With home construction getting tighter and tighter to prevent heating and cooling loss, this creates a problem for fireplaces. Fresh air is an essential element to wood combustion. Adding the fresh air kit will ensure the fireplace is constantly fed with good fresh air and the fireplace is burning correctly. The fresh air kit should also be highly considered if you are installing the fireplace in a basement. Basements are known to be a negative pressure area of the home. Adding the fresh air kit will help stabilize the pressure and create positive pressure for the fireplace.