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March 20, 2018
Stack effect occurs in most homes as a result of pressure differences and flaws in the home’s building envelope. If you’re not careful, it can significantly reduce your home comfort.
How It Works
Warm indoor air rises because warm air is less dense than cold air.
Warm air enters the attic and escapes through air leaks.
A vacuum effect pulls cold outdoor air in through lower areas of the home.
The process repeats as indoor air continues to be heated.
During the summer, reverse stack effect occurs. Cool indoor air escapes through lower areas of the home and warm outdoor air gets drawn in through the attic.
Stack effect can cause a number of home comfort and efficiency issues:
Cold drafts near exterior walls
Cold floors above the crawl space
Heating system that always runs
Unusually high energy bills
What You Can Do
Stack effect is largely caused by air leaks in a home’s building envelope. That makes air sealing the number-one way to combat stack effect. A number of related upgrades can also reduce stack effect.
Seal all air leaks
Insulate as needed
Ensure proper ventilation
Maintain HVAC equipment