Ventilation: Static vs. Mechanical

Ventilation: Static vs. Mechanical
April 26, 2018 Kristina Ray
In Roof Ventilation

Ventilation Types: Static vs. Mechanical

Ventilation helps circulate air in and out of your attic. Heat naturally rises and flows up through your attic like a teepee. Ventilation creates suction that pulls air into the eave soffits and out through the exhaust vents on top of the roof.

Ventilation is necessary because the roof needs to breathe. Without proper vents, the roof would blister and cause nails to back out puncturing through the shingle. Ultimately causing rotted decking, leaks and damage to the inside of your home.

There are two different classifications of exhaust vents:  static and mechanical.

First, Static vents have no moving parts. Low profile vent, hip vent and ridge vent are all static vents.

  • Low profile vents are standard ventilation. Code requires one per every 150 ft3 of attic space.
  • Hip vent is similar to ridge vent but it runs down the hips of the roof. It is rarely used and relatively new.
  • Ridge vent is becoming more and more common because of how well it works. Ridge vent runs along the ridge of the roof and displaces a large amount of air. When using ridge vent it’s important to shingle over the old exhaust vents because ridge vent should be used alone.

Second, mechanical vents have moving parts. Solar vents, power vents and wind turbines are all considered mechanical vents. Code requires one mechanical vent for every 300 ft3 of attic space.

  • Solar vents are fans with a motor powered by the sun. They generate their own electricity and are very powerful. Solar vents should be place at the top of the roof away from any static vents. Most solar vents are constantly running.
  • Power vents run off your electricity and have a thermostat so they turn off and on. The thermostat hangs down from the vent into the attic and turns the vent on once a certain temperature is reached.
  • Wind turbines are non-electric alternatives. They use the wind and a rotary fan to vent the hot air from the attic.

Mechanical vents and static vents should not be placed beside each other. The mechanical vent will simply pull air through the static vent and not through the soffits. It’s important to know what type of vent will work with your attic. To see what’s right for your home, CONTACT US at Ray & Sons Construction.