By Stan Walerczyk
As a follow up to this article, we will discuss new information on soft savings to help end-customers approve lighting retrofit projects, even if the hard savings, including energy savings, rebates and reduced maintenance, are not that great.
For a quick summary of my previous column, it stated that although we can still save about 50% of the wattage on lighting retrofits, there is much less wattage savings than with previous retrofits.
I use a certain feasibility table, or a variation of it, quite often. I typically create one for the most common fixture type in a facility and go over the pros and cons of each option with the client. There are six financial columns and the most important one is long-term benefit comprehensive. Payback is not the best financial tool, because it does not include any of the benefits after the payback period, and those benefits can be substantial. The most important columns in this table (highlighted in purple) are the annual maintenance savings, improved worker productivity savings, and the sum of both of them.
Let’s look and parts and labor maintenance savings. Option A only has a $2 benefit per year, because the proposed lamps have a longer life, especially with a program start ballast, but the quantity of six lamps in the room is kept. Maintenance savings for the other fluorescent options is increased, because only two lamps are in the room and they have an extended life rating, especially with the program start ballasts. The LED troffer kits have highest maintenance savings, because most of them will last 100,000 hours.
Now we can examine the worker productivity column. Option A has the lowest dollar amount because the parabolic louvers are kept, and they are not very good, due to the dreaded “cave effect,” often insufficient vertical light levels and overhead glare. The reason for the $2 is that the CRI went up from 75 – 78 to 80 – 85. All the other options have much higher worker productivity benefits. For example, $500 is based on a $50,000 per year office worker, wasting 5 less minutes per day, which is 1% of an eight-hour shift. The worker productivity numbers really increase with both suspended indirect/direct fixtures with task tunable (dimming and Kelvin changing) task lights or tunable LED troffer kits with tunable task lights. For example, $3000 is based on a $50,000 per year office worker wasting 30 minutes less per day, which is 6% of an eight-hour shift or a $100,000 per year office worker wasting 15 minutes less per day, which is 3% of an eight-hour shift.
Tunable lights are very good for Human Centric Lighting, which can improve circadian rhythms, alertness, mood, perception, performance, sleep and general wellbeing.
Although option A has the best straight payback, it has the worst comprehensive long-term benefit by far.
For this application, none of my clients selected option A. In the past, the most common preferences were B1 in most places and C1 in high management or ownership offices. Now it is transferring to LED troffer kits, especially tunable ones. Hopefully, there will be tunable LED suspended indirect/direct fixtures soon.
This approach should help distributors and contractors increase sales and profits, while providing improved lighting solutions. Lighting should no longer be considered a commodity.
If you would like the excel version of the table above, please email Stan at stan@lightingwizards.com.
Tagged with circadian rhythms, Exclusive Feature, lighting, tED