All fireplaces have a smoke chamber behind and a lobby that goes to the left or to the right. It is so rare that it will go straight. Having a huge lovely fireplace in your home, use a large Chimella to perfectly fit in so you can feel the warmth of it. Insert the Chimella inside and tighten it up. It will only take 5 seconds to install it. The air pressure changes in the house and it can’t come into your fireplace. It will definitely keep the heat in your house.