Due to the different ways they operate, dimmable LED light bulbs may not be fully compatible with dimmer switches designed for incandescent bulbs. LED-specific dimmer switches offer a solution.
Dimmable incandescent bulbs could be dimmed by simply reducing the power that is passed through the bulb, reducing the light (and heat) that it emits. This is not how dimmable LED bulbs work, however. When they are dimmed, they are switch on and off at such a high frequency that it doesn't look like a flicker, but like a dimming of the light. The more the bulb is dimmed, the longer the bulb is off for with each rapid cycle.
If you use a dimmable LED bulb with an existing dimmer switch, you may find that it doesn't function correctly, and instead just flickers uncomfortably. The bulb itself may even stop working completely. Installing the correct type of LED dimmer switch will prevent that from happening.