There is no greater ‘workhorse’ in commercial lighting than the all too common fluorescent grid unit – deployed in a typical suspended ceiling. So it is logical that the replacement of these fixtures offers the greatest savings for office based companies. The LED panel replacement has been on the scene for a while and has constantly improved over time in terms of light quality and has been tumbling in price!
So there has never been a better time for your clients to opt for LED panel lighting to enjoy the substantial energy savings available, but do you choose back lit or edge lit? How do you match the colour temperatures of the existing units and is ‘glare’ a factor? All will be revealed!
Switching to Save
There are very compelling reasons to switch to LED Panels; with a payback of around 2 years or less depending on installation and that is before you truly consider the impact abandoning the overheads of tube replacement, disposal costs and other maintenance charges associated with the old fluorescent units. After all 600×600 LED panels are cost effective and will continue to be – given the trend in increased energy prices.
Replacing a unit
Traditional benchmark: typically 600 x 600mm ceiling tile sized luminaire would use 4 x 18W fluorescent T8 lamps – 72W with an output of 3240 lumens that will drain 88W of power including the power consumption of the ballast.
Backlit or edgelit?: There is a difference and depending on how and where the LED chips are positioned.
Edgelit has LED chips around the perimeter of the fitting and uses an acrylic or polycarbonate diffuser to carry the light across the fitting and then out.
Pro – will be a shallow depth panel,
Con – light is having to be redirected so arguably performs less efficiently. Cheap models can have a faint shadow around the perimeter where the light guiding plate isn’t positioned correctly. LEDs have to be driven harder to achieve the same amount of light produced compared to a backlit panel.
Backlit logically makes more sense as the light is immediately travelling in the right direction.
Pro – more efficient use of light and more uniform diffusion.
Con – currently needs about 80mm depth but that is still acceptable in the majority of cases.
Colour temperature: 4000K is the standard colour of white and I value the available option to choose 3000K warm white for some interior applications. Remember that a colder 4000K fitting will deliver a little more light for the same power used compared to a 3000K fitting.
CRI: colour renditioning must be over 80 RA.
Colour Tuning: LED panels can offer the opportunity to control and change the colour temperature, to engage with our circadian rhythm.
IP rating: Protection against the ingress of moisture. Many panels are IP44 as standard and you can get IP65 if jet cleaning is required.
Dimmable: Choose carefully if you want to dim the fitting and how it will be controlled? A panel with external driver will allow you to reselect a driver to suit the requirement of the building.
Glare factor (UGR): This is a bit of a poser in terms of a question. As office dwellers, we are used to traditional fluorescent fixtures – with their lamps tucked up deep within the fitting and shrouded by louvres to direct the light. A LED panel with a diffuser that is flush with the ceiling will surely produce more glare?
As a question it is actually not that simple to answer as a glare factor is calculated by comparing the background illumination of a room with the fitting. In reality the amount of fittings in a room will vary. So glare can be quantified by using a standardised room but it will vary upon application. The upshot is flush diffusers of LED panels deliver light in an acceptable way as long as the right amount of fittings are used for a given application.
Efficiency: there is much less light lost within a LED luminaire compared to fluorescent. A fluro tube sends light in all directions and the optics of the fitting collect the light and direct it back out – up to 40% of the light can be lost. LEDs are very directional so the light can be delivered more efficiently
Lumens per Watt – Lm/W – efficiency – measures how much power is being used to deliver the amount of light created. We should be looking at around 80 lm/w upwards. Example – a 35W panel delivering 3200 lumens of light has an efficiency of approx 90 lm/W – whereas the traditional fluorescent fixture mentioned above would be 37 lm/w
Fire: Something easily forgotten but check to see if a chosen panel can be used in escape routes – Part B of the building regulations referring to the spread of fire within a building. Part B separates materials into 2 categories of acceptable or unacceptable because of the risk of burning and dripping flaming material onto occupants. Acrylic diffusers will not pass for emergency escape routes – polycarbonate will meet the standard.
Check the type of grid ceiling – some panels will not fit into concealed grid ceilings – the type of grid ceiling where you only see the 600×600 tile.
Switching to LED is the very best advice you can offer to a client in terms of cost savings. We have tested a very wide range of highly reliable yet keen priced panels that are readily available.
Call us and we will be happy to help.
Diagram and fixture pictures are Integral LED