As a side note, one of the reasons why cold white LED light bulbs are a thing is because they're a bit more efficient than warmer light colors.
The reason is because they all just have 2 kinds of light emiting diode (LED) junctions inside - red and blue - plus a phosphorus layer on top that smooths those two perfect lightwave color peaks in the wavelength domain into a broader light spectrum, and the blue is more efficient than the red, so lamps with a higher proportion of blue emitters to red emitters - and which hence emit more light towards the blue end of the spectrum (i.e. a colder white) - will emit more light for the same power consuption than those with more red emitters and hence whose light is more towards the red side of the spectrum (i.e. a warmer white).
EDIT: So it turns out part of this which I learned 10 years ago is outdated. The efficiency thing is true but when I went looking for how phosphors (the layer between the LED emitters and the outside, which absorbs the single wavelength light from the LEDs and emits light with different wavelengths) prompted by the points made by another poster, from places like this it turns out that red LED emitters aren't at all used anymore, only UV and blue (whose light the phosphor then converts into light with different spectrum distributions depending on the material of the phosphor). If you search for it a number of recent scientific papers pop up around various such materials.