Have you ever wondered how many LED lights, or LED Lumens, do I need to light a room?
Here’s how to determine how many LED Lumens you’ll need to properly light your space.
How much light is enough light? The question is difficult enough but when faced with having to calculate how much LED lighting you need to create a well lit space, it can become a bit more complicated.
A measurement of light emitted by a source, whether it’s LED, Fluorescent, Halogen, or Incandescent. This is also known as “brightness” or “light output.” Your reference point: A standard 100-watt incandescent light bulb produces about 1,500 – 1,700 lumens.
Not a measure of brightness; instead, it’s a measure of how much electricity (or energy) a bulb consumes to reach its claimed brightness. Each type of light source, LED, Fluorescent, Halogen, or Incandescent has a different lumen-per-watt ratio. Below we’re going to use lumens as a measurement to make sure we have enough light for a space.
Since we’ve conflated watts and lumens, it’s easier to talk about bulbs in terms of watts. So if a 100-watt incandescent produces 1,500 lumens, and a 10-watt LED does the same, the 10-Watt LED may advertise “100-watt equivalent” on its label.
Here’s a wattage equivalence chart, but note that lumen-per-watt ratios can range mildly, even from LED to LED products.
The number of lumens a bulb produces for each watt it consumes. The higher the number, the more efficient the bulb. For example, lighting products that have earned the ENERGY STAR label are high efficacy, meaning they deliver the same features while using less energy.
The Breakdown— How Much Light is Enough Light?
Determine Room Square Footage. Multiply the Length times the Width of the Room to get the Room Square Footage. For example, if the room is 10 feet wide and 10 feet long, the Room Square Footage will be 100 square feet.
Determine the Foot Candles by Room Type or Room Purpose. A foot-candle is how bright a light is one-foot away from its source. Lighting requirements/needs vary depending on the type of room being lit. For example, a bathroom or kitchen will require more foot-candles than a living room or bedroom.
|Room||Foot Candles Needed|
Determine the Needed Lumens
A lumen is a unit measurement of light. To determine the needed lumens, you will need to multiply your room square footage by your room foot-candle requirement. For example, a 100 square foot living room, which needs 10-20 foot-candles, will need 1,000-2,000 lumens. A 100 square foot dining room, which needs 30-40 foot-candles, will need 3,000-4,000 lumens.11
A Quick Summary
For the average space of 250 square feet, you’ll need roughly 5,000 lumens as your primary light source (20 lumens x 250 square feet). In your dining room, you’ll want about 30 lumens per square foot on your dining table (you want to see your food, but not examine it), so if your table is 6 x 3 feet, that’s 540 lumens.
Keep in mind, however, that these numbers are for typical conditions. If you have especially dark colored walls and furniture or if you’re using fixtures with shades, you’ll need roughly an additional 10 lumens per square foot. We based our calculations on 8-foot ceilings. Finally, personal preference will play the largest part in your decision. If you like the room to be especially bright, you may want to add an additional 10 to 20% to our numbers. In fact, the best approach for most spaces is to aim high and install dimmers to bring the light level down to desired levels.
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/.
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.
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.