8.3 How Much Lighting is Needed

8.3 How Much Lighting is Needed

How much light is needed in a room depends on the task(s) being performed (contrast, requirements, space, size, etc.). There are three different types of task-oriented lighting: Ambient, Task, and Accent. The light requirement also depends on the ages of the occupants and the importance of speed and accuracy of the task.

  • Ambient lighting is general purpose lighting—an example is the lighting used in hallways for safety and security. An illumination of 30–50 fc is generally the maximum that one needs for this purpose.
  • Task lighting is lighting that is designed for specific tasks. Reading and writing are the most light-intensive tasks and require about 50 fc at home. Tasks like cooking, sewing, or repairing a wrist watch require more -- about 200–300 fc. However, the area with this level of illumination will be small. Increasing the light everywhere is not required and is a waste of energy.
  • Accent lighting is the lighting that is provided to highlight certain objects or areas, for example, the use of floodlights to highlight a painting or a statue. Accent lighting also illuminates walls, so they blend more closely with naturally bright areas like ceilings and windows. Accent lighting can be high intensity or subtle.

How Much Light is needed?

Your lighting levels and color temperature is much a matter of preference, but the Illuminating Engineering Society (IES) has come up with guidance to determine the appropriate lighting levels for various spaces in your home. 

Recommended Residential Lighting Levels
Lighting AreaRecommended Foot Candles
Living Rooms, Bedrooms, and Relaxation Areas 10–20 foot candles (ambient).
Kitchen (General)30-40 foot candles
Kitchen (Task Areas - Stove & Sink)50-100 foot candles
Bathrooms20-50 foot candles
Home Office/Reading Area20-50 foot candles
Dining Room30-40 foot candles
Hallways & Entryways5-20 foot candles
Garage (General)30 foot candles
Garage (Workbench) 100 foot candles

Indoor Lighting Levels Requirements

Recommended Commercial Lighting Levels
Indoor Lighting AreaRecommended Foot Candles
Corridors / Stairways / Restrooms10‑20
Storage Rooms10‑50
Conference Rooms20‑50
Gymnasiums30‑50
Merchandising30‑150
Cafeterias50
Classrooms20-100
General Offices50‑100
Manufacturing Assembly50‑100
Parking Lots (security)0.5-3

Color Rendering Index

Lamps are assigned a color temperature (according to the Kelvin temperature scale) based on their "coolness" or "warmness." The human eye perceives colors as warm if they are at the red end of the spectrum, and cool if they are at the blue-green end of the color spectrum.

A series of six black pendant lights display different color temperatures from warm to cool white, marked as 2700K to 6500K.
LED lights with different color temperatures
Text description of the LED color temperatures image.

The image displays a series of six black pendant lights, each suspended from the ceiling, against a backdrop divided into six vertical sections. Each section is illuminated with a different color temperature, ranging from warm to cool white. The leftmost section shows a warm yellow light at 2700K, transitioning to a slightly cooler light at 3000K, followed by neutral white at 3500K and 4000K, progressing to cooler light at 5400K, with the final section showcasing a blue-tinted cool light at 6500K. The walls underneath the lights show the corresponding color temperature numerically, written in colors that match the light above.

Credit: © tonstock / Adobe Stock. Accessed June 14, 2026.

Light sources the color temperatures represent.(0:27)

 (Note: The video has no audio.) 

Light sources the temperatures represent
Text description of the Light sources the temperatures represent. (0:27)

Here are some examples of light sources that a color temperature (measured in Kelvin) might represent.

  • 1,000° K - Sunrise
  • 1,900° K - Candle light
  • 2,800° K - Light bulb
  • 3,000° K - Halogen bulb
  • 4,000° K - Fluorescent light
  • 5,500° K - The Sun at noon
  • 7,000° K - Overcast sky
  • 10,000° K - Clear blue sky
Credit: © Penn State is licensed under CC BY-NC-SA 4.0

The ability to see colors properly is another aspect of lighting quality. Objects' colors appear to be different under different types of light. The color rendering index (CRI) scale is used to compare the effect of a light source on the color appearance of its surroundings. A scale of 0 to 100 defines the CRI. A higher CRI means better color rendering, or less color shift.

Instructions: Move the drag button in the center of the picture below to see the difference between low CRI and high CRI.

Factors Affecting the Number of Lamps Required

Instructions: Click on the hot spots below to determine the factors that affect the number of lamps required:

Factors Affecting the Number of Lamps Required.

  • Fixture efficiency: certain fixtures reflect more light than others. Fixtures that are not highly reflective may absorb some light, resulting in less light reaching the user.
  • The effects of light losses from lamp lumen depreciation and dirt accumulation. As lamps age, or when dirt accumulates on the bulb surface, the lumen output from the light bulb decreases. Therefore, newer light bulbs produce more light than older bulbs of the same wattage.
  • The reflectance of surrounding surfaces: bright colors or reflective surfaces painted with glossy texture finishes will appear brighter than a surface with flat finish paint.
  • Lamp lumen output: the efficiency of a bulb increases with wattage. For example, a 40 watt bulb produces 505 lumens, where as a 100 watt bulb (2.5 times the 40 watts) produces 1750 lumens (4.32 times the 505 lumens).
  • Availability of natural light (daylight).
  • Room size and shape.
Credit: Activity © Penn State is licensed under CC BY-NC-SA 4.0 (opens in a new window)
Credit: Image Pennsylvania State University. (2026). Copilot.
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