Lighting FAQs

Frequently Asked Questions

How is the hour rating on a bulb determined?

Lamp manufacturers test large groups of lamps to estimate the average burn time that can be expected. In the lighting industry hour ratings are referred to as Average Rated Life. Some lamps will last longer and some will not last as long as the Average Rated Life but this provides the best estimate.

How do you measure the length of a lamp?

The length of a lamp can also be referred to as the Maximum Overall Length or M.O.L. Most lamps are measured from end to end including the base. Linear fluorescents are an exception; they include the actual socket in their M.O.L.

Why does a light bulb turn black?

Over the life of an incandescent light bulb the filament begins to deteriorate and the particles will settle on the inside of the glass. In return the bulb will take on a grayish appearance and a slight decrease in light output may occur. For fluorescent bulbs only the ends will blacken as the bulb is burned. Each time the lamp is turned on and off the emissions material settles on the inside of the glass. Extreme darkening generally indicates the bulb is about to burn out.

What is the difference between 120 volt and 130 volt? Line voltage in the United States is 120 volts, however lamps are often manufactured at 130 volts to increase lamp life and to offer protection against power surges. Please note you may use a 130-volt lamp in a 120-volt socket without issue, but you will sacrifice some light output. Rule of thumb: a 130-volt lamp may last up to twice as long but can be up to 15% dimmer than a 120-volt lamp.

How do I know what wattage to use in my fixture?

Whenever replacing a lamp you must check the fixture for wattage and voltage requirements. With an incandescent light fixture wattage becomes a preference depending on how much light is needed. With fluorescent or high intensity fixtures the wattage is specific to the ballast built in the fixture. CAUTION: Using the wrong lamp in a fixture could cause the bulb to burnout early and may create a fire or safety hazard.

What is Kelvin temperature?

Kelvin temperature is often referred to as color temperature. It describes the actual appearance of the light itself. Higher temperatures represent a "cooler" appearance while lower temperatures represent a "warmer" appearance. 2700K – 3000K = Warm White 3500K = Neutral 4100K = Cool White 5000K – 6000K = Daylight

The GoodBulb customer service staff can help you choose the best light for your needs.

What is the difference between medium and mogul base lamps?

Medium base or "standard" base is the most frequent choice in everyday household applications; a standard household bulb is a medium base. Many industrial applications require a mogul base lamp which is larger in size than the medium base. GoodBulb carries both types of lamps.

What is an ANSI code?

An ANSI code is either an alpha or numeric designation that ensures certain specifications such as wattage voltage shape and base. ANSI stands for American National Standards Institute. This organization develops voluntary guidelines and product performance standards for the electrical industry and other industries. Bulbs and fixtures are often imprinted with the ANSI code.