Question

does listening songs via earphone consume less battery ?

Answer 1

I think yes it consumes less battery

Answer 2

Yes, listening songs through earphones consumes less battery.

Listening music normally or by loudspeakers have to overcome more with more power of the external unwanted sound whereas listening music through earphones sound directly goes into your ear so it requires less power to overcome all such factors.

Also speaker coil will be large while earphone driver units are comparitively small.If your phone is dual speaker then obviously earphone will consume less power.