How to vent a bathroom without outside access

Venting a bathroom is a critical task that a homeowner should take time to complete. Venting your bathroom can be done, but some methods are more efficient than others. Keeping your bathroom ventilated may be one of the most challenging tasks of your day. There are several ways to vent a bathroom, but most of them require outside access. 

How to vent a bathroom without outside access by using a fan that vents? You might vent the bathroom by using a fan that vents the air through the attic or by installing an exhaust fan on the roof. Each option will have to be costly and time-consuming, as there is no quick fix.

If you’re living in a small apartment or a home with no outside wall for access to your bathroom, you can still enjoy good ventilation. You just need to get creative.

Venting a bathroom seems simple enough: just open a window or install a fan, right? Well, it’s not quite that easy. There are some strict building codes that regulate how you vent your bathroom—and they’re specific. You can’t just use any window or fan. To comply with local ventilation laws, you need to make sure your bathroom has continuous airflow and the right ducts that vent out of the house.

Ventilation laws are different in every state and city, so talk with your local building inspector before you plan. But here’s one way to vent a bathroom without outside access—just keep in mind that it might not meet your local building codes.

If you have a bathroom with no outside access and are looking for an easy way to vent it, don’t worry! There are a few different ways to do it.

Do you have a ventilation problem?

Have you ever been in your bathroom and felt that the moist air was stale or stuffy? Did you get a whiff of something unpleasant? If so, it’s likely that you have a ventilation problem.

It may seem like a simple annoyance, but mold, mildew, and other moisture-related issues can lead to serious health problems in the long term unless properly addressed. Luckily, most bathroom ventilation issues are easy to fix!

Don’t worry if your bathroom doesn’t have an outside window, or a fan installed. You’re not alone! This is an extremely common problem for people who live in apartments and older homes. In both cases, there may be no easy way to install new equipment without breaking through walls and ceilings.

The most important thing to know is that bathroom vents are essential. If they’re not installed properly, they could cause mold growth, and if they’re not installed at all, you could face serious health risks. So don’t ignore this problem—you might have some work to do, but you can solve it.

Why is Venting in a bathroom necessary?

There are many reasons a bathroom needs to vent properly. One of the most common reasons is that a toilet backs up or there is a gas leak in the room. When this happens, the air quality inside the room gets worse and worse because nothing can get in. This can even lead to deadly fumes that leave you feeling uncomfortable and unable to breathe.

If you have no way for air to flow into the room, it will be difficult for air to get out too. There will be an increased chance that odors from your bathroom will linger and spread throughout your home. Not only that, but it’s possible for moisture levels to increase as well if there isn’t anything for them to escape with.

The purpose of a bathroom vent is to remove odors, moisture, and excess heat from the bathroom. Moisture can cause structural damage and ruin drywall, causing mold or mildew to form. Excess heat can cause higher energy costs when running a fan or air conditioner.

Bathroom venting helps to prevent the growth of mold and mildew by ensuring that excess moisture is removed from the air in a timely manner. While venting all bathrooms with windows to the outdoors is ideal, sometimes a bathroom simply does not have access to an outside wall or window. Fortunately, it is possible to ventilate a bathroom without windows by using a compact fan.

Alternatives to Venting a Bathroom with No Outside Access

If you thought that venting into an enclosed bathroom without outside access was impossible, you’re wrong. There are many solutions to this problem, such as a roof vent, roof monitor, and bathroom fan. A roof monitor is an exhaust fan mounted on the roof of your house that can get rid of any potential odors in your bathroom through a stack or duct. A bath vent fan is also an option for ventilation because it can remove unwanted moisture from a bathroom without relying on the benefits of fresh air from outside sources.

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Common Signs That Your Bathroom Requires More Ventilation

If you’re worried that your bathroom might not have enough ventilation, stay alert to these common signs:

Bad Smells:

Odors are a sign that there’s not enough ventilation in your bathroom. Opening your bathroom door after a shower should give you an easy way to get the smell out, but if your bathroom still has that “just showered” smell hours later, then you have an air quality problem.

Mold Growth:

Mold is an unsightly and potentially dangerous problem — not just in bathrooms. It can cause respiratory problems or allergies, and if left alone, it can lead to serious structural damage.


Like mold, mildew is a sign of too much moisture and not enough ventilation in the bathroom.

Water Damage:

It can cause water damage from several things—from leaky pipes to cracked tiles and more—but one of the most common causes is excess moisture from inadequate ventilation in the bathroom.

