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Ventilation
An attic ventilation system consists of intake vents and exhaust vents. Together, these products can be used to create a balanced attic ventilation system that helps to reduce attic temperature and excess moisture.
Intake vents, located at or near the bottom of your roof, are a very important part of your attic ventilation system. These vents allow fresh air from outside into the attic. If there’s no air coming in, then no air can flow out, reducing the effectiveness of the attic ventilation system and potentially causing roof system degradation.
This air current continually flows through the attic and then back outside through exhaust vents positioned at or near the top of your roof. The vents help protect the roof system from the inside out. It’s important that the amount of exhaust ventilation at or near the ridge does not exceed the intake air ventilation at or near the soffit.
Exhaust ventilation is most efficient when it’s installed at or near the highest point of your roof where hot, humid air can easily escape. Exhaust vents are divided into three common categories: static, powered, and mechanical.
Try to maintain a 50/50 airflow balance between intake and exhaust
Benefits of proper ventilation
Reduce Humidity Buildup
Helps Prevent Ice dams
Extends Roof Life
Helps with AC Costs
Which Types of Roof Vents are Best for my Home?
Every home is different. The best vents for your roof will depend on your home’s architectural style, the design of your roof, and your local climate. It’s important not to mix different types of exhaust vents in the same attic space, which can prevent proper airflow through the space.
- Ridge Vents
- Powered Exhaust Vents
- Mechanical Exhaust Vents
- Roof louver (Box Vents)
Low Profile Vents
They are the most common vent you will find on a roof. They are also called “mushroom vents” due to their appearance.
They are not the most efficient system available. But when your roof cannot utilize ridge venting, they become an excellent option.
Airflow rendering
This is merely a representation of how air can flow thru the low profile vent. Because they are installed on one side of the roof (typically on the back to hide them). There will always be a favoring of air flow and inefficiency on the opposing side.
Ridge Vents
Hot Air RISES! So the best place to have a vent is at the peak. Low profile vents are placed lower from the ridge line so you will always have a pocket of hot air at the peak that has no where to exit.
Equal venting
Ridge vents allow for equal air flow from both sides of the roof to prevent as much dead space as possible.
Airflow will extend your roofs life, your air conditioners life, and prevent some life threatening molds from growing.
Passive systems require no maintenance.
This photos is a great depiction of air flow and how ridge vents are the only solution that prevents air from being trapped in the ridge.
The other options exhaust short of the ridge.
(Image credit to the Family Handyman)
For the best performance, each attic space should only have one type of exhaust method!
This issue was spotted in Naperville while we worked nearby.
You can see multiple issues such as the extra vents placed in the middle of the roof and then the addition of a power vent next to them.
The power vent will suck in air into the attic from outside, then draw it out, then cycle it back thru again so the lower air never gets extracted and the heat and the humidity stay trapped.
