If the crack is in your ceiling hot air in the attic can draw/suck cold conditioned air out. It happens through a natural principle of science call convection.
For at least the last twenty years or so, the most common way of insulating attics in Minnesota is to use loose-fill insulation – either cellulose or fiberglass. This is a huge improvement over fiberglass batts, because batts are nearly impossible to install in attics and they cost more money. Despite the decline of fiberglass batts in attics, I still find a small section of fiberglass batting used above the attic access panel at about 90% of the homes that I inspect, even on new construction.
I’ve lost count of the number of homes I’ve inspected that have folding stairway built into the hallway or laundry room ceiling. More often than not the folding legs are not trimmed to the correct length or properly secured to Read More
Installing rigid foam on the outside of a house is a great way to double the R-value and eliminate air leaks. Large sheets of foam insulation, screwed and sealed to the walls or roof, can cover or replace conventional sheathing and create a continuous barrier to heat loss or gain—something you don’t get with cavity insulation alone. We wrapped the house in this video with 4 inches of polyisocyanurate in two staggered 2-inch layers. This thickness strikes a balance between ease of installation and maximum R-value. If the foam is any thicker, it’s hard to hit studs when driving screws. Plus, combined with 5-1/2 inches of cellulose in the stud bays, 4 inches of rigid foam brings the wall up to a respectable R-40.