Here’s How Soffit Works to Keep Your Home Dry

D.P. Taylor
Written by D.P. Taylor
Updated December 28, 2021
Attic red brick house with soffit
Photo: bildlove/Adobe Stock


  • A soffit vent goes under the eaves of the roof to ventilate the attic.

  • They reduce energy consumption and increase roof lifespan.

  • They’re vulnerable to animals and may damage roofs.

  • The four types are: individual, continuous, perforated, and circular.

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At any given moment, unseen forces like moisture, mold and animals are hard at work trying to destroy your home from within. But no need to worry—that’s where soffit vents come in. These vents are particularly important because they protect the interior of your roof and attic, which are often out of sight and therefore out of mind. Here’s how soffits work to keep your home free from moisture damage.

What Is a Soffit Vent?

A soffit vent is a device that is installed underneath the eaves of a roof that allows for fresh air to get into the roof. These vents are visible on the underside of the eaves. They create a continuous flow of fresh air throughout the roof and attic, which protects against moisture.

What Is the Difference Between Eaves and Soffits?

Eaves are the part of the roof that extend past the edge and hangs over the ground. Soffits are vents installed within these eaves to allow airflow.

What Is the Difference Between Fascia and Soffits?

The fascia is the board that runs along the side of the overhang and is typically there for aesthetic purposes. It's essentially a trim, although it does provide some support to the shingles.

What Are the Benefits of Soffit Vents?

Soffit vents preserve energy, lengthen a roof’s lifespan and prevent moisture problems like mold and mildew.

Reduces Energy Consumption

A good, consistent flow of fresh air throughout the roof and attic will better prevent heat from escaping the home. This helps the A/C and heating units work less, which means you reduce energy consumption and therefore lower your energy bill.

Increases Roof Lifespan

Poor attic ventilation is one of the biggest reasons a homeowner might need to replace their roof early. Proper ventilation will increase the lifespan of your roof by ensuring your attic is getting the fresh air it needs.

Prevents Black Mold

While it may seem strange that allowing cold air in the winter into your attic can improve insulation, the fact is that this fresh air helps ventilate moisture created in the interior home from activities like heating and showering and all the other things people do. This further prevents toxic black mold from forming by starving it of moisture. This process also helps remove moisture in the summer as well, moving hot air out of the attic.

What Are the Downsides of Soffit Vents?

Soffit vents don’t hold up well against animals and the elements.

Vulnerable to Animals

Raccoons, bats, and other types of critters can tear off the soffit screens to get into your attic and set up shop. As a result, you should inspect them regularly for damage. The cost to repair soffit ranges from $600 to $6,000.

Risk of Damage to the Roof

Because moist air can collect under soffits, they can risk damaging your roof as well as any siding in the general vicinity over time. Watch for signs of damage and contact a professional if you are concerned about moist air build-up.

May Suck Moisture Into Attic

Soffit vents are intake vents, which means if they are positioned near an exhaust vent, it may suck moisture into your attic and cause damage.

False Vents

Some older homes have soffit coverings underneath the eaves, but they are installed directly over wood and there's no actual vent there. You can determine if this is the case by removing the panel to see if there's an option. If not, choose a soffit repair contractor to convert them into vents.

What Are the Different Types of Soffit Vents?

close up of soffit on house
Photo: tamas/ Adobe Stock

There are four main types of soffit vents: individual, continuous, perforated, and circular.


This is probably the most common type of soffit vent. They fit between joists under your eaves. They're called individual vents because it is just one vent all by itself, perhaps with a gap separating it from other individual vents.


A continuous event runs along the entire underside of the eaves to maximize the amount of air the vents pull in.


These vents are simply perforated vinyl siding that resemble regular vinyl siding, except with tiny holes. They're particularly good for keeping animals out.


These vents are less common because they don't work as well as other types of soffit vents. Because of their circular shape they may look like lights installed underneath the eaves, but they are vents.

Can You Have Too Much Soffit Ventilation?

It is possible to have too much soffit venting. Soffit vents are intake vents, and therefore they need to be balanced out by exhaust vents. If your home is seriously out of balance between soffit and exhaust vents, your soffit vents could be allowing moisture build-up.

How Much Does an Individual Soffit Vent Cost?

worker installing soffit on home
Photo: kuchina/Adobe Stock

It costs between $315 and $465 on average to install soffit vents. Generally, that comes out to between $3.30 and $4.50 per linear foot. A continuous soffit vent would cost $8 to $10 per square foot. Contact a roofing professional near you for an estimate.

How Do You Know If Your Soffit Vents Are Working?

The best way to figure that out if your soffit vents are working is to climb into your attic and inspect them from the inside. These vents can get blocked by insulation, which can result in severe mold build-up. Check each vent to ensure that there is nothing blocking the vents.

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