ventilation

Tackling Condensation

Merely being in a building (either residential and commercial)and performing daily activities such as breathing, bathing, operating washing machines, dishwashers, etc. produces moisture in the indoor environment. This moisture saturates the air producing the harmful effects of condensation.

Condensation is caused when moist, warm air hits a cool surface such as an outside wall or the glass in a window. The air is moist because its water content hasn't been removed. A family of five can generate up to 3 1/2 gallons of moisture per day. Proper ventilation is the best way to remove excess moisture in the air.

Controlling ventilation can be accomplished in one of two ways or better yet, a combination of both: that is mechanically or naturally. Mechanical ventilation includes the use of furnaces, heat pumps, air conditioners, dehumidifiers and exhaust fans. Natural ventilation includes opening windows, doors, integrated window ("trickle") ventilators and through-the-wall devices. Of course, a proper combination of natural (sometimes referred to as background, static or passive) and mechanical ventilation is the goal.

New construction techniques, i.e. "build tight", typically reduces natural ventilation. Opening windows and doors is being discouraged in climates where heating is required by most utility companies because of anticipated increased energy costs. In addition, occupants are sensitive to the discomfort of drafts created especially by open windows. In combination with exhaust fans not only in high moisture producing areas such as kitchen and bathrooms but all through the home or building, "trickle" ventilators provide a controlled amount of fresh air in small but adequate quantities. The small but adequate amount of fresh air circulates around the window area keeping condensation at a minimum. The small controlled flow of air through a trickle ventilator is like the defroster in an automobile - a little slower but equally as effective.

To summarize:

  • Builders are constructing tighter houses and buildings to reduce energy cost sacrificing needed controllable natural ventilation.
  • Tight construction creates excess moisture inside a building or home causing undesirable condensation to form on glass in windows as well as on other surfaces.
  • A family of five can generate as much as 3½ gallons of moisture per day.
  • Opening windows for natural ventilation causes undesirable drafts and increases the need and cost of energy.
  • Trickle Ventilators in combination with exhaust fans is a proven method of natural ventilation to remove excess moisture and reduce condensation.