Stained Bathroom Ceiling 

If there are stains on your walls or ceiling, you don’t have enough ventilation. It shows that the moist bathroom air has resulted in an excess of moisture in the home. Poor roof design and installation, as well as bathroom venting, frequently caused stains, resulting in a large amount of moisture under the roof. You should also inspect whether it installed the roof vent at a high level.

Windows that don’t open easily. If you have windows that don’t open easily, it may be a sign that they’re stuck closed because of excess moisture in the air because of a lack of bathrooms ventilation.

Types of ventilation systems for a bathroom

There are many factors that affect the ability to vent a bathroom properly. The key factors are the overall layout of the home, as well as where the bathroom is located within the home. Sometimes you will have to make modifications to existing ventilation or install a new system altogether.

Venting typically refers to releasing pressure from a confined area. Venting bathrooms usually occur when there is a clog in the toilet or drain pipe that causes the water to rise and build up in the bowl. There are many types of vent systems you can use, depending on what type of access you have. 

When a bathroom is on an inside wall, there will be no access to an outside wall for a bathroom exhaust fan. Here, you will need to install another type of ventilation system.

Proper ventilation systems for bathrooms without outside access include:

1. Gravity-fed exhaust fans: 

Gravity-fed exhaust fans pull air from a room through a duct into the main vent that is vented outside through the side of the house or through the roof. We often use these in mobile homes and condominiums where there is no access to an exterior wall from inside a bathroom. Gravity-fed exhaust fans are relatively inexpensive and require little electricity.

2. Heat recovery ventilators (HRVs): 

These ventilators capture heat from stale air exhausted from your home and use it to heat fresh replacement air drawn into your home. This can save on heating costs during the winter months. HRVs also dehumidify incoming air in the summer months, reducing humidity levels and cooling requirements in your house.

3. Whole-house fans: 

A switch near the entrance to your home controls whole-house fans; they are normally operated manually but can be installed with a remote control to operate them from outside the house.

4. Inline Exhaust Fan

An inline exhaust fan is much like a conventional exhaust fan but with a twist. Instead of being mounted on the bathroom ceiling or wall of your bathroom, they’re installed in another location, such as a hallway or attic crawlspace, and connected by 6-inch ductwork. The advantage of this type of fan is that we can place it wherever there is access to an outside wall.

The installation process may be a bit more complicated than installing a normal exhaust fan because you will need to run wires up through your ceiling and install special brackets for support of your ductwork alongside the drywall in your home’s crawlspace or attic. If you feel comfortable doing this yourself, you can save money on installation costs.

5. Ductless Fan

A ductless fan resembles a free-standing air conditioner (like one of those tall Octagon units), but it is powered by an external unit and the blower is located directly inside or underneath the fan. 

6. Floor Duct Vents

A floor duct vent is like a ceiling vent except that it is on your floor. You commonly use a floor duct vent for bathrooms in houses with low ceilings or basement bathrooms with slanted ceilings.

The air that is ventilated in this manner will most likely end up in your basement. These ventilation systems can be made even more effective by including both floor and ceiling vents. Because there is no ventilation in the basement, it smells like a sewer.

Keep in mind that installing floor and ceiling vents can be quite costly. On the market, there are a wide variety of air-cleaning devices to choose from.

What you need for the project

The simplest way to vent a bathroom is to run ducts up through the roof. If you’re remodeling and you have access to the roof joists from above, this job is simple. If not, it becomes a much bigger project.

You can run the ducts through a soffit or a gable end, but you’ll have to cut holes in your siding and roofing materials. If your house has aluminum or vinyl siding, you’ll probably have to replace it because most of these materials aren’t designed to be cut after installation.

If you’re up for the challenge, here’s what you need for this project:

  • A drill or hole saw for cutting holes in the ceiling joist and roof, sheathing
  • Use a reciprocating saw or jigsaw to cut holes in the siding and soffit.
  • An angle grinder with a circular saw blade for cutting holes in masonry walls.
  • A power miter saw
  • A 4-in. PVC vent pipe and fittings
  • A length of 4-in. flexible dryer vent hose

How to Vent Your Bathroom With No Outside Access

Installing a bathroom vent fan without outside access is a hard task. Some of the above installation processes will require the help of an HVAC contractor. With this in mind, seek additional help from an HVAC contractor.

1. Make use of a ceiling vent.

A ceiling vent is an excellent way to circulate moisture and steam from your bathroom to the outside via the roof. It will not only help you maintain a beautiful bathroom, but it will also help reduce moisture levels.

A ceiling vent is a unique machine that allows air to escape from the bathroom. It’s a device that allows moisture to escape from your bathroom in the same way that an open window would.

Install a ceiling vent if you want to keep your bathroom from becoming humid or moist. If you can’t do it yourself, hire a professional to do it for you.

