Convection is when warm air rises and leaks out through the roof, drawing outside air into the house at the lower levels. This is the stack effect. There are hundreds of gaps and cracks throughout your home for warm air to escape into the attic. Holes for recessed ceiling lights, gaps around a drop-down attic stairway , wall cavities, and electrical or plumbing outlets are common leak locations. Interior air that leaks out of the house is called exfiltration. How to stop the stack effect is by upgrading your insulation and filling in all the gaps where air can escape such as door, windows, electrical outlets, and through your attic or roof. Losing the air you’ve paid to heat is bad enough, but this escaping air creates a vacuum that pulls in outside air. Cold outside air is sucked into your home through nooks and crannies and all the little openings. In the winter, cold air infiltration usually occurs in lower parts of the house through the basement or crawl space. Spray foam insulation is the only insulation that seals your basement and sub floor. Your crawl space is ripe with musty damp air that is drawn into your home with the stack effect. Closed cell spray foam insulation stops air from penetrating through your floors and all the small cracks. It protects not only from air leakage but from moisture damaging your floor joists and sub floor. Open cell insulation is recommended for your attic and interior walls. It is an open cell foam that allows some air movement while giving your home a high r value in insulation. Closed cell spray foam insulation is recommended for exterior walls and sub floors due to the dense insulating factors. Homeowners will realize a substancial savings in utilities with spray foam insulation due to minimizing the stack effect in your once drafty home.