Top 6 Reasons to Close Crawl Space Vents

Closing your crawl space vents is a change that can have significant, far-reaching benefits.

As temperatures drop in the winter and fluctuate year-round, unsealed crawl space vents can lead to a host of problems, from increased energy bills to moisture-related issues that can compromise the structural integrity of your home.

By choosing to seal these vents, homeowners can enjoy a range of advantages, including improved energy efficiency, enhanced indoor air quality, and a reduction in the risk of mold and pest infestations.

This article delves into the many benefits associated with sealing your crawl space vents, offering insights into why this simple step is a crucial aspect of home care, not just during the colder months but all year round.

Benefits of Sealing Crawl Space Vents 

Winter is a time when cold air enters the house through openings, and warm indoor air escapes. The air from the outside doesn’t just affect the conditions in your home but also within the crawl space.

The stack effect will keep your floors and walls perpetually cold. And there’s the risk of frozen water lines and burst pipes, the leading cause of flooding in winter. 

Here are some of the benefits. 

1. Curbs Indoor Humidity 

While the winter air is less moist than summer, the uncontrolled airflow through the vents means moisture can build up and cause problems. High indoor humidity is behind many crawl space problems, as you’ll see. 

2. Crawl Space Condensation 

Typical of homes with crawl spaces, condensation will happen. The question isn’t if, but when. Condensation occurs when the cold air flows in and causes the indoor air to give up its moisture. Water droplets will form on your walls and insulation material. 

3. Prevents Wood Rot 

Outside air that flows in unabated can also instigate wood rot, weakening floor joists and girders and rendering them ineffective in supporting your home. Wood rot happens when the wood gets saturated or has 20-29% moisture content. You can stop wood deterioration by sealing the vents. 

4. Better Indoor Air Quality

More than half of the air that gets into your home originates from your crawl space. This air doesn’t just bring in moisture, but all the nasty particles, allergens, mites, and bacteria that float aimlessly in the crawl space atmosphere. When upward-moving air gets into your home, it can cause respiratory health problems. These microorganisms make the air stale, stuffy, and unbreathable. 

5. Prevents Costly Repairs 

When water and mold attack the crawl space, it’s going to weaken your supporting structures and damage insulation. Sealing vents will stop both from ruining your crawl space and compromising your home’s structural integrity. 

6. Improved Energy Efficiency 

Perhaps you haven’t been paying attention to your utility costs in winter. Try monitoring them for the three months of winter, and you’ll realize they are way higher than the rest of the year. Reason? You’re heating the home, but the vented crawl space slows down the rate at which your home heats up. This is another way of saying you’ll run your heater for hours to attain the desired temperatures. 

Seal Crawl Space Vents with Encapsulation

Now that you’re familiar with the benefits of sealing your crawl space vents, let’s explore the best way to achieve this: encapsulation.

Encapsulation goes beyond merely sealing vents; it transforms the crawl space into a closed, controlled environment that guards against moisture, pests, and temperature fluctuations.

Depending on the specific needs of your crawl space, encapsulation can involve the installation of a vapor barrier to prevent moisture intrusion, interior drainage systems to manage water accumulation, a sump pump to expel collected water, and a dehumidifier to maintain optimal humidity levels.

This whole-home strategy not only protects the structural integrity of your home but also contributes to improved air quality and energy efficiency, ensuring a healthier and more comfortable living environment.

Schedule a free inspection today.

Michael Wilcher

Michael Wilcher is the Content Lead at Groundworks, helping us to answer all of our customers biggest questions about foundation repair, basement waterproofing, crawl space encapsulation, and concrete lifting. In his free time, Michael enjoys collecting vinyl records, watching Formula 1 Racing, and reading philosophy. He holds an MPhil from the University of Cambridge.

Related Resources

The Tidewater Region’s Guide to Crawl Space Mold 

Crawl Space Vapor Barriers: What You Need to Know

8 Clear Ways Crawl Space Encapsulation Increases Home Value