Should You Close Crawl Space Vents in the Winter?

Most crawl spaces have vents along their walls. In the past, these vents were thought to create proper airflow and keep the area dry and temperature-controlled. Unfortunately, today, we know that the opposite is true.

Open vents actually allow outside air into the crawl space, making the area under your home feel the same as the area outside. In the winter, this causes issues—and it’s a good idea to seal crawl space vents. We’ll explain why on this page (and what you can do).

• Vent Covers: You can often find these at hardware stores. You attach them directly over the open vents from the outside to reduce airflow, but they won’t keep all the air out.
• Crawl Space Encapsulation: Using different tools (vapor barrier, dehumidifier, foam board insulation, drainage matting, and more), professionals seal the crawl space from the inside and stop all airflow through open vents.

• Higher Energy Bills: Open crawl space vents in the winter allow cold air to collect under your home. This makes your floors cold and causes your heating system to work harder, costing you more money.
• Frozen Pipes: If you have plumbing in your crawl space, freezing winter temperatures may cause the pipes to freeze. Eventually, the water inside them can burst as it freezes and expands.
• Pest Infestations: Bugs and rodents seeking warmth in the winter may find a home in your crawl space. If they get through open vents, they leave behind food waste, feces, and musty odors (all of which you breathe in).
• Wet Insulation: Fiberglass insulation is commonly found in crawl spaces. In the winter, cold air causes the insulation to become frozen or wet, drastically lowering its effectiveness.

If your crawl space has open vents, you need to close them before winter rolls around. Even better, closing open crawl space vents will keep the area dry and safe in any season.

At AquaGuard Foundation Solutions, we keep crawl space vents shut with our industry-leading crawl space encapsulation system. Contact us today to learn more or to schedule a free inspection.