Yin is the feminine energy, it symbolizes cold, receptivity, calmness and softness.

Yang is the male energy, it means power, heat, action and creativity.

Chemneys produce heat, they are "Yang" elements and produce positive energy if well .

For example, dark colors are "yin" and should be tempered by light colors "yang".

This picture shows a yang color house and puting a "darker" painting on the walls harmonizes the yin energy that circulates in it.