Why Your Attic Needs to Breathe

Attic ventilation is a system that lets air flow in and out of your attic. It usually has two parts:

• Intake vents: These are usually placed near the bottom edges of the roof in the form of soffit vents. They let fresh air in that pushes the warm, stale air up to the top of the attic.
• Exhaust vents: These are located near the top of the roof and can take the form of ridge vents, attic fans, turbine vents, or box vents. They let hot, moist air out.

The Chimney Analogy

If you’ve ever watched a fireplace in a home, you’ve noticed how the smoke rises and escapes out the top, while fresh air and oxygen keep the flame going at the bottom. If no air comes in, the fire struggles, and the smoke just sits there. Your attic works the same way!

Without a way to intake air into the home, there’s no way to actively exhaust stale air. This causes the air in your home to become stagnant, and humidity to build up.

Why It’s Important

1. Keeps Your Attic Cooler and Drier in Summer

Hot air rises, and without ventilation to let that hot air escape, your attic can reach around 120 degrees Fahrenheit or higher. This makes it harder for your home to maintain a consistent temperature, overworking your HVAC system, and leading to higher energy bills.

2. Prevents Damage from Ice Dams

When the hot air in your home rises and becomes trapped at the peak of your roof in winter, it may melt the snow on top of the home, causing it to melt down and refreeze along the eaves, where it’s colder. This forms ice dams, which are thick ridges of ice that block melting snow from reaching your gutters. Proper ventilation helps keep the attic at a consistent temperature that prevents this problem.

3. Controls Moisture Problems

Everyday activities within the home, like showering, cooking, or even breathing, add moisture to the air. Some of that moist air drifts upward into your attic, where it may become trapped, leading to mold, mildew, and rotting wood. Ventilation allows moisture to circulate and escape before it causes trouble.

The Science Behind It

Ventilation works because of a singular natural force:

Convection: Air always moves from high pressure to low pressure. When cooler, denser air comes in through the intake vents, it pushes the warmer air out through the exhaust vents.

Together, these forces keep air circulating like a loop, with fresh air coming in and stale air going out.