Lighting Buyer's Guide

What are LEDs and How Do they Save Energy?

LED stands for Light Emitting Diode. Unlike incandescent bulbs that use electricity to heat a filiment inside the bulb until the filament glows (90% of the energy used produces heat, while 10% is converted into light), LED bulbs require far less electricity to produce a unit of light (about 85% of the energy used by an LED is converted to light). Using less energy to deliver light reduces the amount of electricity that need to be generated, potentially decreasing greenhouse gas emissions while also lowering utility bills. How do you know which LED is right for you? Just like with standard bulbs, the same considerations apply - will it fit, will it be bright enough, and what will it look like when illuminated?

Bulb Styles and Bases - A Quick Rundown

The styles of light bulbs fall into a handful of broad categories, each of which has a letter value. For example, general use light bulbs are in the "A" category. Following each of these letters is a numeric value, representing the width of the light bulb in eighths of an inch. Therefore, an A19 is a general use light bulb that is 19 eighths of an inch wide. The higher the value, the larger the diameter of the light bulb.

Bulb Styles

A Series - Common, general use bulbs for table and floor lamps, sconces, vanities, and ceiling fixtures. Examples: A19, A21
B Series - Decorative bulbs including candelabra, flame tip, and bullet tip for use in chandeliers, wall sconces, and pendant lights. Examples: B10, B11
G Series - Globe bulbs are for general use, often in the open where they can be seen such as multi socket bathroom vanities. Examples: G16, G25
ST Series - Edison style bulbs for decorative lighting, commonly used in vintage style lamps and ceiling fixtures. Examples: ST18, ST19
R Series - Reflector bulbs are used for spotlighting, floodlighting, and down-lighting applications. Examples: R20, R30
BR Series - Bulged reflector bulbs redirect light for a softer appearance, often used for indoor track lighting and recessed lighting. Examples: BR20, R30
PAR Series - Parabolic aluminized reflector bulbs concentrate light in a single area, making them great for outdoor spotlighting. Examples: PAR20, PAR38
T Series - T (tube) bulbs are long, linear LED bulbs that replace existing fluorescent bulbs. Example: T8

Bulb Bases

Screw bases (general and decorative lighting) - Miniature Screw (E10), Miniature Candelabra (E11), Candelabra (E12), Medium (E26)*
Fluorescent pin bases (tube lighting) - Medium bi-pin, single pin
Twist and lock bases - GU10, GU24
*Most common bulb base in U.S.

Lumens, a Measure of Brightness

It is a common misconception that watts is a measure of brightness, but it is lumens that measure the amount of light, not watts. The higher the lumens value, the brighter the light.

Here's a little history:

Beginning in the 1980's many utility-sponsored programs offered rebates to encourage people to which from inefficient incandescent lighting to more efficient fluorescent lighting. In 2007 the Energy Independence and Security Act (EISA) was passed that included provisions to improve the efficiency of lighting through minimum efficiency standards. For instance, pre-EISA, a 1,600 lumen general use lamp would typically consume 100 watts of electricity (16 lumens per watt). Today, because of EISA the efficiacy requirement for lighting, general use lamps must delivery at least 45 lumens of light per watt, which incandescent and fluorescent lamps are generally unable to achieve.

Kelvin, a Measure of Color

The correlated color temperature (CCT) is the color of a bulb, measured in degrees Kelvin. The lower the value, the "warmer" (more yellow) the color of the light. The higher the value, the "cooler" (more blue) the light. The most common color temperature is 2,700 degrees Kelvin (soft white), while a very white light will have a color temperature around 5000 degrees kelvin.

Smart Home Lighting / Smart Bulbs

These days you can replace many incandescent or LED bulbs with smart bulbs. Smart bulbs are available in white or color, and offer a variety of lighting styles. These bulbs make your home smarter; allowing you to control lighting in new and innovative ways. They are wi-fi enabled, allowing lights to be turned on or off through a smart phone, and some offer wireless accessories such as Wi-Fi enabled motion sensors to control the lights automatically.

Light Hue or Appearance: White light smart bulbs usually allow the lumens and/or the color temperature to be adjusted, while color light bulbs can create a rainbow of ambient light based on personal choice

Home-Based Smart Control Options: Smart bulbs can be controlled by apps, smart home assistants, and smart home hubs

Create Custom Presets: Smart bulbs come with multiple presets, such as "Reading Mode" or "Warm Evening Mode." You can even modify or create new presets for smart bulbs, and simply apply the option in the app

Timers: Smart bulbs can be set to turn on or off via app, smart home assistant, or hub

Home lighting updates can provide new lighting capabilties that were previously unavailable, while requiring far less electricity than older technology incandescent and fluorescent lamps.

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Contributor: Al Nadeau, September 12, 2024