Energy Efficiency Impactors: the Stack EffectSome causes of lost energy efficiency are a simple fact of physics. One of those is the natural principle that hot air is thin and rises while cold air is dense and sinks. Inside a house, these forces combine to create a phenomenon known as the “stack effect.”

Without positive action to counteract it, this effect continuously works against your efforts to improve energy efficiency and maintain comfortable temperature control.

Here’s how it happens:

  • In summer, your air conditioner produces dense, cold air that sinks downward in the house and seeps out through structural leaks at lower levels. The loss of dense air volume down low creates an indoor pressure differential that sucks thinner hot air accumulating in the attic down through the ceiling. This added heat compromises cooling in living spaces below, causing the A/C to run longer cycles to compensate and consume more electricity.
  • During winter, conversely, heat from the furnace rising inside the house creates a chimney-like force that pulls cold air in through openings in the structure. This influx of dense cold air fills the house from the bottom up, pushing out warm air and raising heating costs.

Certain corrective actions can help neutralize the stack effect and keep indoor temperatures more consistent and cooling/heating costs low.

Here are some steps to take:

  • Pinpoint and seal leaks that allow that allow air exchange with the outdoors, particularly those at the uppermost and lower parts of the structure. For example, make sure the ceiling is well-sealed to prevent attic air intrusion and that cracks and gaps around the foundation or crawl space are also eliminated.
  • Heat energy from the sun helps fuel the stack effect during summer. To reduce its influence, check attic insulation to make sure installed depth meets present Department of Energy recommendations. Also verify that insulation is evenly distributed across the attic floor and there are no gaps. If additional insulation is required, it may be added atop existing layers.

Learn more about the stack effect and how it impacts home energy efficiency by contacting the professionals at Mowery Heating, Cooling and Plumbing.

Our goal is to help educate our customers in Brownsburg, Indiana and surrounding areas about energy and home comfort issues (specific to HVAC systems).