The amount of light a bulb produces. Depending on which government agency you ask, this is “brightness” or “light output.” Your reference point: A standard 100-watt incandescent produces about 1,700 lumens.
Not a measure of brightness; instead, it’s a measure of how much energy a bulb consumes to reach its claimed brightness.
Fact: We’ve already said goodbye to 75- and 100-watt incandescent light bulbs, and starting January 1, 2014, we’ll also be saying goodbye to 40- and 60-watt bulbs as well. This is due to the Energy Independence and Security Act.
Since we’ve conflated watts and brightness, it’s easier to talk about bulbs in terms of watts. So if a 100-watt incandescent produces 1,700 lumens, and a 20-watt LED does the same, the LED will be sold as a 100-watt equivalent.
The number of lumens a bulb produces for each watt it consumes. The higher the number, the more efficient the bulb. A good number for incandescents is around 18, CFLs around 60, and LEDs around 54.
Turning a bulb on and off, on and off, reduces the Average Rated Life (ARL). Incandescent, halogen, and LED bulbs are less affected by on/off cycles than Fluorescent, Compact Fluorescent (CFL), and HID bulbs. In general, the ARL for a bulb that turns on and off once a day will be much longer than a bulb that turns on and off many times a day.
LEDs dim over time. They’re considered effectively dead when they produce no more than 70 percent of their original brightness. For LEDs, this lifespan is given in hours of years, the latter an estimate based on three hours of daily use.
Typical Average Rated Life (ARL) for Types of Light Bulb
Incandescent 750-2,000 hours
Compact Fluorescent (CFL) 8,000-10,000 hours
LED 40,000-50,000 hours
Based on an assumption of three hours of use per day at 11 cents per kilowatt-hour. For a 60-watt incandescent, it’s just over $7 per year. CFLs and LEDs both come in at about $1.50 per year.
LIGHT BULB TYPES
Three of the most common types of light bulbs are energy-saving Incandescent, CFL and LED.
INCANDESCENT BULBS: 25% ENERGY SAVING
Incandescent bulbs use a filament that’s heated to the point of glowing. The glowing filament produces the bulb’s light.
• Incandescent bulbs last on average 1 year.
• Incandescent bulbs do not contain mercury.
• Can be used with a dimmer switch.
CFLS: ABOUT 75% ENERGY SAVING
CFLs are quiet, instant-on and have warmer, color-corrected tones. They can be used anywhere you would use a typical incandescent light bulb.
• Compact fluorescent lamps (CFLs) last up to 9 year.
• CFLs contain small amount of mercury.
• Available in medium bases to fit standard light sockets, such as table lamps.
LED: ABOUT 80% ENERGY SAVING
LEDs are a type of solid-state lighting — semiconductors that convert electricity into light. They have lower wattage than incandescent bulbs, but emit the same light output. This allows them to produce the same amount of light, but use less energy. As with the CFL, Light Emitting Diode (LED) bulbs are the most energy-efficient light bulb options.
• LEDs are more expensive that the last two options but last up to 20+ year.
• LEDs do not contain mercury.
David Hakimi is a lighting specialist and one of the co-founders of Alcon Lighting. A graduate of the University of California Los Angeles (UCLA), David works on the front lines of the energy-efficient lighting revolution, enabling architects, designers, and lighting engineers to transition from outmoded halogen and fluorescent lighting to what David calls “the ideal replacement for all lighting applications,” —LEDs. David takes particular pride in Alcon’s design, energy, and green building knowledge, tracing his and Alcon’s commitment to quality, innovation, accountability and value back to the lessons learned from his father, a Southern California lighting salesman and consultant for more than two decades. Passionate about reducing climate change and protecting the environment, David has been particularly valuable in ensuring that his clients and customers comply with rapidly-evolving green building codes. You can connect with David on LinkedIn at https://www.linkedin.com/in/david-p-hakimi/.
The Chicago Department of Buildings recently announced that energy design requirements for building projects in Chicago have been updated as part of the city’s multi-phase code modernization process. For permit applications started on or after June 1, 2019, the Chicago Energy Conservation Code (Title 14N of the Municipal Code), based on the 2018 edition of the International Energy Conservation Code, published by International Code Council, Inc., will now apply.
This is the first post in a new series about essential commercial and architectural lighting terms. The terms, which will be presented in sets of five terms per post, are curated. The terms in this post: CRI (Color Rendering Index), Color Temperature, Bluetooth Mesh, Architectural Lighting and UL Vs. ETL Listing.
Our relation to light as humans is complex. Though many of the effects of light on our biology are still unknown, there are several we know and understand. Light also plays a major role in regulating human biological responses, including our internal body clock or circadian rhythm.
As the United States of America celebrates Independence on the Fourth of July, it’s worth remembering lighting’s role in the American Revolution. Revere’s light signal was a backup plan designed to warn patriots in Charlestown, a borough across the river from Boston, in case Revere was arrested by the British occupying Boston and thus unable to initiate the ride.
The Continental Congress passed an act establishing an official flag for the new American republic on June 14, 1777. President Truman declared June 14 as Flag Day August 3, 1949. Anyone considering displaying America’s flag for Flag Day today or on Independence Day on July 4th might want to give some thought to proper illumination.