I have a ballast in my bedroom with three 60 watt led lights in it. The switch they are connected to is a brand new Lutron dimmer specifically made to work with led lights. The hissing is constant even when the lights are not dimmed, but it seems to get slightly louder when dimmed. I switched out the old dimmer to the Lutron in hopes it would stop. Their use to be a ceiling fan connected here. So I've come to the conclusion that there is just way to much power running to the lights hence the sound. Does this sound accurate? How would i reduce the power running to it to test my hypothesis?

2 Answers 2


You have two options, get rid of the dimmer or try different LED bulbs. All LED bulbs hiss when on a dimmer, some bulbs hiss much louder that others. A led compatible dimmer will help reduce the amount of hiss but it will never get rid of it.

Here is an article that compares a couple of different led bulbs and dimmer switches. It looks at the quality of light and the amount of buzz each bulb makes with different types of dimmers. http://www.cnet.com/news/which-led-light-bulbs-are-best-for-dimming/

  • I see. So even if they're are not actually being dimmed they will still hiss? Why exactly do they hiss? May 7, 2015 at 22:06
  • 2
    It depends on the dimmer if it will hiss when it is turned on full. Some do, some don't (really, some dimmers cheat and never go full on but just slightly dims when full on). As for the exact cause of the buzz from the lights, I can't answer that but I do know it is caused by the electronics used to convert the chopped AC wave form to a level DC current. Dimmers work by quickly (120 times a second) turning the power on and off, the lower settings keep the light off longer before turning it back on.
    – diceless
    May 8, 2015 at 3:46

Some combination of the switch, ballast and lights you have may not be 100% compatible.

Take a look at Lutron's LED Selection Tool. You can pick the dimmer and the lights you have and then you can pull up a PDF report for the testing they have done.

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