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Lighting Controls – GREENLIGHT CANADA – Vancouver LED Retrofits

 

Lighting Controls

Should ON-OFF or dimming controls to save even more energy (and money) be added at the time of an LED retrofit?

The answer depends on economics, functions/aesthetics and application. 

Economics

A key issue is that an LED retrofit should already have reduced the energy draw by over 50%. So adding controls is working with a much smaller amount of energy to reduce. If adding controls can save another 50%, this means just 25% of the energy draw before the LED retrofit. When analysing the payback of this, it is important to consider the extra cost of the controls versus the actual energy they will save.

The economic case can be bolstered in the circumstance that there are incentives or rebates provided by an electric utility program for adding such controls, e.g. BC Hydro’s BESI or SHRSP support programs.

Functions/aesthetics versus economics

If the objective is to modernise the functionality of a lighting system by adding dimming control or light colour control, the cost of doing it is measured against the improved ‘utility’ for the user.

Application

Common applications of motion sensors and daylight sensor systems are:

  • to dim lights in parkades and stairwells when there is no one present, and 

  • to turn on exterior lights from dusk to dawn

Dimming controls and light colour controls can also be desirable in classrooms, meeting rooms, office spaces and care facilities. Dimming controls can also be used in high-bay applications in warehouses and retail shops where lights can be dimmed, but not OFF, outside of regular use hours.

Types and functions of controls

There are a wide variety of possible controls devices. These include:

  • Motion sensors that send signals to lighting controllers to switch lights ON and OFF

  • Daylight sensors that provide signals to lighting controllers when there is sufficient light levels for the lights to be turned OFF or to be dimmed.

  • Dimming controls, that can reduce the levels of the lights – as long as the lights are designed to be dimmed. 

  • Controls that can change the colour of lights – as long as the lights have LED chips of all the core colours used to change the colour temperature, e.g. from warm 2700oK to very white 6000oK.

Lighting control systems can combine these sensors and control features.

There are various ways that the controls can provide the necessary signals. These include:

  • Direct wired, by running wires between the control sensors or controllers and the light fixtures – or by the sensors being directly attached to the fixtures

  • Wireless by radio transmission (RF)

  • Wireless by WiFi and Bluetooth connections, using smart phone apps.

Retrofits versus new installs

Retrofitting existing lighting systems can be more difficult than a new install as you have to work with the existing lights and their wiring systems. This can be costly.

Adding motion sensors and daylight sensors can be relatively straight forward as there are systems that can use sensors that communicate wirelessly with load controllers that are able to switch OFF and ON the AC power supply to banks of lights.

Adding dimming control is more complicated, and costly, as older style lights are most often not designed to be dimmed. This can mean having to change the types of bulbs and ballasts in existing fixtures to ones that are able to be dimmed. A major issue with doing this is that the fixtures lose their original safety certifications (e.g. CSA, cULus, cETLus) and are not considered to be legal under safety regulations. The project requires the electrical contractor to take out the necessary permits to undertake this work, and all fixtures need to be re-certified through inspections by designated safety authorities. Against all this cost, it can be cheaper to just replace all the fixtures with new LED fixtures that have the controllability functions desired.

The bottom line 

It is possible to add light controls to existing systems when they are retrofit to LEDs. But it can be very costly. Whether it is wise and economic to do so depends on the objective of doing so – and how it is done. Let Greenlight help. We can provide the analysis of possible technologies and costs to help you make a well-informed judgement.