Stack Effect

Understanding, mitigating and exploiting the effects of temperature differences within a building

Stack effect is a phenomenon that occurs whenever the temperature inside a building and outside it are different.

Sometimes stack effect can be useful: It contributes to natural ventilation. However, it often has adverse effects that reduce the quality of the occupant experience in a building.

When poorly managed, stack effect can exert strong pressure force on doors, partitions and facades. This pressure causes irritating, costly and dangerous conditions: whistling noises; doors that slam shut or are difficult to open, causing safety issues; migration of odors; uncontrolled energy loss, via loss of conditioned air; and a tendency for elevator doors to jam.

The problem becomes especially pronounced in tall buildings and in designs where the building envelope is not tightly sealed.

Our service

We help you understand how to “design out” stack effect problems in new construction or mitigate problems in existing buildings. With careful consideration, most adverse effects can be avoided or moderated. We can also help determine whether stack-effect ventilation will help or hinder the energy performance of your building.

We have conducted stack effect studies of many buildings—of all types and heights, in all climates, with all manner of issues. We know the full range of problems that can occur and use this experience in all our studies. We can, on the basis of looking at a set of plans for a building, tell immediately whether there is a risk that stack effect issues may occur.

In working to avoid or resolve these issues, one of our key tools is our powerful, custom-built diagnosis software. This tool allows us to model all of the relevant physics very quickly, even for very complex buildings. As a result, we can easily test different options to make sure you get a solution that best balances cost and benefit.