Attic Ventilator

Take a load off your air conditioner

Have you ever been in your attic in the middle of the summer? It’s HOT! That’s why you need an attic ventilator. Assisting your air conditioner in cooling your home and in lowering your utility bills, an attic ventilator exhausts the hot air from your attic and brings in cooler air from the outside. This circulation of air greatly reduces the heat load on your home allowing your air conditioner to work more efficiently and to cool your home faster. Adding an attic ventilator to your home will save you money and make you more comfortable.


  • Proper attic ventilation is an important part of a healthy home-both for the structure and its occupants. This document explains how attic ventilation protects a home from moisture and how to install vents that will keep your home in good condition.
  • There are a wide variety of sources of moisture in a home, from the building materials themselves to normal everyday activities. Cooking, bathing and washing clothes all release gallons of water vapor into the air, for example.
  • That vapor isn't a problem inside the average home because the temperature inside the home is warmer than outside for much of the year. Warm air holds more moisture-in the form of water vapor-than cool air.
  • The problem is that vapor gradually works its way out of the living area and into the structure. As warm, moist air cools, the vapor begins to condense into water droplets. If that happens inside an unfinished attic, for example, it can get insulation and framing materials wet. That not only reduces the value of your insulation but can cause mold, mildew and rot.
  • During the summer, when the outside temperature is typically much higher than the inside temperature, attic ventilation serves a different purpose. An unfinished attic builds up a tremendous amount of heat, and if that heated air has no place to escape, it can make the inside of the house much warmer or cause an air conditioning system to work much harder to
    cool the house.

  • A good attic ventilation system is designed for summer needs. It includes two types of vents: intake vents are placed along the soffit to allow fresh air into the attic, and exhaust vents are installed in the upper third of the roof to allow attic air to escape. The object is to create a continuous "wash" of air along the underside of the roof sheathing. The rule of thumb in the summer is that you should provide enough ventilation to completely change the air in your attic every six minutes.

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