Ventilators – Simple Science To Address Moisture Intrusion

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Ventilators – simple science to address moisture intrusion-1

If you’ve ever dealt with a damp/wet basement or crawl space in a new home it can be difficult to address. In older homes, it’s almost impossible to permanently correct. But you can manage it with an understanding of some simple Building Science.

Moisture Degrades Building Materials & IAQ

High humidity in your home supports a cave-like environment that attracts insects and biological organisms, encourages biodeterioration and degrades Indoor Air Quality. Moist areas are commonly found in basements and crawl spaces, but can also lurk inside wall cavities, closets, and places with poor ventilation (like attics).

Moisture Migration in Your Home


Capillary Action is a natural biological process often called “Rising Damp” in a building. This is how moisture migrates into a home and has been a concern in dwellings since Roman times. Understanding this process is key to its successful management.

Ventilators Help the Natural Process of Air Flow

Ventilators help

Air moves through a home in several different ways; naturally (all the time) via “Stack Effect” and weather effects (wind & air pressure); and intermittently via the homes’ mechanical heating and cooling system (HVAC). Simple ventilators help a home “Breathe” better even when the HVAC system isn’t running which helps manage moisture in your home.

Some Things to Be Aware Of

Some things-maintenance-

First, no system is perfect. But being observant and using your best good judgment may help you not getting caught off guard. When using mechanical ventilators of any kind, watch out for:

  1. Air Flow: Opening doors/windows impact airflow throughout the home and may have unintended effects. For example, opening a basement door on a hot humid day in summer will cause exterior air to rush into the basement and cause a dew point to be reached on AC ductwork triggering a condensate issue. Opening a window in fall might draw smoke-laden air in from a neighbor’s campfire or fireplace.
  2. Fan Sounds: Some seasons are wet (February – April), some are dry (October – January), there’s hot and humid (July & August) and some are in between. The speed of the ventilator fan fluctuates based on humidity it senses and regulates to compensate. In wetter humid months your ventilator will be running at max while in dryer months you may hear nothing at all as it tends to slow down.
  3. Maintenance: Today’s ventilators do require maintenance in the form of wiping the grill cover once in a while. Check the exhaust cover where a slight grate movement indicates your system is running. Or have GreenWorks do it annually for you just to be safe.

Looking for More Resources

EPA & Building / Home Ventilation

DOE / NDSU / Foundation Insulation Effectiveness: Basement Building Science


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Avatar for Victor Coppola

Victor Coppola

Victor Coppola is a Building Biologist with decades of diverse environmental experience spanning natural resource management and contaminated sites to Indoor Air Quality (IAQ) and building hygiene matters. He focuses on the three most prevalent issues degrading today's built environment: Moisture Odor & Mold (M.O.M.). Mr. Coppola and his Team are sought out by individuals and professionals concerned about IAQ to those actually suffering from Biotoxin Illness. His hybrid blend of environmental interests and services enable him to give a unique perspective into today's changing environment. Think your home is killing you, better call Victor and his Team at GreenWorks.
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