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Guide to Recommended Lighting Levels for Indoor Areas
Tables & Rules of Thumb for Interior Lighting
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InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.
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, by Steven Bliss, courtesy of Wiley & Sons.
Also see LIGHTING, INTERIOR GUIDE our home page for information about all lighting topics relating to building interior
Green links show where you are. © Copyright 2013 InspectAPedia.com, All Rights Reserved. Author Daniel Friedman.
Guide to Recommended Lighting Levels Indoors
 Many factors affect the illumination needed for a specific
task. 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.
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.
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.
Resources: Manufacturers, Industry Associations, & Sources of Indoor Wall Materials, Flooring, Carpeting, Lighting, Sound Control Materials
Industry & Trade Associations for Lighting and Other Interior Components in buildings
American Lighting Association
www.americanlightingassoc.com
Association of the Wall and Ceiling Industries
www.awci.org
Carpet and Rug Institute (CRI)
www.carpet-rug.org
Drywall Finishing Council
www.dwfc.org
Forest Stewardship Program
www.fscus.org
FloorFacts
www.floorfacts.com
The Gypsum Association
www.gypsum.org
National Oak Flooring Manufacturers Association
(NOFMA)
www.nofma.com
National Wood Flooring Association
www.woodfloors.org
Painting and Decorating Contractors of America
www.pdca.org
Smartwood/Rainforest Alliance
www.smartwood.org
-- Adapted with permission from Best Practices Guide to Residential Construction.
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Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.
- Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
- Steve Bliss's Building Advisor at buildingadvisor.com helps homeowners & contractors plan & complete successful building & remodeling projects: buying land, site work, building design, cost estimating, materials & components, & project management through complete construction. Email: info@buildingadvisor.com
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education.
Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
 The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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- Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
- Recommended books on electrical inspection, electrical wiring, electrical problem diagnosis, and electrical repair can be found in the Electrical Books section of the InspectAPedia Bookstore. (courtesy of Amazon.com)
- * Safety Hazards and Safe Inspection Procedures for Electrical and Home Inspectors at Residential Electric Panels
- Aluminum Wiring Information Website Aluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos, documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
- Ampacity of an Electrical Service: How to determine the electrical service size or ampacity entering a building
- Circuit Breaker, a bad one fails to trip failure at aluminum bus-to-circuit breaker connection - field report and photographs
- Electrical Panels, How to Inspect in buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
- Federal Pacific Electric (FPE) Stab-Lok Circuit Breaker Panel Hazards Website - Latent fire hazards, in-depth authoritative research, documents, advice on Stab-Lok electric panel and circuit breaker failures and what to do when this equipment is found in buildings.
- Lightning Strike Risk Assessment, Protection Systems & Services
- Multi-wire branch circuit inspection and defects
- Rust and Corrosion in Electrical Panels, A Study and Report on Frequency and Cause for Electrical and Home Inspectors at Residential Electric Panels
- "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
- Safety Hazards and Safe Inspection Procedures for Electrical and Home Inspectors at Residential Electric Panels
- "Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
- "How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
- "Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
- "Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
- "How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
- "Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
- "Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
- "Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: I do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
- "Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
- Electrical System & Wiring Hazard Inspection, Detection, Cause, Remedy, Prevention - Main Electrical Page
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