Most homes have a crawl space which is an area around two to three feet high located between the first floor and the ground. The purpose of the crawl space is to allow access to plumbing and electrical lines, as well as to provide a bit of extra insulation and support for the first floor.
Some homeowners prefer sealing off crawl space vents throughout the year also known as crawl space encapsulation to prevent termites in the summer, cold air in the winter, or moisture and humidity all year long. However, others believe it is necessary to open and close the crawl space vents according to the season.
There is no definitive answer as to when you should open or close your crawl space vents. However, there are a few things to consider which can help you make a decision.
What are crawl space vents?
Crawl space vents are small openings in the foundation of your home, allowing the movement and circulation of air in and out of the crawlspace. The vents are usually located around the perimeter of the crawlspace. Crawl space vents help to keep the area dry by allowing moisture to escape, and they also help to regulate the temperature. These vents are covered with a screen, wire nets, metal grids, or slats to allow air movement and keep out insects and other pests.
Should you consider sealing off your crawl space vents:
The process of closing a crawl space is referred to as crawl space encapsulation. Encapsulated crawl spaces are isolated from the outside environment and upper living spaces.
Recent research has shown that homes with sealed crawl spaces are more energy efficient. Sealing off your crawlspace helps to reduce your heating and cooling bills by as much as 30%. It also helps to keep the area drier and discourage condensation and moisture buildup making the area mildew, mold and corrosion-free. A dry crawl space reduces the chance of wood decay and structural damage.
In addition, crawl space encapsulation will help reduce the stack effect and improve the indoor air quality of your home.
What is the stack effect?
The air in the crawlspace is cooler than the outside air. As the outside air enters the crawl space, it combines with the cooler air and creates moisture problems. Also, as the air rises in the home, it transports moisture, mold spores, and other pollutants from the crawlspace up into the living areas of your home. This natural convection is called the stack effect. Breathing polluted air can cause or aggravate allergies, respiratory problems, and other health issues.However, as air in crawl spaces is cooler, it may remain moist due to ample humidity. Thus despite sealing the crawl space vent, it may create an ideal environment for mold and mildew to grow. So, If you do decide on crawl space encapsulation, make sure that you:
- Seal the crawl space with airtight vent covers made from sheet plastic or heavy-duty PVC that does not rot
- Install a vapor barrier on the ground
- Install a sump pump
- Install a dehumidifier in the crawl space
- Check the area regularly for any signs of moisture or water problems
- Make sure that the humidity level in the crawl space is no more than 50%
But remember, if you have a gas-fired water heater or furnace in the crawlspace, sealing off the vents can create a risk of carbon monoxide poisoning.
Should you consider seasonal opening and closing of your crawl space vents:
One of the main things to consider when deciding whether to open or close your crawl space vents is your area's climate and weather patterns.
According to building experts and strict building codes, opening your crawl space vents during the summer months may be beneficial to allow outside air to circulate under the floor and prevent mold growth. On the other hand, you can seal off the vents throughout winter to keep cold air out to prevent the pipes from freezing. Also, it helps to keep the wet air out during the rainy season.
Opening and closing crawl space vents during summer and winter also help to prevent moisture buildup and condensation in the crawlspace.
However, opening crawl spaces can be a bad idea, especially in areas with humid climates. The warm, moist air will enter the crawl space and condense on the cooler surfaces, providing an ideal environment for mold spores to grow and multiply. Musty odors and bouncy floors are also common signs of a humid crawl space, leading to foundation damage. Thus, you end up spending money on foundation repairs.
Also, in areas where humidity is low in winters, closing the crawl space vent keeps the dry air out, leads to problems like wood decay, and encourages pests like carpenter ants and termites.
Installing a dehumidifier can control humidity all year round, keeping the crawlspace cooler in summer and warmer in winter. Thus, you need not worry about opening or closing the vents each season.
Conclusion:
All in all, whether to open or close crawl space vents should be made on a case-by-case basis, depending on your area's climate and weather conditions. If you're unsure, it's always best to consult a professional contractor who can assess your home and make recommendations for crawl space repair based on your specific needs.
