Bulb Basics

shapeKey A line Shaped Bulb Twist Shaped Bulb Blunt Shaped Tip Bulb Reflector Shaped Bulb Bulged Shaped Bulb
Bulb Name Arbitrary
Twist Blunt Tip Reflector Bulged Tube
Symbol A B BR/R BT
Common Fixtures Table Lamps Table Lamps Chandeliers and
Recessed cans
and track lights
Table lamps
Candle Shaped Bulb Circleline Shaped Bulb G8 120v Shaped Tip Bulb Globe Shaped Bulb Mirrored Reflector Bulb
Bulb Name Candle Circline G8 120V Globe Mirrored Reflector
Symbol CA CIR G8 G MR
Common Fixtures Chandeliers and
Table Lamps Specialty Vanity strips and
pendant lights
Track light
Parabolic Aluminized Reflector Shaped Bulb Reflector Shaped Bulb T4 12v Shaped Bulb Tubular Shaped Bulb
Bulb Name Parabolic
Reflector T4 12V Tubular
Symbol PAR R/K T4 T
Common Fixtures Security fixtures,
recessed cans and
track lights
cans and
track lights
Speciality Appliances and

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A-Shaped Bulbs
PAR-Shaped Light Bulbs
Linear Fluorescent Light Bulbs

Flood and Spot Lights
For recessed light fixtures and track lighting, floods project a wide beam of general light and spots produce a narrow beam for accent lighting. If standard A-shape bulbs are mistakenly used, 40% of the light is trapped inside the fixture.

3-way light

3-Way Lights
When using 3-Way table and floor lamps, bulbs can provide three levels of easily controllable light. A low setting saves energy, medium is for general lighting and high is perfect for specific tasks like reading.


Globe Lights
Globes add a decorative flair and work great in bathroom vanity fixtures and hanging pendants.

garage door opener

Garage Door Opener Lights
Using light bulbs specified for garage door openers is very important, since they are designed to withstand shock and vibration.

ceiling fan light

Fan Lights
A fan light bulb is designed to fit comfortably inside the fixture and can withstand the constant vibration of ceiling fans.


Appliance Lights
Refrigerators and ovens need lights designed to hold up against shock vibration and have special basing cement to ensure long life in extreme temperatures.

Halogen Capsule Light

Halogen Capsules
Use halogen capsules, which are tiny bulbs with pins, for under cabinet lighting, task lights and outdoor landscape lighting. They are available in 12 and 120 volt versions, with the base numbers representing pin spacing in millimeters.

bug light

Bug Lights
A special yellow coating on bug lights minimizes attractiveness to flying insects.

night light

Night Lights
To provide a small amount of light in a dark room, use small long-life bulbs designed to fit inside night light fixtures.


Compact Florescent Non-Integrated (PL)
A special yellow coating on bug lights minimizes attractiveness to flying insects.

Select the Right Color Temperature

How do you calculate the cost of operating a light bulb?

To calculate the bulb's cost of operating for one day, multiple the bulb wattage times the daily hours used, then divide by 1000 and multiply by your local utility cost per kwh (ex: 75W x 4 hours divided by 1000 x $0.10 kwh = $0.03 per day to operate)

Why does my light bulb fail earlier than its specified life?

Light bulb life is based on specified average number of hours (see individual packages for life in hours). A bulb's life can be shortened by shock or vibration, and by overvoltage. Look for longer life vibration resistant and 130V bulbs if life is an issue.

Can my bulb be used with a dimmer switch?

Most bulbs can be used with a dimmer switch. However, fluorescent lighting is not typically dimmable, except for a few CFLs that are specifically designed to be used with dimmers. Check individual CFL packages.

What type of bulb is best for my fixture?

It is best to use the appropriate bulb for a fixture to maximize light output and ambience. Refer to the Bulb Finder to help choose the right bulb for a fixture.

I have recessed lighting in my ceiling, what is the best bulb to use?

Use a PAR, BR, or R bulb, either a flood or spot depending on your application. Reflector bulbs are designed to direct all of the light from the front of the bulb (non-Reflector type bulbs direct light from all sides which gets trapped inside the recessed fixture).

What if I need a large quantity of light bulbs?

See your local Contractor Services Desk. They can special order job lot quantities for more than 3000 bulb types.

What's the difference between incandescent and halogen type bulbs?

Both incandescent and halogen light bulbs use a filament to produce light. Halogen bulbs operate more efficiently than incandescent bulbs because the filament is incased in a glass capsule, in a halogen gas atmosphere. Halogen lasts up to 3 times longer than equivalent incandescent bulbs, and produces a whiter, brighter light.

Does a halogen bulb produce more heat than an incandescent?

No, an incandescent and halogen bulb of the same wattage will produce approximately the same amount of heat. When operating, both bulbs will be hot to the touch. Both should be turned off and allowed to cool before handling.

What is an Enhanced Color bulb?

There are two types of Color Enhanced bulbs.
(1) Bulbs that contain the rare earth element neodymium in the glass. These bulbs filter out much of the dulling yellow cast common from ordinary light bulbs to provide a pure, clean light.
(2) Bulbs that use a distinctive blue coating which reduces dull light effects to provide a more vibrant and natural light, similar to natural daylight.

What is a CFL?

CFL stands for compact fluorescent lamp. It is a small fluorescent light bulb that uses 75% less energy and can last 10X longer than a traditional incandescent bulb.

How do I dispose of a CFL when it burns out?

It is best to recycle your CFL. At any Home Depot, customers can bring in any expired, unbroken CFL bulb. Just look for the CFL recycling signs and collection units in the stores or check with your town for recycling programs. Visit our Eco Options site to learn more about CFL recylcling.

What should I do if I break a CFL?

Because CFLs contain small amounts of mercury, the EPA recommends certain clean-up and disposal guidelines be followed. For a complete set of these guidelines, go to www.energystar.gov/cfls.

What is the difference between a CFLi and CFLni?

CFLi stands for integrated CFLs. They are the traditional energy saver compact fluorescents that screw into standard fixtures. CFLni stands for non-integrated CFLs (also known as PL lamps). They are a two-piece system utilizing a base and ballast in the fixture, and a detachable fluorescent tube, or bulb. They are most popular for commercial applications.

What is ENERGY STAR® and why does it matter?

ENERGY STAR is a collaboration between the Dept. of Energy and the EPA that sets minimum efficiency standards for energy savings in appliances, light bulbs and other devices. To learn more about ENERGY STAR and ENERGY STAR rated products, visit www.energystar.gov.

Why do linear fluorescent lamps need a ballast?

Fluorescent bulbs use a combination of gas, electricity and coating to produce light. The ballast regulates the amount of electricity flowing through the bulb so that the right amount of light is emitted.

What do the different 'colors' of fluorescent lamps mean?

Color describes the color temperature and CRI. Colors range from warm to neutral to bright white.

Should I wait until a linear fluorescent bulb burns out before I replace it?

There's nothing wrong with this practice, however fluorescent bulbs produce less light (lumens) over time. By the time it burns out, it may produce just 75% of its original level. The color will change slightly over time, so if you replace just one bulb at a time in a multi-bulb fixture, the new bulb will be brighter and a slightly different color than the others.