How the Stack Effect Impacts Energy Efficiency 

Natural physics, including a simple principle like the stack effect, can have a major effect on your home’s energy efficiency. An efficient HVAC system requires a structure that minimizes heat gain in summer and heat loss in winter. Unfortunately, the stack effect is one of the forces that works against efficient cooling and heating in both seasons.

Here’s what’s going on:

Colder air has greater density and is heavier than warm, buoyant air. During summer, dense cold air produced by your A/C sinks to lower levels of the structure and seeps out through cracks and gaps. This loss of air creates an indoor pressure imbalance that sucks thinner hot air down from the attic into living spaces. The influx of unwanted heat causes your air conditioner to run longer cycles to maintain a cool thermostat setting.

In winter, the process reverses. Hot buoyant air generated by the furnace rises inside the house, creating a chimney-like effect that sucks cold air into the living spaces through openings at lower points in the structure. The volume of more dense cold air “stacks” upward, filling the house and pushing lighter warm air out. As this extra cold air overworks your furnace, energy consumption rises and monthly heating costs increase.

To reduce the stack effect

Its impacts on home comfort and energy efficiency, take these basic steps:

Locate and seal the air leaks that allow air migration into and out of the house. Pay particular attention to sealing cracks and gaps in the ceiling that allow hot attic air to be pulled downward in summer as well as leaks down low around the foundation or into the crawl space that draw cold winter air indoors.

Reduce heat transfer into and out of the house. Heat gain and heat loss are additional factors that fuel the stack effect. Make sure the home has adequate insulation that meets current Department of Energy standards. If more is required, additional layers can be added to existing insulation.

Ask the professionals at Rinaldi’s Energy Solutions for more suggestions to counteract the stack effect and increase home energy efficiency.