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Can You Vent a Bathroom Fan Into the Attic?

Can you vent a bathroom fan into an attic is a question I often hear asked. For some people that are unaware, it may seem like a good idea.

Unfortunately, it is usually not a good idea as venting a bathroom fan into an attic goes against most regions’ building codes and regulations.

If you already vented your bathroom fan into your attic and are looking for a way to resolve this issue, or if you have a unique situation and need to vent into your attic, there are ways to solve this issue.

bathroom exhaust fan

Venting a Bathroom Fan Directly Into the Attic is a Bad Idea

Building Codes and Regulations

In most areas of the world, venting a bathroom fan directly into the attic is against code. If a building inspector were to find out that you vented your bathroom fan into the attic, you would receive a notice of violation.

This notice usually gives you a specific amount of time to re-do the work and fix the issues the inspector found. If you do not resolve the problems in time, you will receive fines, and other actions may be taken against you.


Bathroom air is unlike the rest of the air in your home. The air in your bathroom often contains moisture. When this moisture-rich air is vented into your attic, it can cause mold and mildew.

This mold, if not dealt with in time, can cause structural damage to your attic, your insulation, and your roof. Structural damage caused by mold can be very expensive to repair. Besides structural damage, mold also carries with it health concerns.

Bad Environment For Ventilation

Your attic is one of the worst areas in your home when it comes to ventilation. Attics are closed off and are often at a different temperature than the rest of your home.

Though you may only be in your attic on rare occasions when you do enter your attic, you will have a more hot, humid, and possibly foul-smelling environment to deal with by venting your bathroom fan into your attic.

Also, since your bathroom air is trapped in your attic, it is possible for that air to blow back into your bathroom or other areas of your home.

How Can You Vent a Bathroom Fan Through Your Attic

Vent Through The Soffit

Soffits are a popular choice to vent the air from your bathroom through your attic and take it outside. The soffit is the underside of your roof and is a great place for a vent.

Venting through a soffit has benefits, including an easier installation. Soffits are great for areas with heavy snow as they are less likely to be blocked by snow than roof vents. Soffits are also great for when you have no access or have a difficult time accessing your roof. As long as you have access to your attic, a soffit vent is a relatively easy install.

Installation Cost

The cost of the fan and other materials, along with doing the installation on your own will cost you between 300 to 500 dollars.

Vent Through The Wall

Similar to a soffit, you can install an air vent right through the wall. This is the least popular option as it requires additional installation work.

You can create an air vent that leads back to your bathroom through the wall of your attic or garage. Making an air vent through a wall can affect your insulation and frame. This can lead to additional work to keep your home properly ventilated.

Occasionally there is more ductwork involved in installing through a wall. This additional ductwork can affect your ventilation.

Installation Cost

The price of venting your exhaust fan through an exterior wall can range from 400 to 700 dollars.

Vent Through The Roof Gable

Venting a bathroom through your roof gable is a popular choice and is equivalent to venting straight up through your ceiling. This method of ventilation is relatively easy to install and gives your bathroom exceptional ventilation capabilities.

One issue with venting through your roof is if you are in a region with heavy snowfall, the snow can clog or block off your roof vent. Another problem that some have with venting through the roof is you need to actually climb on the roof during the installation process.

Installation Cost

The price of installation for venting a bathroom fan through the roof gable is comparable to venting through a soffit which is around 300 to 500 dollars.

Things to Consider When Venting a Bathroom Fan Through the Attic

Climate Considerations

One important thing to always keep in mind when installing ventilation is the type of climate you live in.

If you live in a sweltering area, the humidity will be a significant factor in your ventilation process. The higher humidity will sometimes require a more substantial fan with more direct ductwork leading outside.

Cold temperatures can make the air very dry, which can cause coughing or shortness of breath if not ventilated properly.

Bathroom Location

The location of your bathroom can drastically affect your options when installing your ventilation. For example, it would make little sense to vent a bathroom in your basement through your roof as the ventilation would have to run right through the main floor.

The most efficient ventilation is achieved when your ductwork can travel the shortest and straightest path possible. The location of your bathroom will dictate where it will be best ventilated.

Choosing the Right Fan

Bathroom fans come in different varieties and styles and can cost you anywhere from 50 to 300 dollars. But price should not be your only consideration.

Depending on where you are venting your bathroom air, different fans will work better. There are three general categories of bathroom vent fans which are ceiling-mounted, wall-mounted, and inline or remote.

Backdraft Dampers

An additional product to consider is backdraft dampers. These dampers are installed in your ductwork and allow air only to flow outward, preventing air from flowing back into your home.

In certain situations, backdraft dampers can be especially useful. If you are running long ductwork, have multiple vents connecting, or if you live in a very windy area, backdraft dampers can be pretty helpful.

Adam McCoy

Adam is an HVAC expert and the owner of Mackydo's HVAC Services with decades of experience in fixing and installing air conditioning units, furnaces, and every type of cooling and heating equipment you can think of.

Adam believes that your home is your sanctuary. He loves sharing advice based on his lifelong experience and treats every HVAC problem as if it was his own.

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