Bathroom Vent: Soffit vs. Roof (Detailed Comparison)

Installing a bathroom fan comes with one huge dilemma: should you vent it through the roof or through the soffit? The soffit sounds more approachable, especially if you want to install the vent yourself. But is it really the best choice?

When deciding between a bathroom vent through the soffit or roof, keep in mind that soffit vents can have a lot of problems. Installing a roof vent requires more skills, but it’s the appropriate choice for taking moisture and eventual sewer gas leaks out of your home.

4 Bathroom Exhaust Fan Venting Options

There are several venting options when installing bathroom fans; however, some are more effective than others. Let’s have a look at them.

Roof Venting

One of the most popular venting options, roof venting, takes the moisture and fumes outside of your house through the roof.

This venting system is relatively challenging to install because it could leak if installed incorrectly. However, this system is the best option if you want to prevent humidity problems inside your bathroom and home (moisture and heat rise naturally, so this venting type aids them to escape your house). 

A disadvantage is that snow, fallen leaves, and bird nests could clog it.

Ceiling to Wall Venting

This venting option uses the same principle as the roof one, but a horizontal duct connects the fan with a vent hole located in the wall, near the ceiling.

This installation is preferred when you can’t use a roof vent for some reason – for instance, if you live on a lower floor in an apartment building. 

The main advantage of the ceiling-to-wall venting is that it doesn’t leak as fast as a roof vent, but rain could still get inside and leak along the wall if the vent isn’t installed properly. 

Wall Venting

One of the simplest setups, a wall fan and vent, is another type of installation used in apartments. Similar to the ceiling-to-wall vents, these vents are less likely to leak compared to the roof type. Depending on the vent type, you’ll have to install the fan on an exterior wall or on any interior wall if you can route it through the ceiling or other walls.

Soffit Venting

Roof soffits are the underside portion of the roof that hangs over the walls. Soffits generally have a type of passive ventilation similar to ridge or gable vents. 

Soffits have an important role in attic ventilation, but they aren’t exactly the first choice when it comes to exhaust fan venting. The main disadvantage is the fact that the cross-ventilation could conduct moisture and heat into your attic rather than outside.

Directing bathroom air into the soffit also requires more ductwork. Sure, there is no risk that the vent will leak, but there is a high probability it won’t work properly. If you really want to run the vent through the soffit, there is a way, though. More about this below.

Venting A Bathroom Fan Through The Wall

Venting through a wall – be it an interior wall, exterior wall, or directly through the roof – is the best bathroom venting solution. Either of these options will get rid of the moisture, heat, and fumes in your bathroom, leading them out of the house.

Pros of Venting through a Wall

Proper ventilation through a wall, ceiling, or roof will limit condensation in your bathroom and prevent mold and mildew growth. But there are other essential benefits of this venting type. 

  • Enhanced comfort: The increased effectiveness of wall or roof venting increases living comfort by reducing humidity levels. You can check the moisture level in your house with a digital hygrometer or smart home system to see how the bathroom fan can make a difference.
  • Better health: Lower humidity levels can help keep bacteria and mold at bay. These microorganisms can cause allergies or trigger asthma symptoms. Moreover, both mold and bacteria can cause various respiratory infections.
  • A more durable bathroom: Fewer condensation problems mean fewer problems in the bathroom. You won’t have to repaint as often, nor will you have to change the fittings and accessories too often. If you have hardwood floors, a proper exhaust fan and venting system can also protect them.
  • Less noise: Properly routed vents are definitely quieter compared to soffit venting systems. If you’re not fond of loud fan noises, this solution could be right for you.

Cons of Venting through a Wall

Perhaps the main disadvantage of roof and wall vents is that they can leak if installed improperly. Birds often build their nests in the exhaust fan vents, and wind can also send lots of debris straight in. Rain could also make its way through the vents straight into your bathroom.

Venting A Bathroom Fan Through Soffit

Venting through a soffit could seem like a good idea if you don’t want to make holes in your roof or walls. However, soffit venting is problematic and banned in some states. You should check your local regulations before even thinking about a soffit vent.

Pros of Venting through Soffit

Like wall or roof vents, soffit vents have advantages of their own. In addition to the installation ease, they are less likely to get clogged.

  • Easy installation: Soffit vents are easier to install compared to wall or roof vents. This project is more approachable for most DIYers, but remember that soffit vents aren’t legal in all states. Check the local laws before venting the bathroom fan through the soffit, or you could risk a fine.
  • No leaking problems: Soffit vents don’t open on the outside of your house, but in an enclosed space between the ceiling and the attic. Thus, you don’t have to worry about any leaking problems.
  • Fewer blockages: Just like rain can’t make its way to the vent, birds and debris can’t make their way either. Soffit vents are less likely to clog and easier to clean.

Cons of Venting through Soffit

The main disadvantage of soffit vents is that they might not work. The soffit has static ventilation that helps recirculate the air in the attic. Thus, instead of sending the moisture, hot bathroom air, and fumes out of your home, it could send them straight into the attic. 

Apart from mold and mildew, the extra humidity can also damage your attic’s wooden structure, and the moisture and fumes could eventually work their way back into the bathroom or other areas of your home.

Is It Better To Vent Bathroom Fan Through Roof Or Soffit?

You should always vent your bathroom fan through the roof or, if the roof is inaccessible, through a wall. Venting through the soffit is never a good idea.

FAQs: Answers You Should Know

Now that we established how you should vent your bathroom let’s see the answers to some other common questions.

What is the best roof vent for a bathroom fan?

There are many bathroom roof vents you can buy, and which is the best depends on your circumstances. The main things to look for are proper covering and adequate sealing. Once installed, you should have to add additional sealant nor install additional coverings.

What is the code for venting a bathroom fan?

Toilet rooms and bathrooms, when not provided with natural ventilation, should be ventilated by an exhaust fan with a minimum of 50 CFM. The exhaust air should not be recirculated within the residence and must be exhausted directly to the outdoors through an appropriate roof or wall vent. 

Do I need a separate vent for each bathroom fan?

Yes, each bathroom fan needs its own vent.


Soffit venting could sound tempting, but you should steer clear of it. Not only can it exhaust bathroom air back into your house, but it can lead to humidity problems in your attic as well. Roof venting might be harder to install by yourself, but it keeps your environment healthier and reduces bathroom maintenance costs.

So, what do you say? Which kind of vent system do you prefer? Tell us in a comment.

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