We are aware that there are several methods for calculating light output. The measuring unit chosen is determined by a number of variables. It was useful to know how much power was consumed per bulb in industrial settings, therefore light output was measured in watts. This has altered with the increase of LED illumination. But with LED, do we get less lumens per watt?
Why Calculate Lumens?
To illuminate the sometimes quite wide regions in industrial environments, we require several light fixtures. There are several fixtures and numerous lights, which adds up to a lot of power and may significantly increase overhead costs.
The quantity of electrical energy in high intensity discharge bulbs like metal halide or high pressure sodium lamps is so vast that measuring in watts makes sense. Since the wattage utilized corresponds to a certain quantity of light, it aids in deciding which bulb to use for whatever purpose.
The higher efficiency of lights like LEDs allows for substantially lower power use than with HIDs. If you needed the same amount of light from an LED as you would from a 100 W HID, you may only need as little as 20W of power.
How Do Lumens Per Watt Work?
Because of this, LED bulbs need a better mechanism for describing their light output. Lumens per watt is a useful metric since it indicates how many watts are needed to produce the desired quantity of light. A metal halide 400 W HID bulb has an average lumen output of around 34,000. This indicates that it has a lumens per watt (lm/W) rating of 85. The term for this is lumen effectiveness.
Although this is a generalization and there are numerous elements that affect it, an LED has an efficiency of around 140 lm/W. Even so, it is still a lot better than HID.
Not merely the difference between the diodes used in LEDs and the arc-lamp HIDs is a significant additional aspect. Its effectiveness is greatly influenced by the energy consumed in the ballast, which controls electrical surge prevention while turning on HIDs. Since LEDs consume far less power to switch on and sustain light output, they do not need this ballast.
Because of this, lumen effectiveness is just one aspect of the problem. The phrase "overall luminous efficacy" is preferable since it considers other elements like heat loss and energy consumed for the ballast.
Why Do Some HIDs Claim to Produce More Lumens Than LEDs, Then?
The fact that multiple forms of light radiation exist further exacerbates this challenging topic. Different wave lengths are used to measure the energy that lights emit. Only some of these wavelengths are visible to the human eye, making the ones we cannot see completely worthless for our purposes.
HIDs are constrained in the sort of light they can produce, i.e., light that is visible to humans, in addition to having lower lumen effectiveness. LEDs can provide significantly brighter light output while also being more energy-efficient. As a result, they use roughly a third less lumens than HIDs while still producing light of higher quality. Lighting efficiency or sometimes wall-plug efficiency is the term used to describe this.
It's possible that an LED bulb's claim that it emits less lumens than a metal halide lamp is accurate. nonetheless, this is only true inasmuch as it emits fewer lumens overall; nonetheless, these lumens are significantly more useful since they can be seen by the human eye. Although some HIDs claim to produce more lumens, they do not provide the same amount of practical light that LEDs do.
