This article series details guidelines for selecting and installing interior lighting to meet the requirements for different building areas.

This article includes excerpts or adaptations from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) , by Steven Bliss, courtesy of Wiley & Sons.or

Guide to Recommended Lighting Levels Indoors

Many factors affect the illumination needed for a specific task. This article discusses lighting recommendations for various indoor areas and includes some RULES of THUMB INTERIOR LIGHTING .

An often overlooked factor is the age of the occupants.

At 60 years old, we need two to three times the light we needed at age 20, and also more shielding and diffusers since older eyes are more sensitive to glare.

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The other main factors in determining lighting requirements are how detailed the work is and the level of contrast and reflectance of the work surface.

Table 5-21 shows the recommended lighting along with common strategies for each type of room. For task lighting, the low numbers in each range represent the light needed for simple tasks with high contrast (reading large black type on white paper).

The high number is for tasks with more detail or lower contrast (reading the newspaper). For very detailed, low-contrast work or for older persons, light levels of 100 footcandles are often needed.

Interior Lighting Rules of Thumb

The illumination level on a surface depends on many factors, including the colors of the room and furnishings and the type of lamp and fixture. High ceilings, dark colors, and diffusers on fixtures all reduce light levels. The commonly used black baffles in recessed lights reduce output by up to 40%.

Tightly focused spots produce much higher light levels than wide floods.

Rules about Distance from Light Source

The distance from the light source is also critical. Doubling the distance to a lamp reduces the lighting level by a factor of four. So moving the light closer to the task is often the simplest way to provide a big boost in lighting levels.

Rule of Thumb for Brightly-Lit Space Needs

As a starting point for design in kitchens, baths, home offices, and other brightly lit spaces, provide at least 2 watts of incandescent light or 3/4-watt of fluorescent light per square foot of floor area. In larger spaces, using multiple fixtures will provide more even lighting and reduce glare.

Downlighting Suggestions

Also, since lighting needs change throughout the day with changes in daylight and usage, it is good to provide flexibility by separately switching groups of lights and adding dimmers. Increase these minimums by 50 to 100% for:

• Valences or other indirect lighting schemes
• Rooms with dark surfaces
• Lighting placed in cathedral ceilings or other high ceilings
• Recessed lighting with diffusers, black baffles, or other light-blocking trim

- - Adapted with permission from Best Practices Guide to Residential Construction (Steve Bliss, J Wiley & Sons) .

Also compare table lighting, task lighting and downlighting

• DOWNLIGHT USES
• SPACING GUIDE for LIGHT FIXTURES
• TABLE TOP LIGHTING
• TASK LIGHTING

...

Continue reading at KITCHEN LIGHTING REQUIREMENTS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Interior Lighting Articles

• LIGHTING, INTERIOR GUIDE - home
• BATHROOM LIGHTING GUIDELINES
• BAYONET BASE BULB TYPES
• BULB & LAMP ABBREVIATIONS & CODES
• BULB & LAMP TYPES GUIDE - home
• BULB COLOR TEMPERATURE COMPRARISONS
• BULB & FIXTURE TYPES for SOFFIT
• CLOSET LIGHTING FIRE SAFETY
• ELECTRIC POWER LOSS / FLICKERING LIGHTS
• FLUORESCENT LIGHT REPAIRS
• KITCHEN LIGHTING REQUIREMENTS
• LED BULB & LIGHTING TYPES
• LIGHTING LEVELS INDOORS, RECOMMENDED
• LUMENS DEFINITION COMPARISON
• RECESSED LIGHT CLEARANCES
• RECESSED LIGHT HOUSINGS GUIDE
• RECESSED & TRACK LIGHT USES
• RECESSED & TRACK LIGHT BULB GUIDE
• RECESSED LIGHT FIXTURE TRIM
• RECESSED SOFFIT or ROOF OVERHANG
• SPACING GUIDE for LIGHT FIXTURES
• TABLE TOP LIGHTING
• TASK LIGHTING
• LIGHTING OVER STAIRS & AT EXITS

Suggested citation for this web page

LIGHTING LEVELS INDOORS, RECOMMENDED at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING LIGHTING

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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