If summer is the right time to open your crawl space vents, winter is the perfect time to close them. Colder weather results in drier air. Dry air and freezing temperatures are the biggest risks for crawl spaces due to the likelihood of freezing pipes.
Those crawl spaces generally have the worst insect and rot damage. If you must close your vents during winter I highly encourage you to do it only when the temperature drops below 32⁰. Otherwise, keep them open when the temperature is consistently above freezing to avoid moisture-related problems.
In the summer, when outdoor humidity is the highest, the foundation vents should be closed to keep the moisture out. In the winter, the idea is to open the vents to push damp air out and allow for circulation.
Closing crawl space vents in the winter is a good idea, especially if you have plumbing or air ducts in the crawl space. Unfortunately, just closing or covering crawl space vents for the winter isn't the cure-all for cold floors, frozen pipes, and pests.
These vents allow outside air to circulate under the floor in summer to prevent the moisture buildup that encourages mildew and rot. In winter, when the air is drier, the vents are closed to reduce the chance that the pipes in the crawl space might freeze.
If summer is the right time to open your crawl space vents, winter is the perfect time to close them. Colder weather results in drier air. Dry air and freezing temperatures are the biggest risks for crawl spaces due to the likelihood of freezing pipes.
However, the right answer is very clear. Your crawl space vents should always be closed and sealed off from the outside elements. Venting your crawl space leads to a variety of issues.
When temperatures drop below the freezing point, water pipes in the crawl space are bound to freeze if the vents remain open. It's a good practice to close off the vents in winter. Doing so prevents the dry, cold winter air from freezing the pipes inside the crawl space.
Study after study suggests that crawl space vents are retrogressive and harmful to your home. You're likely to see their bad sides during summer when the weather is hot and humid. Moisture may accumulate inside and cause you crawl space to get wet. Leaving your crawl space vents open reduces the quality of indoor air.
The Answer is "No", but with Options. The safest and most commonly accepted code for any home is to leave crawlspace vents in place year round. However, there are a few things you can do to help combat those cold winter floors and reduced heating inefficiency due to drafts.
Warm air within the home rises, which causes the vents to draw in air from outside the house. As moisture builds up in the foundation, the air pulled from outside on warm days keeps the humidity at bay and, as a result, keeps everything dry.
Properly seal crawl space vents to keep cold air out and prevent frozen pipes. In addition to closing crawl space vents, a vapor barrier and insulation should be added to protect the crawl space against moisture and temperatures year round.
Foundations are rectangular metal vents that sit just above the dirt line on the exterior of your home. With a little level, they can be pulled open and shut. In tight crawl spaces where air doesn't circulate, a foundation vent allows for some passive airflow, creating cleaner and fresher air.
It can cause the wood to rot, encourage mold growth, ruin your fiberglass insulation and in the end, compromise the structural integrity of your house. Apart from letting moisture in, vents are convenient openings on your house for termites and other pests.
First of all, crawl spaces tend to be cooler by nature. They are generally below-grade, which will be a lower temperature than the inside of the home, especially when the home is heated during the winter.
Vents in a Closed Crawl Space
There has to be a drying action within the space. Generally, the drying comes from the use of conditioned air from the HVAC system or the use of a dehumidifier. With this setup, close and seal your vents.
With all that in mind, is it a good idea to close your basement vents during the warmer months of the year? There's no harm in closing a few basement vents. However, you should make a point of reopening those vents after a day or two of leaving them closed.
People think that if they close vents on the main floor, the system will push more cool air to the upper floor. This strategy often results in reduced cooling performance. If you have a minimal number of vents you should not close any. If you have more vents than you need then perhaps you can shut some.
One vent should be installed for each 8 to 10 feet of foundation wall. Most building codes require 1 square foot of open ventilation area for every 150 square feet of crawlspace. Generally, Automatic Foundation Vents have 50 inches of net free area per vent.
In most cases, a sealed and insulated crawlspace performs better than a vented one. Just about the only time I don't recommend sealing and conditioning is when the house is in a flood prone area and the crawl space frequently sees water entry.
When vents are closed, that pressure builds up, potentially causing damage to the HVAC system. Increased air pressure can create cracks and holes in the ductwork. It can also cause your furnace's heat exchanger to crack. Leave all air vents open to prevent extensive damage to your home's heating system this winter.
If the first floor of your home is colder in the winter months, keep the dampers on the first-floor vents fully open and only partially open the vents on the second floor to force more of the warm air to enter the first-floor areas.
Floor vents were an integral part of the architecture of many older homes, providing an efficient way to circulate air throughout the house. They were often designed to work with other architectural features, such as high ceilings or large windows, to create a comfortable and well-ventilated living space.
Intake vents, such as soffits, are placed lower on the roof, usually under the eaves. Exhaust vents like attic fans, ridge vents are primarily placed at the very top of the roof or the highest pitch where hot air gathers.