A single fixture doesn’t always guarantee that you will have a sufficient amount of light in a space. This is why Lighting Specialist often recommend layering lighting to obtain optimal results.
What are lumens?
A lumen is a measurement used to determine the quantity of light.
How to determine the right amount of lumens needed per room?
1) Multiply the width and length of the room to get square footage.
For this example: 11 x 9 = 99sqft
2) Determine the lumens per square foot needed (known as foot candle).
You can use this chart as a guideline:
3) Multiply the square feet by the foot candle recommended for the room. This will yield the amount of lumens needed for the space.
Example: Lighting for 99square foot dinning room
99sqft x 30 foot candle = 2970
99sqft x 40 foot candle = 3960
Approximately 2970 to 3960 lumens needed for the space.
4) Consider other factors that may alter the amount of lumens you need for the space.
Consider what activities are going to take place in the space; are you needing a lot of light or not much?
Consider the aesthetic of the space; do you have a lot of dark furniture, floors, or walls? How high are your ceilings?
Will the lighting in the room be dimmable or not?
5) Now that you know the general idea of how many lumens you need for your space, the next thing is to determine what product/ products to purchase that will provide you with enough light.
Most lighting manufacturers provide the initial lumen information for their products, but not all will provide delivered lumens. What’s the difference?
Indicates the amount of light given off from the light source, but does not account for other factors that may alter the final output.
Indicates the amount of light given off from the light source after taking into account factors that will affect the final output such as lenses and diffusers. As a result, delivered lumens are lower in comparison to initial lumens. Expect that approximately only 80% of the lumens will be delivered.
Since incandescent and fluorescent use wattage as a measurement, you can use this chart as a guideline to know how much lumens you will need for a space if you choose to use these options.
Remember that a single light source might not yield you with enough lumens, so it is advised to layer lighting. This also allows you to adjust the level of lighting depending on the activities taking place within the room.
For more information on lumens or how to effectively layer lighting, feel free to contact our ALA Lighting Specialist. Our team is always happy to help!