One question that we hear a lot when talking about lighting is “What is the difference between Lumen and Lux?” That’s a great question, and it’s something you need to get your head around when selecting light fixtures.
The chart at right is an example of the information that you’ll find in our lighting catalog for each of our light fixtures. All of the Häfele Loox LED lighting fixtures have a lumen rating that indicates the light output at the fixture, and then this chart explains the Lux levels that you can expect at various distances from the fixture. You’ll notice that the “warm” colored 3200 K fixture will produce a lux level of 70 lx at a distance of 500 mm, (roughly 19″).
One of the best ways to explain this concept is to think about your shower head. All modern shower heads in the USA dispense a maximum of 2.5 gallons per minute. If you held a bucket up to the fixture so that you catch every drop of water, you’d collect 2.5 gallons in about a minute. With a light fixture the lumen rating is a measurement of ALL of the light produced by the fixture.
Now, imagine moving that bucket to the floor of the shower. How much water would it collect in a minute? The fixture is still dispensing 2.5 gallons, but because the bucket is further from the source any one spot below is going to receive less water. As it relates to lighting, this measurement is called Lux.
So in a kitchen, if I know that I want 50 lx of light on my work surfaces, and that I have cabinets in one part of my kitchen that are 18″ above the counter, and 30″ over the counter in another area, I’m going to need two different fixtures with different light outputs, or I’m going to need more of them where the distance is greater.
Your Häfele rep who can walk you through this, or can even get you connected with a lighting designer who can help you achieve the results you desire.