healthy house institute

4 Free HHI Books:

Creating a Healthy Household, The Healthy House Answer Book, Healthy Home Building, The Healthy House 4th Edition
Your email will only be used as described in our Privacy Policy

Follow us on Twitter



Proud Supporter of:




The Latest LED Lighting Standards: What Is R9 & Why Does It Matter?

By Michael Bruce

Since the conception of LED lighting, the industry has made great strides to improve the color quality of the light source. Today, color quality is an important consideration when evaluating LED lighting for residential and light commercial applications. A color-rendering index (CRI) for LED in the 80s is widely accepted as a good quality color performance, with Energy Star requiring a minimum of 80 for indoor fixtures. Recent developments in LED technology have allowed for efficient solutions to be available with CRIs in the 90s – bringing the color rendering of LEDs much closer to incandescent lamps – the best color rendering electric light source. But it does not tell the entire story.


article continues below ↓

We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.

To elaborate, the CRI metric was broken down into 14 color ranges. However, the common CRI (referenced in this article and sometimes known as Ra) only covers the average of the R1 through R8 color references, which are pastel color variations that became popular back in the 1960s. There are six additional color references that were not factored into that CRI, including one that is critical to quality illumination and color rendering – R9.

Since R1 through R8 are pastel, they are red deficient. Therefore, a high CRI (for example, 93) paired with a high R9 delivers a brilliant, more accurate display of color by enhancing the red hue.

High CRI Lighting

High CRI lighting comes in many shapes and sizes. Some LED modules feature:

  • An increased color-rendering index (e.g., 93) that delivers better color in both 2700K and 3000K, rendering colors nearly as natural and true as daylighting
  • A more "universal" fit, and broad and even distribution of light
  • 4-inch, 5-inch, 6-inch or other aperture sizes
  • ENERGY STAR® rating
  • 45+ years of lighting based on 50,000 hours at 3 hours per day.


Why does this matter? Consider our everyday lives. Whether people are admiring artwork for home décor, or nurses are assessing skin color of residents in assisted living communities, the strength of the R9 value is an important factor because the color red is prevalent for the eye to interpret more pure colors. It shows a more accurate representation of the actual color. The ability to improve the perception of color by manipulating the R9 value enhances the visual appearance of objects.

R9 is recognized as such a critical value that California is requiring it as part of its new Title 24 codes and regulations. High R9 factors are now mandatory when illuminating new residential and light commercial indoor applications with LED lighting. The new standard provides all builders and contractors the opportunity to make a visual lighting improvement for residential and light commercial projects.

Whether end-users are selecting fresh meat or tomatoes in the grocery store, or trying to avoid selecting navy blue socks instead of black socks, incorporating high color rendering factors will provide the best opportunity to see accurate and vibrant colors.


HHI Error Correction Policy

HHI is committed to accuracy of content and correcting information that is incomplete or inaccurate. With our broad scope of coverage of healthful indoor environments, and desire to rapidly publish info to benefit the community, mistakes are inevitable. HHI has established an error correction policy to welcome corrections or enhancements to our information. Please help us improve the quality of our content by contacting with corrections or suggestions for improvement. Each contact will receive a respectful reply.

The Healthy House Institute (HHI), a for-profit educational LLC, provides the information on as a free service to the public. The intent is to disseminate accurate, verified and science-based information on creating healthy home environments.


While an effort is made to ensure the quality of the content and credibility of sources listed on this site, HHI provides no warranty - expressed or implied - and assumes no legal liability for the accuracy, completeness, or usefulness of any information, product or process disclosed on or in conjunction with the site. The views and opinions of the authors or originators expressed herein do not necessarily state or reflect those of HHI: its principals, executives, Board members, advisors or affiliates.

The Latest LED Lighting Standards: What Is R9 & Why Does It Matter?:  Created on August 27th, 2014.  Last Modified on August 27th, 2014


We do not strictly control Google ad content. If you believe any Google ad is inappropriate, please email us directly here.



Information provided by The Healthy House Institute is designed to support, not to replace the relationship between patient/physician or other qualified healthcare provider.

Education Partners



Popular Topics: Air Cleaners & Air Purifiers | Allergies & Asthma | Energy Efficiency & Energy Savings | Healthy Homes | Green Building
Green Cleaning | Green Homes | Green Living | Green Remodeling | Indoor Air Quality | Water Filters | Water Quality

© 2006-2018 The Healthy House Institute, LLC.


About The Healthy House Institute | Contact HHI | HHI News & Media | Linking Resources | Advertising Info | Privacy Policy | Legal Disclaimer


HHI Info