Why buy LED Tubes with a high Power Factor?

In a previous video about important questions to ask before buying your LED tubes, I mentioned the importance of an LED tube having a good power factor. LED Tubes with a low power factor will result in lower actual energy savings and penalties from Eskom. Check this video out or read on for more:

Power Factor is defined simply as the measurement of any electrical device or equipment’s ability to convert electrical current (supplied by dear old Eskom) into useful power output.

From a technical standpoint, power factor is presented as the ratio between Active Power measured in Kilowatts (Kw) to the Apparent Power measured in amperes (kVA). Active power is thus used by an electrical device – in this case an LED tube to generate light. This relationship creates a ratio of anything between 0 and 1 – and just so you know an acceptable power factor ratio is anything above 0.9 so your power factor needs to be high and for some very good reasons related to electrical costs versus actual savings.

Let’s provide an example that most of us can relate to: Imagine a pint of beer versus the amount of froth it has.

Froth does nothing to quench the thirst of its owner – this represents the kVAr (or reactive power or wasted power) and the beer (which does the job of quenching thirst is represented in Kw which is the active power or real useable power). The total beer itself, beer and froth included, represents the kVA or apparent power. The ideal beer that we all expect is one with maximum beer and little froth for satisfaction which would mean a system that is not drawing much kVAr or Reactive Power.

At the end of the day getting a beer with tonnes of froth is likely to piss someone off…

Bottom line is that if you have an LED tube that operates with a low power factor, it will end up drawing more Reactive Power (kVAr) because Eskom has to supply more Apparent Power to meet your working / active power consumption needs measured in kilowatt (kW).

Why this is bad is because Eskom monitors this and will charge you for it in the form of penalties.

LED Tubes with a lower power factor used in industrial or commercial contexts will end up costing you more to run which defeats the whole exercise of installing energy efficient lights in the first place. The reality is that T8 fluorescent tubes have a very good, high power factor of 0.95 or more and so should the LED tubes that you buy to replace them.

There is something called power factor correction which is the process whereby capacitors are installed to improve the low power factor within a power system. But these cost money and are unnecessary when you buy LED tubes with power factors with >0.9 state as this is Eskom’s lowest acceptable minimum for electrical devices and the reactive power they draw. If you are on or above 0.9 power factor then you won’t get charged more.

So bottom line, make sure you know what the power factor is of your LED tubes. Cheaper LED tubes with cheap drivers are likely to have a low power factor so although you might be saving some cash with a discounted tube, you will end up saving a lot less on power because of the penalties you will have to pay for employing a much less energy efficient lamp.