Tar Heel Tip of the Week: Negative Effects of Air Ducts in a Dirt Crawl Space

Monday, March 14th, 2016 by Jaimie Hooker


The air highway in your home has been created by the heating and air conditioning ducts in your dirt crawl space allowing for negative air to escape into the living area above. How? It’s simple– duct leakage.

Air ducts are made of segments of sheet metal, or combinations of sheet metal, duct board and flex duct. Between the sections and at the elbows there are joints which are simply bent, crimped or screwed together. This allows for air to leak out of the connected joints and into the crawl space.

warm humid air enters crawl space vents

As the warmer weather is beginning to become prevalent in our region, homeowners will soon turn on their air conditioning to keep the temperature in their home cool and comfortable.

As the warm humid air enters crawl space vents, where is the first place it will give up its moisture? On the coldest surfaces, right? The coldest surface in your crawl space is likely to be your ducts when the air conditioning is turned on. Water is a conductor, not an insulator. So when a duct is wet, it is warmed by the warm humid air that came through the crawl space vents.

Having open vents and a sweating duct system is a recipe for a higher energy bill during the spring and summer months. Not only will the sweating ducts make your air conditioning system work harder and cause your energy bill to spike, the sweating ducts cause your fiberglass insulation to become soaked, eventually resulting in mold growth in your home’s floor system.

Fixing your crawl space is one home repair that will pay for itself. Tar Heel Basement Systems is in the business of making homes healthier– starting from the ground up! For more information on sealing your crawl space, saving energy costs, and preventing mold growth in your crawl space call our office today.

About the author
Jaimie Hooker is the Assistant Marketing Director at Tar Heel Basement Systems; authoring case studies, technical papers, creating and captioning photo albums and managing website content. She also oversees the organization of video testimonials, shows and events, Jaimie lives in the small town of Madison, NC with her husband, Paul, and 3 year old son, Franklin.