Coler Natural Insulation Explains The Drafting Effect
"There are a couple of adverse effects of convection heat transfer. As heat naturally rises, it will rise to the ceiling of a room and ultimately the attic. If there is not an air barrier between the living space and attic space, the heat will be drafted into the attic. A well ventilated attic will allow the heat to escape to the great outdoors. A poorly ventilated attic can cause ice damming and extensive structure damage. The problem is that the heat is allowed into the attic space through convection where it can heat the under side of the roof. This creates a draft effect throughout your house which "pulls" cold air in through cracks around your doors, windows, and walls. An air barrier and insulating material can prevent the drafting effect and condensation problems even when applied directly to the underside of the roof eliminating the need for attic ventilation. This has also been approved by the ICC for spray foam insulations." - Coler Natural Insulation

There is an abundance of GREAT information at and we highly encourage you to go take a look.  When you do remember this, insulation does not just help keep the heat in but also helps keep the ac cooled air in as well.  Insulation is not just for winter problems!

Coler Insulation 1194 Scandia Drive Webster, NY 14580