Why do I need crawl space ventilation?
The presence of moisture is what leads to mold, which can be bad for your health and costly to remove. According to the Environmental Protection Agency, the way to control mold is to control moisture. Proper ventilation exhausts moisture from the crawl space and replaces it with fresh, drier air.
Is ventilation required for vented and encapsulated crawl spaces?
YES - The International Residential Building Code Section R408 requires ventilation for both vented and unvented crawl spaces.
Vented Crawl Spaces: R408.1 Ventilation. The under-floor space between the bottom of the floor joists and the earth under any building (except space occupied by a basement) shall have ventilation openings through foundation walls or exterior walls.
Encapsulated Crawl Spaces: R408.3 Unvented crawl space. Ventilation openings in under-floor spaces specified in Sections R408.1 and R408.2 shall not be required where there a continuously operated mechanical exhaust ventilation fan that exhausts air from the crawl space at a rate of 1 cubic foot per minute for each 50 square feet of the crawl space floor area.
Why use our Foundation Vent Fan?
Our foundation vent fan is reasonably priced, easy to install and exhaust 340 CFM of air from the crawl space.
What is CFM?
Air movement is measured in CFM (Cubic Feet Per Minute). To calculate the volume of air in the crawl space you multiply the height x width x length of the crawl space. For example, if your crawl space is 40’ long, 20’ wide and 3’ high the volume of air in the crawl space is 2,400 cubic feet. If you want to replace the air in the crawl space every 4 minutes you need a 600 (2,400/4) CFM fan.
What is the benefit of using a humidistat?
A humidistat regulates when the fan will turn on or off based on the
humidity in the crawl space. You usually want to set a humidistat at 50%.
So, if the humidity rises above 50% the exhaust system will turn on and
move air out of the crawl space. This will also keep the fan from running
all the time extending its life.