When we are near the fire our bodies feel warm because there is a heat transfer from the campfire to our body. While around us there is air that can transfer heat by convection, air penghulu is a poor heat conductor (isolator). If between a fireplace with us is placed a booster or a curtain, it turns out the warm fire we can not feel again. This means there is no heat coming to our body, because it is blocked by the seal.