Everyone knows the basic principles of warm air and cool air – warm air rises, cool air sinks. You can see this in practice when a hot air balloon is filled with heated air and rises. When the air inside the balloon cools, the air becomes dense causing the balloon to lower.

This principle applies to the air inside your home. This results in something called Stack Effect. Here’s how it works and how it affects your home’s performance.

During winter months, indoor air that’s been warmed rises to the upper areas of the house. Due to natural penetration points in the roof of a home (e.g. around electrical penetrations, vents, etc.) this warm air leaks out of the home.

Losing air that you’ve paid to condition affects your wallet – and has an even greater impact. When heated air leaks from the upper level of your home, negative pressure is created in the home. Since air in the home wants to remain in balance, cold outside air is sucked in to the home through penetration points on the lower level (e.g. around windows, electrical outlets, basement box sills, crawl spaces, etc.)

During winter months, warm air inside the home is desired. What do homeowners do? They turn up the HVAC system. This creates a false sense of an efficient home because the heating system overrides any feeling of discomfort.

What about summer? During summer months, stack effect creates a much more uncomfortable living situation.

As the warm inside air rises in a home and escapes through upper level penetration points, warm outside air enters the home through lower penetration points. The home’s HVAC system will run to help cool the air inside the home. Since cool air is dense, the conditioned air will not reach the upper level of the home. This can create an unbearable living situation in the upper level of a home during peak summer months.

If you dread the upper floors of your home during summer months because of hot and uncomfortable air, your home needs air sealing and insulating. Contact us to discuss your home’s summer comfort issues and schedule a free estimate.