Skip to Main Content
covered crawl space vents

Do Closed Crawl Space Vents Provide Moisture Control During Winter?

Crawl space ventilation is a confusing area for some homeowners. Read on to find out whether to open or close them in the winter.

Get a Free Estimate

Crawl space vents are a common feature in most Winston-Salem, NC, homes. For several decades, contractors thought they were necessary to allow air and moisture to move freely from the crawl space. 

However, over the years, it has been proven that these fixtures are actually detrimental to your home. 

They not only allow warm, moisture-laden air from the outside into your crawl space, but they also turn this space into a breeding ground for pests, mold, and mildew. 

covered crawl space vents

How Do Open Vents Affect Your Home? 

During winter, the air in your crawl space is generally warmer than it is outside. Open vents allow the cold outdoor air to enter your crawl space. When this air flows in, it drives up the moisture levels and causes condensation. Both can be damaging to your home. In addition, these conditions promote mold and mildew growth, which pose serious health risks to your loved ones. 

Air from the crawl space gets into your home through the stack effect. It’s a phenomenon with a continuous cycle, and it can create a variety of problems in your household. It brings cold air from the crawl space into your living areas. As this air flows in, it carries with it dust mites, mold spores, and moisture. This cold air also creates cold floors and uncomfortable drafts that ultimately increase your utility bills. Unsealed vents also lead to wet insulation, frozen pipes, and wood rot. 

Should Crawl Space Vents Be Closed? 

Yes, vents should remain closed always. Sealing these fixtures will prevent chilly outdoor air from entering your home and conditioned heat from escaping to the outdoors. The effects of closed crawl space vents in the winter include: 

Preventing Frozen Water Lines 

Closing your vents during the winter months prevents the dry, cold outdoor air from freezing supply lines that run through your crawl space. It also helps to keep snow out of your crawl space. 

Preventing Cold Floors 

During winter, cold outdoor air leaks into your crawl space through open vents, leaving you with cold floors. Closing vents helps to preserve any heat in your crawl space in the winter. This ensures your warm conditioned air doesn’t escape to the outside, keeping your home a little cozier even on the coldest winter days. 

Making Your Home More Energy Efficient 

According to a study by Advanced Energy, homes with closed crawl space vents use up to 15% less energy for conditioning the space. This leaves you with lower utility bills at the end of the month. 

Sealing Crawl Space Vents 

Closing the vents in your crawl space during winter is vital to a healthy, more comfortable home. Although there are many ways to seal crawl space vents, the most effective include: 

Vent Covers 

Another way to close your vents is to have your contractor cover them from the outside with durable, airtight plastic covers. These covers are specially designed to close crawl space vents and keep outside air, water, and pests out of the space. 

Encapsulating the Crawl Space 

Don’t forget to encapsulate your crawl space. Typical encapsulation entails covering the crawl space floor and walls with a thick, durable 20-mil moisture and vapor barrier. This liner will protect your home from moisture, dirt, and radon gas, and it will make your crawl space less hospitable to pests. It’s also a good idea to insulate your crawl space with rigid waterproof panels that won’t fail or harbor pests or mold like typical fiberglass insulation. If you’d like to seal off crawl space vents and encapsulate this space, contact Tar Heel Basement Systems to request a free crawl space inspection. We have the tools and expertise you need to create a dry, clean, and healthy crawl space.

Publish Date:

Last Modified Date:

TarHeel Basement Systems Service Map

Our Locations

Fayetteville Location

3400 Walsh Pky, Suite 220
Fayetteville, NC 28311

Greensboro Location

611 Summit Ave, Suite 5
Greensboro, NC 27405

North Raleigh

208 Millbrook Rd. Suite C
Raleigh, NC 27609

Raleigh / Durham / Chapel Hill Location

3333 Air Park Road
Fuquay-Varina, NC 27526

Wilmington Location

1209 Culbreth Dr., Ste 205
Wilmington, NC 28405

Winston-salem / High Point Location

2910 Griffith Rd
Winston-Salem, NC 27103