Reading or watching the marketing materials from many lighting and lighting controls vendors its not uncommon to read about extraordinary percentages of energy savings from lighting controls.
There are certainly some very effective and efficient light sources and lighting control systems available today, to be sure, and energy savings as high as 70% and 80% are oft quoted.
However understanding how these proclaimed energy savings from lighting controls systems have been achieved, is paramount in understanding true value from an R.O.I and system payback perspective.
5 Questions to Ask About Energy Savings from Lighting Controls Systems
1. What assumptions have been made?
This is one of the key questions to get a straight answer on. Why?
Imagine for a moment that a building operates 24/7/365 and during this operation all lights are assumed to be on. Yes. Always.
Now, image what the introduction of a simple time based schedule will have if that schedule turns all the lights off at 7pm and on again at 7am.
Yes. 50% energy savings.
Clearly this is not based on reality and it is important to clear the air with the question first and determine what percentage of the savings is attributed to simple time scheduling and what other assumptions have been made.
2. Was there a ‘re-lamping’ portion of the project especially to LED or T5?
This question is especially important for retro-fit applications due to the significant impact on energy savings that LED and even T5 flourescent lamps can have on energy consumption.
The energy efficiency of these LED and T5 lighting technologies compared to older lighting technologies such as T8 (or worse T12) linear flourescent lamps, HID and even tungsten and halogen lamps is far greater.
Omitting this re-lamping undertaking from marketing communications or representing total energy savings as energy savings from lighting controls systems exclusively is a misnomer that skews these numbers.
Understanding the project as a whole and what type of Lighting System has been installed and providing transparency on the system make-up is key.
3. Is it measured or calculated?
Are the numbers based on the actual operation or the proposed operation?
Theory and reality often don’t mix. Why?
Because humans are predictably unpredictable. How they will actually use a space may not align with design expectations.
A good way to determine the energy consumption is to ask for the calculated maximum energy consumption if everything is always on – as a benchmark for energy consumption. This actual discounts most lighting control strategies.
If however the numbers are measured, see the first 2 questions and the following question number 4.
4. During what time period was the evaluation undertaken?
The purpose of this question is again to determine if the numbers are based in the reality of an operational facility, and significantly, one which may have been operating for longer than a week or 2!
Was it a snapshot when everything was set to its lowest possible level to get a number to extrapolate calculated savings?
Was it evaluated over a 12 month period? Was it the 1st 12 months?
Again, accuracy of the data and how it has been collected and evaluated and under what conditions is paramount in the verification.
5. Are the occupants happy with the system and does it add to their productivity or detract from their comfort?
That is, whilst the facility is highly energy efficient and energy savings from lighting controls systems may very well be real, has it been executed to the detriment of the occupants?
If the energy savings from lighting controls systems have been achieved by hamstringing the occupants the net effect to the business is often negative and costs far more than the energy saved is worth.
- Are lighting circuits banked switched based on light levels or times of day providing a jarring change to lighting levels.
- Are the restrooms always dark when entering?
- Are late night workers left in a pools of light with no egress pathways lit?
- Is there any capability to personalise or task tune the lighting for the task at hand?
Hype or Reality?
With the questions in hand and information provided, one can then make an educated decision as to how much of the energy savings from lighting controls systems is hype or reality.
As you can see getting clarity on the reality of energy savings from lighting controls systems and deciphering marketing messages for real numbers can be a complex process. These few simple questions provided can help.
Now its your Turn
Dont agree? Think we are too cynical and we missed out a bunch of assumptions? Is this your reality? Have your say below in the comments.
Image courtesy of Gary Vaynerchuk https://www.garyvaynerchuk.com/