Lighting Retrofit Tips
by Kevin Hooper


Most building owners and operators have carried out or considered a lighting retrofit. For some, the experience has been great, for others, not so much.

Following are a few nuggets borne of experience, and the wisdom that comes from making many mistakes. They are meant to be big-picture tips, purposely avoiding the 'do this and you'll be alright' kind of approach that usually ends up creating a band-aid project.

1. Remember That Lighting is for People

I'm sometimes asked, "How can I save the most money on lighting", to which I sometimes respond 'Turn off all the lights'. They then say, "but then nobody could see". Exactly. We need lighting so people can see - the numbers on your tax return, correct labels on prescriptions, and the client's face in a boardroom.

Each of these tasks requires a certain amount of light, in the right direction, of the right quality, with the right glare control, at the right time. Getting it right requires a thorough understanding of technology and the human vision system. A lighting retrofit may be the only chance you have in the next 20 years to improve the lighting for people - and people cost a lot.

In an office, people can cost more than $300/sq.ft.; in a factory an accident can cost tens of thousands in down time, and a lawsuit can cost millions. In a retail store sales can be more than $700/sq.ft. And how much do we pay for lighting in all these spaces? Maybe one or three dollars at the most per square foot. So if we shave 50 per cent off the lighting bill, but interfere with people's ability to see well, the company's bottom line could easily be red.

2. Educate Yourself

First, the Illuminating Engineering Society of North America (IESNA) sets the recognized standards for lighting. Go to www.iesna.org, order a few books, and do some research. Even better, take the ED-100 Fundamentals of Lighting course and create a framework for all future lighting knowledge.

Second, the National Lighting Bureau (www.NLB.org) provides a wealth of independent case studies which reinforce the people-value side of lighting. And here's the good news, you will find that a project which pays for itself in four years through energy savings, may pay for itself in six months (if designed correctly) through improved productivity, safety, comfort, or sales.

3. View Lighting as a System

The ballast drives the lamp to produce light. A fixture houses the lamp/ballast combination, directs the light, and controls glare. As much as 50 per cent of the light never makes it out of the fixture, but if we didn't use a fixture the glare and aesthetics would be terrible. Heat buildup and lamp shadowing also reduce light output. Light is then reflected and/or absorbed by surfaces around the space. Finally, some of the light reaches the task.

Many retrofit options only address part of the system, such as simply changing lamps and ballasts. Again, greater product and visual system knowledge will allow you to take increasingly larger bites out of power consumption, while maintaining or improving lighting quality. Often a complete redesign is the best option, using an approach called 'task-ambient', where lower overall light levels are provided, but with good task lighting where required.

4. Practical Tips

Be honest, you saw the word 'practical' and skipped straight here, and that's OK.

  • Most metal halide systems can be replaced with much more efficient fluorescent systems, even in manufacturing facilities with ceilings up to 40'
  • New light fixtures are often a great option, as significantly improved fixture efficiency can more than make up for the increased cost.
  • Aesthetics are important (people like to work in pleasant environments.)
  • Seriously consider direct/indirect lighting in any office setting, people will love it.
  • You don't always have to use a reflector to reduce lamps in a fixture, and if you use a reflector, 90 per cent reflective white aluminum costs less than specular (mirror), it's almost as efficient, and distributes the light more evenly.
  • Don't go overboard on occupancy sensors, focus on areas where at least 10 lamps are controlled, and the space is often vacant for periods of at least an hour.
  • Use only proven products i.e. recognized brand names.
  • Use at least 4100K fluorescent lamps; lots of good research points to whiter light being more effective, and use at least an 85 CRI lamp
  • T5 and T5HO technology is slightly less efficient, in general, than T8; however they do provide some good new-design options. You can't effectively retrofit an existing fixture to T5 due to the shorter lamp lengths (46 inches vs 48 inches).
  • Fluorescent electronic ballasts now come in 'super' high efficiency for a low premium, and can be chosen to under-drive or overdrive the lamp to optimize savings and light levels.
  • Always keep maintenance concerns in mind. i.e. don't specify multiple types of 4 foot T8 lamps in one facility, they will get mixed up.
  • Keep control systems simple, or provide robust training. (We once retrofitted a chain of large retail stores, some less than two years old, and every single control relay was bypassed because managers couldn't figure out how to use the system.)
  • Provide a set of detailed design documents for contractors, with all quantities and detailed material specifications. You will save more money doing this work up front and providing it to them than you will ever save by finding a slightly cheaper product.

    Kevin Hooper, P.Eng. is an Electrical Engineer and Journeyman Electrician with over 25 years of industry experience. For the past 10 years he has owned Lighting Solutions Inc., an independent lighting consulting firm based in Calgary, AB, with a primary focus on effective and energy efficient lighting upgrades to existing buildings. Contact: www.Lighting-Solutions-Inc.com
    Ph 403.547.8090.

    First published November 2005

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