Mildew is a mold that grows under warm (temperatures between 77 – 86 degrees F.), wet, and humid conditions (relative humidity between 62% - 93%).
Window condensation is one visible manifestation of excess humidity, but ideal conditions also are found lurking out of sight within wall cavities, in crawl spaces and attics.
Under saturated conditions wood will rot, giving rise to frequent and expensive repairs, and mold spores serve as triggers for allergies and contribute to an unhealthy home environment.
You don’t have to open doors and windows to bring moisture into our home. Outside humidity, moisture generated in the home, vapor pressure (the drive that causes moisture to migrate to dryer areas), all contribute to the problem. Exhaust only ventilation (bath fans, range hoods, dryers) as well as the stack effect from a chimney will accelerate the infiltration of outside humidity through poorly installed (or non-existent) air barrier. Cumulatively this moisture can add hundreds of pounds of water per day to a home.
Here is where an ounce of prevention is worth 100s of dollars of expensive water removal using dehumidification/air conditioning, building repairs and potentially medical expenses and even debilitating illnesses for family members.
Remediation and Prevention
Building/remodeling right and ventilating right, along with occupant awareness to reduce moisture generation will have a major impact on the prevention of moisture issues that lead to mold growth.
The Building Envelope
Minimize paths of infiltration by sealing your home and adding insulation, install a vapor-permeable air barrier, prevent water from entering basements and crawl spaces with proper sealing, drainage, and landscaping. Don’t forget to clean the gutters.
A Ventilation Strategy
Install an Energy Recovery Balanced Ventilation System. The UltimateAir® RecoupAerator,® model 200 DX will exhaust excess humidity (along with odors, stale air and pollutants) in the winter and leave a percentage of the humidity outside in the summer while bringing in an equal amount fresh filtered air. This balanced ventilation approach will help prevent unwanted infiltration by keeping the home at balanced or slightly positive pressure most of the time. It is also the most cost effective way to provide the ventilation necessary for a safe, comfortable and durable home.
A well-ventilated, balanced- pressure home with a 35 – 45% RH is one of the best investments you can make to prevent mold, reduce allergy triggers (both pollens and mold spores) and insure the health of your family.
UltimateAir's Jason Morosko writes about moisture, mold, indoor quality and other topics. Stay tuned!