Warm dimming LED downlights, or dim-to-warm LED downlights, warm glow dimming LED downlights, are dimmable LED luminaires capable of replicating the color shift behavior of incandescent lamps as they are dimmed to a lower intensity. It is well-known that thermal radiators glows white hot when they are heated at full rated power. At full brightness the light produced by incandescent lamps has a color temperature falling within the range of 2700 K to 3300 K. However, when incandescent lamps are dimmed to produce a lower light output, the color temperature changes to as low as 1700 K. To the human eye, the light produced by incandescent lamps over the course of dimming appears to go from the neutral shade of white to orange-ish which is approximately the color of a match flame or light from the setting sun.

Naturally, the inherent characteristic of incandescent lamps has developed a preference for the cozy shift from yellow to red tones. Warm glow dimming has been seen as a feature indispensable to create a cozy and intimate environment in restaurants, hotels, theaters, high-end residences, etc. LEDs, however, have a constant correlated color temperature (CCT) across the entire dimming range. The dim-to-warm technology was developed to give LED systems the dimming characteristics of incandescent lamps, with all of the energy saving and performance benefits of LED lighting.

Warm dimming LED downlights incorporate a minimum of two different LED primaries, with their light mixed in different proportions to enable changes in CCT over the course of dimming. Dim-to-warm LED downlights are single-channel systems which require only one control signal to adjust both color and intensity. This is in contrast to tunable white LED downlights which operate on separate control signals to independently adjust the color temperature and intensity of light.