixtures that are designed for fluorescent lighting. Screw-based CFLs are designed to fit into fixtures where you would typically use a conventional incandescent light bulb.

CFLs can provide as much light as incandescents that are roughly three to four times their wattage, saving at least 66% of the initial lighting energy. Although CFLs cost more than incandescents, they last about 10 times as long (10,000 hours or more). The energy savings and superior longevity make CFLs the more cost-effective choice, saving about $25 over the life of the CFL in energy and bulb replacement costs.

CFLs are available in a variety of styles or shapes, including double- or triple-tubes, the popular spiral shape, covered lamps that look like typical incandescent bulbs, and decorative globe and candelabra shapes. The size or total surface area of the tube(s) determines how much light it produces. Manufacturers have worked to reduce the size of CFLs while improving light output and quality — and reducing the cost — so that it is now easy to find a CFL to fit almost any fixture.

Be Sure to Properly Dispose Old Fluorescent Lamps

All fluorescent lamps are considered hazardous waste when they are discarded because they contain mercury, a highly toxic metal. It is estimated that nearly 75 million waste fluorescent lamps are generated annually in California. These lamps contain more than a half a ton of mercury.

On February 9, 2004, regulations took effect in California that classified all discarded fluorescent lamps as hazardous waste. This includes even low mercury lamps marketed as "TCLP passing" or "TTLC passing." Up until February 8, 2006, California households were allowed to discard their own fluorescent lamps as non-hazardous solid waste (ordinary trash). This is no longer the case. Under current law, all fluorescent lamps and tubes must be recycled, or taken to a household hazardous waste disposal facility, a universal waste handler (e.g., storage facility or broker), or an authorized recycling facility.

Where can you recycle the lamps? Call 800 CLEAN-UP (253-2687) or visit the Earth 911 website, and enter your zip code to find the nearest recycling center.

Efficiency Benefits

ENERGY STAR qualified CFLs use 75% less energy and will outlast up to 10 incandescent bulbs. Replacing just five of the frequently used light bulbs in your home can save more than $60 each year in energy costs. If you replace 25% of your lights in high-use areas with fluorescents, you can save about 50% on your lighting energy bill.

The long life of CFLs also can greatly increase convenience and security. Using CFLs in outdoor lighting can provide the assurance that security lighting will remain on when you need it. CFLs will last at least five years in typical indoor applications, meaning fewer trips to purchase light bulbs and fewer times climbing to change bulbs in hard-to-reach places.

The savings from replacing incandescent bulbs with CFLs are summarized by the table below. The values in the table assume that the light is left on for six hours per day and that electricity costs $0.10 per kWh.

  27-Watt Compact Fluorescent 100-Watt Incandescent
Price of Lamps $9.00 $0.50
Lamp Life 1642.5 days (4.5 years) 167 days
Annual Energy Use $5.91 $21.90
Energy Cost over 4.5 years $40.60 $98.55
Lamps Replaced in 4.5 years 0 10
Total Cost $35.60 $103.55
Savings Over Lamp Life $67.95 -

By reducing electricity demand, you reduce the need to burn fossil fuels such as coal, oil and natural gas which, combined, make up almost 60% of the fuel to produce electricity in California. Energy savings from a single CFL replacement can reduce the emission of pollutants such as sulfur dioxide and nitrous oxides that contribute to smog, and can prevent the emission into the atmosphere of at least 112 pounds of carbon dioxide, the most common gas attributed to global climate change.

If you use tubular fluorescent lamps, replacing four T12 lamps and two magnetic ballasts with four T8 lamps and one electronic ballast saves you as much as 40% on energy costs.

Manufacturers

AM Conservation Group and AutoCell Electronics are some of the major manufacturers of ENERGY STAR qualified CFLs. For a complete list, visit the ENERGY STAR website.

Purchasing Tips

  • Look for lumen output. When choosing a light bulb, determine the amount of light output needed, and choose the CFL that provides the right lumen output. Following are average lumen output values for typical incandescent light bulbs:
    Typical light output (lumens) 450 800 1,100 1,600 2,600
    Incandescent Wattage 40 60 75 100 150
  • Check your wattage. Remember that wattage is a measure of energy, not light output. As a general rule, a three to one incandescent to CFL wattage ratio will yield approximately equivalent light output.
  • Check your local hardware and building supply stores and specialty lighting centers for CFLs. There are also many mail order firms that distribute energy-efficient and renewable-energy products.
  • Evaluate the lighting area. CFLs are most cost-effective and efficient in areas where they will be left on for long periods of time.
  • Look for the ENERGY STAR. ENERGY STAR qualified CFLs have gone through extensive quality assurance testing to provide the level performance you want.
  • Use an energy savings calculator. Try ENERGY STAR's CFL calculator (MSExcel File, 84k) to save money with any retrofit you do.

Emerging Technology

Cold cathode fluorescent lamps are one of the latest technological advances in fluorescent technology. The "cold" in cold cathode means there is no heating filament in the lamp to heat up the gas. This makes the lamp more efficient. Also, since there is no filament to break, they are ideal for use in rough service environments where a regular lamp may fail. They are often used as backlights in LCD monitors and exit signs.