Power Attic Ventilators vs. Passive Ventilation
- Powered fans are sometimes installed in attics to assist in creating good air circulation. These fans require electricity, and therefore are more expensive to use than passive ventilators, but are ideal for hot climates where the outside air is not much cooler than the warm air inside the attic.
- Passive ventilators also pull hot air out of the attic and replace it with cooler air from the outside. But as the name implies, they do so without using an electrically powered fan. Passive ventilators are typically installed when the home is built; types of passive ventilators include soffit vents, rafter vents and any other type of ventilation that does not use electricity to move air. The major disadvantage of passive ventilators is that they can only pull in cool air when there is cool air outside; in dry, desert-like climates and during hot summer months, passive ventilators may not be as effective.
- Active ventilators can be energy-efficient, as long as certain conditions are met. If there is not a tight seal between your attic and the rest of your home and if your attic has blocked soffit vents, active ventilators actually pull air-conditioned air from the home below into the attic. This helps to cool the attic, but the air conditioner has to work harder to cool the rest of the home due to the loss of cooling efficiency.
- Regardless of which type of ventilator you choose, its effectiveness will be compromised if other maintenance is neglected in the attic. Keep tight seals in the attic and make sure to install R-30 or better insulation. Regularly monitor the insulation, and check it for wetness; wet insulation from roof leaks is ineffective, making it all the more difficult for ventilators to control temperatures inside your attic.
