Energy technologies: Lighting

Lighting has a number of common energy saving options. With Emsol, you should be able to achieve savings of between 40% to 90% in most lighting applications.



With LED technology becoming main stream since 2014, this has opened up many energy saving options. At industrial sites, lighting energy is typically 5%-10% of total electricity use. In many commercial buildings and offices, lighting energy is 25%-40% of total energy use.

One of the challenges with making large energy savings from lighting projects has been the difficulty in switching off lights when not needed. Many lights at industrial sites, or in high bay buildings, are being left on because these lights have a re-strike time (meaning once they are switched off they cannot be switched back on again within approximately seven minutes). Therefore, people tend to leave them on in case the room needs to be reoccupied quickly.

These types of lights are metal halide, sodium, or mercury vapour (HID, high intensity discharge).


Using LED technology instead of HID will halve electricity demand, increase light level up to 30% and allow the lights to be switched off every time the last person walks out of a room.

Where halogen or incandescent lamps exist, replacing these with LED or fluorescent technology should be a high priority for saving 40%-80% energy. Incandescent technologies waste most of the energy because they put out more heat than light energy. This is the reason these lamps are too hot to touch! Note that incandescent lamps are needed in some aesthetic applications if an LED equivalent cannot be found.

Where fluorescent light fittings exist, replacing these with LED may still save up to 20% in energy, but there will be larger cost savings from maintenance of the lighting system. An LED light lasts more than twice the time of a fluorescent tube. LEDs continuously fade in light level from new; the life of an LED is typically measured when its light output is 70% of its light output when new. Replacing old fluorescent lighting systems with LED will also restore light levels to what is required.

The quickest payback from lighting energy savings is controlling lights to switch off when not needed. This can save 50% energy at the cost of educating people or using sensor control switches. Automatic switches can use occupancy sensors or daylight level sensors or both.

A rule of thumb is to switch off lights if vacating a room for more than 10 minutes.


The effect on energy use from switching lights on and off every 10 or more minutes is insignificant. Additional energy use when a light is switched on lasts for less than 0.1 of a second!




Some of the more effective tips for saving energy with lighting include:

  1. Switch off lights when vacating a room for more than ten minutes.
  2. Install occupancy sensor switches to switch off lights.
  3. Install light level sensor switches to switch off lights where natural light is available.
  4. Replace lights with quality LED technology.
  5. Replace new or efficient fluorescent tubes (or fittings) with LED at the end of tube life.
  6. Clean light diffusers regularly in dusty environments.
  7. Replace old opaque diffusers with new diffusers.


EECA lighting 


Case Studies

LED lighting case study