The Stack Effect

Quick Facts:

• The Stack Effect affects every building, but becomes more noticeable the larger a building is.
• In warm weather, air enters from the uppermost floors and flows down. This is reversed in colder weather.
• The Stack Effect can lead to discomfort, reduced lifespan of mechanical systems, and infiltration of unwanted smells.
• Systematically identifying air leakage sources and sealing them will reduce the effects of the Stack Effect.

Addressing the Issues - Offering Solutions

The Stack Effect is a phenomenon that occurs in all types of buildings, but particularly in tall buildings. It materializes when natural air movement enters the lower floors, flows through the entire building structure, and exits through the uppermost floors. In the winter, the Stack Effect is triggered because there’s a distinct difference in air density between the cold, dense outside air, and the warm, less dense inside air. Understandably, this phenomenon is reversed in summer.

In warm climate regions (or for that matter, during a hot summer), air enters a building from the uppermost floors, flows down through the building structure, and finally exits through the lower levels. The downward movement of air is therefore considered a Reverse Stack Effect. While it may be reasonable to equate the problems of Stack Effect with Reverse Stack Effect, there are far more problems in cold climates than warm, simply because of the temperature extremes.

The Stack Effect has negative impacts on high-rises in particular - multi-unit residential buildings, condominiums, and apartment buildings of various heights. Depending on the season, the Stack Effect will impact occupants and/or residents in different ways. By example, when cool air enters the building through the lower levels, residents are cold, so they turn their thermostats up. When heated air naturally rises to the upper level residents, they may open windows for comfort.

Relative to the age of a building, property owners and property managers are constantly dealing with the headaches of Stack Effect. They often describe the phenomenon as a “merry-go-round”. The worst-case situations are older buildings that have the potential for air leakage. Beyond any other issues, these buildings consume tremendous amounts of energy from season to season. As well, the air leakage contributes to undesirable condensation, and compromised air quality.

In tall buildings, the Stack Effect can cause unique problems - everything from elevator doors that don’t open/close properly, to freezing water in the sprinkler system. Unattended, some of the issues can quickly go from a headache to a nightmare. The good news is that Stack Effect can be mitigated, even in existing building structures. It’s a matter of curtailing, or minimizing, the air leakage in the building envelope. And with a professional approach, the results are measurable.   

The professionals at Great Northern Insulation have had excellent outcomes in providing custom solutions for Stack Effect. GNI engineering experts start with a far-reaching building overview and consultation; they continue with a mitigation strategy; and they offer cost effective solutions to address specific problem areas. This may include comprehensive air sealing; high performance insulation; optimized air ventilation; even maximizing operation of the various HVAC systems.  

Importantly, GNI focuses on the specific challenges of a building, and on the singular needs of the building owner. Highly experienced team members assess, recommend, and expedite a solution-based project plan. Specific to Stack Effect issues, there is an emphasis on information collection. This is because sound data makes for better project decisions. Bottom line, GNI will recommend the most cost-efficient remedies, with a view to resolving the requisite building issues.

• GNI Strategic Air Sealing Will Reduce The Impact Of Stack Effect
• Reduce Air Movement And Air Leakage
• Reduce HVAC Energy Costs By Preventing Conditioned Air From Escaping The Building Envelope
• Reduce Occupant Complaints About Temperature Differences
• Reduce Occupant Complaints About Odours From Neighbouring Units

The GNI team will address every problem area in the building envelope - that includes everything from air-barrier issues, to moisture control concerns, to thermal challenges throughout. Given that every building is a unique “system”, it’s important for GNI to determine problem causes, and not just symptoms. This approach allows for a more thorough investigation of the issues, and a more precise forecasting for possible remedies, some of which may involve several steps.

For Great Northern Insulation, competent project management makes for success. Large building or small, GNI provides project oversight that ensures effective remediation, along with successful results. Project recommendations are customized for each client, so that service work is targeted, and client needs are accommodated. For GNI, everything is client-centered – the team is onsite to address Stack Effect, and every effort is made to provide solutions specific to the problems.

For over 35 years, Great Northern Insulation has delivered reliable, superior service to customers across the province. GNI management and installation crews are the finest in the industry. All installed products are manufacturer warrantied; all workmanship is 100% guaranteed; and every team member is committed to project integrity and ethical business practices.