About three years ago we installed a Control4 Home Automation system in Los Angeles near the beach. As part of the installation, we installed around 50 dimmers and 4 keypad dimmers to control most of the lighting in the home. The homeowner preferred the look of the Lutron Radiora2 wireless lighting system to Control4 wireless lighting, so that was the system we installed. At the time we let our clients know of the positives and negatives of each lighting system to make sure they understood the choice they were making– including the dimming types both keypad dimmers were capable of. One of the light fixtures the homeowners were particularly proud of was a “toe-kick” down-light that surrounded the kitchen island and was controlled by a Lutron Keypad dimmer (a keypad dimmer can dim a light and also control other lights via wireless communication). When the keypad dimmer was dimmed to 50%, the toe-kick light provided just enough light to give the Kitchen/Dining Room area a “cool vibe” when the overhead lighting was turned off while the clients entertained.
About six months ago, the toe-kick light stopped working. The homeowners called out the electrician who had installed the light fixtures to troubleshoot the issue. As it turned out, the fixture had some loose wiring inside it and shorted itself out. The electrician called the light manufacturer to get a replacement light fixture and installed it once he received it. The replacement light fixture was LED (the old light fixture was halogen), but the electrician didn’t think much of it during the installation. Unfortunately, when he turned on the new light with the existing keypad dimmer, the light flickered on and off and would not dim. The electrician could not figure out why the next light fixture would not dim with the existing Keypad Dimmer so he called us to help troubleshoot the issue.
We could pretty much tell what the issue was on the phone with the electrician, but confirmed it when we arrived on site. Although the original halogen toe kick light required “forward-phase” dimming to dim the light, the new LED light fixture required “reverse-phase” dimming to dim the light. The Lutron Keypad dimmer was only capable of forward phase dimming so the new light installed was not compatible with the the existing Keypad dimmer. We called the manufacturer of the light fixture directly to see if we could get an exact halogen fixture replacement with the dimming type we could control. Unfortunately the answer we got was that they no longer made the halogen version and the LED version was the only direct replacement. Thus, the only remaining choices for the customer were two (a) find another light fixture that would fit the exact whole size cut out in the kitchen island or (b) put the toe kick on a non-dimming switch. As you could imagine, the client was not excited about either choice and was forced to learn a costly lesson about dimming types for smart-lighting systems.
As mentioned above, there are two basic dimming types in residential lighting. These dimming types are referred to as “forward” and “reverse” phase dimming, and have to do with when a light fixture is turned off and on during each electrical AC sine wave cycle. During forward phase dimming, the light fixture is turned off from the start of each sine wave until its peak at which point it is turned back on. The light fixture then remains on until the sine wave peak changes into a valley at which point it is turned off again. At the bottom of the valley of the sine wave, the light fixture is turned back on until the end of 1 complete sine wave. This sine wave repeats 60 times per second to create the dimming effect you see on the bulb. There is a lot more technical explanation of forward phase dimming, but the explanation above gives you the gist of what is going on. Reverse phase dimming is exactly the opposite of forward phase dimming in regards to when the light fixture is turned on an off during the sine wave cycle. However, just like forward phase dimming, each sine wave is repeated 60 times per second to create the dimming effect you see on a bulb. So the end result of the light fixture is the same in terms of dimming, but how the light fixture goes about getting dimmed for forward phase and reverse phase dimming control is exactly the opposite of each other.
In the lighting world, there is no specific requirement about which light fixtures use what dimming types. Additionally, light manufacturers don’t do a good job of telling you which dimming type their light fixtures require– you have to search for it deep in their spec sheets. Generally speaking, incandescent and halogen light fixtures will be compatible with forward phase dimming and LED lighting fixtures will typically be compatible with reverse phase dimming. However, we are speaking only generally– we have seen many exceptions that are not consistent with these general trends. Thus, unfortunately you can be at risk for installing incompatible dimmers and light fixtures when purchasing a smart-lighting system, a headache nobody wants to have.
The best strategy we feel you can have to combat this uncertainty when buying a smart-lighting system for your home is to buy what is called an “adaptive-phase” dimmer. Although they can be more costly than forward or reverse phase dimmers and cannot handle as much wattage as their forward and reverse phase counterparts, adaptive phase dimmers can dim both forward and reverse phase light fixtures. Further, they can do so automatically when they are first connected to a light fixture, making their setup easy. We would also suggest getting a “configurable keypad” or similar device and separate adaptive phase dimmer for locations where you want to have 5-6 quick access lighting scene push buttons and need to control a local light fixture instead of getting a keypad dimmer that combines these two functions. Although this scenario will be more costly than buying a keypad dimmer upon initial install, you will save yourself from headaches like our clients’ had with there toe kick fixture. Finally, we would suggest that you pay close attention to your Smart Lighting system contractor when he urgently needs to discuss dimming types with you and your electrician as it will ensure a smooth installation and setup for all.
If you would like help in figuring out which smart lighting system would work best for you, or just have questions about smart-lighting in general, give us a call at 855-832-4775 or find us on the web at www.technospeakco.com.
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