There are various terms used in the lighting industry, some cause confusion, some help clarify. Below are some of the more common terms with simple, layman definitions provided below.
More in-depth articles on a variety of topics discussed in this overview are also available and/or will be available in the future. If you have any comments or questions, you can email them to firstname.lastname@example.org and include your basic contact information including full name, phone number and the state you reside in.
Lumens – this is the amount of light provided by the light source. While we all used to talk in terms of watts, we now need to talk in lumens. Since LED light sources use so much less energy, and watts are a measure of energy usage, they are not comparable. So lumens help level the playing field in terms of trying to understand how much light you will get. Lumens measures can follow some simple guidelines:
- 500-750 lumens – good level of light, works for recess on 8 or 9 ft ceiling
- 800-1000 lumens – better level of light for 10 ft ceilings
- (My standard is to have a minimum of 900 lumens form my recess general downlighting)v
- Over 1000 lumens – generally for specific lighting needs including very high ceilings, specialty accents and other applications
Watts – this is a measure of energy usage. We all got used to talking in terms of watts as incandescent lamps were generally consistent. Watts do not tell us what our lumen or light output is though. Since LED can be 80% less energy, the lighting industry has agreed to begin talking in terms of lumens. This measure provides a more consistent (though not perfect) measure of the light output. Since the fixture type, design and other design characteristics can impact the final lighting results, lumens is not the only information needed, but it is a good start. And it does allow the end user to compare similar lightbulbs when comparing lumens of each model.Foot-candles – this is a measurement of light on a surface. This is generally a technical term and most end users are not familiar with the definition nor should they try to be. Leave this word for the techies.Glare – in simple terms glare is bad when it comes to lighting. So watch for fixture designs and try to always select fixtures that reduce, minimize or eliminate glare for the end user audience.
Color temp – this can vary from 2700K to 3500K for most residential applications. The K color can be lower or higher than this but in generally, the vast bulk of residential lighting products are in the 2700-3500K range. Since most LED lighting does not warm as it is dimmed (unlike traditional incandescent lighting sources) your color selection is even more important today.
2700K is warm, some call “orange or yellow” vs white 3000K or 3500K. When trying to select the correct color for your residential application, 2700K is best for traditional homes desiring a traditional feel and includes warm colors throughout. 3000K is a white light and works better for a more transitional or modern style home, especially when lots of whites and grey tones are used. Five years ago, there was not a choice, everything was generally 2700K. Now, about 50% of my clients are selecting 3000K. I find the use of 3500K in residential applications a very rare need. See examples below…
Test to be sure before you commit to your final color choice. In many cases, you cannot change color after selection without substantial cost and hassle.
More terms and definitions will be rolled out over time. If you have a particular term that confuses you, please email me and I will see about adding it to assist others.