What Is The Stack Effect?

The Stack Effect

Stack effect, also known the chimney effect, is a phenomenon that takes place inside our homes every day. It is probably one of the most common reasons why people consider air sealing their property. This is because it affects the quality of air, temperature, and energy efficiency of our home. Here we will explain in detail what the stack effect is all about.

Stack Effect Winter vs Summer

What is Stack Effect?

It refers to the flow of air when it is being pushed or pulled in and out of your home. This phenomenon happens because of the temperature difference between the outdoor climate and the environment inside your home, which is mostly regulated through HVAC systems. During the cold winter days, we want our home to be warm and cozy, for which we light up fireplaces and put our HVAC system in heating mode. During the summer months, we keep the temperature low, making our home fresh and comfortable. This difference in our home and outside environment air temperature gives rise to the stack effect, which pushes and pulls air repeatedly through the attic and crawlspace of our home.

What Happens During Winters?

When winters arrive, they bring harsh and cold weather. To keep yourself warm, you use heaters or switch your HVAC units to heating mode to keep a comfortable temperature inside. Since the cold air outside is relatively dense, it causes the hot air indoors to rise in the upper portion of your home. As the warm air rises, it results in a pulling effect in the lower parts, like the basement and crawl space, enabling cold air to pull up into the home. The cold air pushes the warm air, which escapes to the outside environment through uninsulated areas, mostly attics.

What Happens During Summers?

Something similar, yet in reverse happens in summers. During the hot weather months, you switch on your air conditioning units to fill your home with cool air, making the sweltering, uncomfortable heat bearable. This is where the stack effect begins to take place again. Since cool air is denser compared to the hot air outside, it is pulled down into the lower portion of your home and escapes through the non-air sealed basement. This, in turn, causes hot air outside the house to be pulled in via an uninsulated attic, creating the stack effect in reverse.

Stack Effect

Is the Stack Effect Bad for your Home?

Yes, indeed. Due to the continuous exchange of hot and cold air, the stack effect makes it difficult for your HVAC system to maintain the required temperature, causing it to work harder. Without proper crawlspace and attic insulation, the energy consumption of your HVAC system increases considerably, resulting in higher energy bills and costing your money in maintenance and repair.

Is there a Solution to Mitigate the Stack Effect?

The most effective solution to avoid the stack effect is to air seal and insulate key areas, including the basement and attic. If you invest in getting your home air sealed and insulated, you can benefit from 30-50 percent savings on your utility bills. However, it is recommended to get a home energy audit to evaluate potential areas other than the attic and basement to ensure your home is properly treated.

NEEECO can provide you with professional services and cost-effective solutions to your insulation needs. Contact us today to discuss your needs with our experienced team. As a Mass Save® Partner, NEEECO can offer you no-cost air sealing services courtesy of your utility companies; National Grid and Eversource.

Call (781) 514-5882 or contact us to get started with a no-cost Mass Save® home energy assessment.