What are lumens and how do they relate to choosing led lighting

- May 08, 2019-

The wattage ratings that are used to describe incandescent bulbs were often confused with a measure of the brightness of those bulbs, whereas in reality, wattage is a rating of the amount of the amount of electricity that a light buble consumes. Bulbs with higher wattage ratings are generally brighter than lower wattage-rated bulbs, but wattage is not a direct measure of a bulb’s brightness. For that purpose, you need to refer to a light’s lumen rating. Technically, a "lumen" is the amount of light from a light source that reaches a defined surface area  that is placed at a set distance from the source. If the source generates more light and the defined surface area appears brighter, that source will have a higher lumen rating.

LED lights are rated according to lumens rather than watts because they convert substantially more input electrical energy into light than other types of artificial lighting, and with less dissipation of that energy input into heat. A 40-watt incandescent bulb and a 10-watt LED bulb might both generate 600 lumens, but the incandescent bulb needs 4 times the energy input of the LED bulb for that purpose. As this example suggests, you can use a general rule of thumb to compare incandescent and LED bulbs, namely, an LED bulb requires only one-fourth to one-sixth of the energy input (i.e. wattage) as an incandescent bulb to generate the same amount of light.

If you are looking to simply swap out existing incandescent bulbs with LED’s and you want to continue to think in terms of watts, this rule of thumb will guide you to replace 40- to 60-watt incandescent bulbs with 10-watt LED bulbs, and 75- to 100-watt incandescent bulbs with 15-watt LED’s. A designer or LED lighting technician will be able to give you more targeted guidance that creates lighting which delivers the optimum lumens for specific parts of your office or residence.

You might be using too little lighting in areas of your residence that would benefit from better lighting, such as kitchens or other work areas. Alternately, bedrooms and living spaces will benefit from less lighting that creates a warmer, more comfortable atmosphere. Traditional incandescent bulbs provide little flexibility to control brightness in these areas, but LED lights with a wider range of lumen ratings  will provide for more subtle variations and tighter control to give you the ideal brightness in each area.

LED Lighting consultants will also be able to explain how radiance and illuminance measurements and ratings can give you an even greater sense of the quality and quantity of light that LED bulbs will create in a given space. Your initial task, however, is to understand how to select the right LED bulbs according to their lumens ratings.