Crawl Space Vents: Open vs. Closed?

Why do open crawl space vents spell trouble for your entire home?

Air is typically cooler in your crawl space than outside. Once the outside air enters your crawl space and combines with the cooler air, humidity is created. As you can see, combining the two creates moisture problems, which are your crawl space’s greatest foe.

To make matters worse, the warm air that enters your crawl space will rise into the living areas of your home, dragging anything light enough to travel with it. This includes mold spores, dust mites, and the humidity already wreaking havoc in your crawl space. This process is known as the stack effect, and it’s a continuous cycle that will cause various problems for your home and family.

Open crawl space vents invite outside air and its accompanying moisture into your home, directly impacting your energy consumption and bills. This moisture increases the humidity level in your crawl space, leading your heating, ventilation, and air conditioning (HVAC) system to exert more effort to maintain a comfortable climate.

The extra work is due to the energy-intensive process of cooling or heating humid air, which is more challenging than conditioning dry air. In summer, the air conditioning must cool and dehumidify the air, requiring more energy. In winter, heating moist air also demands more power to achieve the same level of warmth, leading to increased utility costs.

Sealing off crawl space vents prevents this influx of moist air, helping to stabilize the crawl space environment and reduce the strain on your HVAC system.

Mold thrives in moist and damp environments, making an open crawl space a perfect breeding ground. When left open, vents introduce exterior air, raising the humidity levels inside the crawl space.

This increased humidity is the key factor in mold proliferation. Mold is not only a structural concern but also poses serious health risks. It can trigger allergic reactions, asthma attacks, and other respiratory issues. By keeping crawl space vents closed, you significantly reduce the moisture required for mold growth, thus safeguarding your home’s structural integrity and the health of its inhabitants.

Wood rot is a fungal decay occurring in timber exposed to moisture for extended periods. Open crawl space vents allow moist air to enter, which can be absorbed by your home’s wood structures. This creates an ideal environment for wood rot fungi to thrive, which can compromise your home’s structural integrity.

Wood rot can be difficult to detect in its early stages, and significant damage may have already occurred by the time it’s noticed. Sealing off crawl space vents helps keep the wood in your crawl space dry, protecting it from rot and extending the lifespan of your home’s foundation and structural elements.

Don’t let the crawl space vents debate keep you from protecting your home. Contact JES to schedule your free, no-obligation inspection today! Our experts are ready to work with you to ensure your crawl space is sealed correctly, contributing to a healthier, more energy-efficient home.