We found a light fixture on most ceiling vents. As a result, they can function as both a ceiling vent and a light source.

2. Using a floor duct vent

If your bathroom does not have exterior access and you do not wish to install a ceiling vent, a floor duct vent can ventilate it. What is a duct vent on the floor? A floor duct vent is a specialized gadget that uses floor grates to expel moisture and stale air from your bathroom.

A floor duct vent provides another outlet for unpleasant odors and wetness in your bathroom. We accomplished this by making an aperture and sucking the air out.

While floor duct vents are effective, we believe ceiling vents are more efficient.

3. Utilization of additional ducts

The ventilation issue in your bathroom could be that there is only a one-floor duct, although your bathroom requires two or three. Therefore, if you believe a one-floor duct is insufficiently ventilated, add more.

The same is true if you believe that one of your bathroom’s ceiling ducts is not performing optimally. Simply add one or two additional ceiling ducts to increase ventilation capacity.

4. Use of a fan

Using a fan is perhaps the simplest and quickest way to increase ventilation in your bathroom. This is preferable if you already have a fan at home. Because it just shows that you need to plug the fan in to get it started.

Using a fan will assist you in ventilating your bathroom, particularly if your bathroom currently has a ceiling or floor. This is because the fan will circulate the air in your bathroom, ensuring that any odors quickly dissipate. Therefore, purchase a fan and install it in your bathroom.

5. Vent System inside the Floor

Venting through the roof is impossible if your bathroom is located away from an exterior wall. This is a regular occurrence in bathrooms beneath stairwells.

Contact your HVAC contractor and inquire about the possibility of extending a bath fan through the floor. Here, the plumbing vent goes between the floor joints and exits through the outer wall.

6. Increase the size of Bathroom Ducts

If your bathroom currently has ductwork but lacks adequate ventilation, it’s a pastime to add additional vents. These will help increase the airflow indoors.

7. Enhance your half bath with a recirculating fan

While a recirculating fan does not vent the air, it passes it through an air filter in your bathroom, ensuring that any odors are removed.

A recirculating fan is an ideal solution as there are no built-in showers in half baths. This shows that the moisture content is quite low.

8. Commercial Ductwork Installation

If you live in a small apartment that is part of a bigger structure with high ceilings, you will need to hire a contractor to install commercial ducting to unify the airflow. This will improve the bathroom’s airflow.

9. Dehumidifier for Bathroom

A bathroom dehumidifier is comparable in cost to a ductless fan. However, dehumidifiers are the most effective method of removing moisture from a bathroom that lacks a vent.

When a humidifier detects an abnormally high level of humidity in the air, it immediately turns on and takes care of the problem.

While dehumidifiers are an excellent option for removing moisture from the air, they will not eliminate any offensive bathroom odors.

10. Moisture-absorbing Plants

Certain plants have been capable of absorbing moisture from the air.

English ivy and Boston ferns, among others, can help reduce the humidity in your bathroom while also adding elegance.

It’s difficult to determine how much moisture these plants can extract from the air and, thus, how successful they will be in specific situations.

11. Maintain an Open Door

Simply keeping the door open is one of the simplest methods to vent a bathroom with no outside access.

Similarly, to a vent, an open door allows damp air to escape rather than being trapped in your bathroom. While it is convenient, an open door is not the most effective method of ventilation.

Leaving a bathroom door open at all times allows for the spread of undesirable bathroom odors throughout your home.

12. Make an appointment with a professional

If you believe that ventilating your bathroom on your own will be too much labor and you are concerned that anything may go wrong, contact a professional. We are used to it dealing with a variety of scenarios and it can ventilate virtually any location, including the basement. This is because they possess the knowledge and instruments necessary to install most ventilation systems without help.

The only disadvantage to hiring a professional to install fresh ventilation is that it is frequently costly. Therefore, contact a professional to install or upgrade your bathroom ventilation only if you are certain you can not complete the job yourself.

Potential Safety Hazards

Before you drill, consider the safety hazards. You must watch out for live electrical wires, plumbing lines, and gas pipes in your walls. Always shut off the power to your home before working on electrical wiring and shut off your water supply before working on pipes. Make sure the area is well-ventilated to avoid inhaling fumes from a gas leak or dust from drilling through the wall.

Marking the Wall

Next, you must determine where the exhaust fan will be in relation to your bathroom window. The fan needs to be positioned above the window so we can vent upwards and out of the house. If it is not possible to locate the fan above the window, you might have to install it somewhere else in the bathroom, such as above the door or on an outside wall that has easy access for venting. If a window is not present in your bathroom, drill a hole in an exterior wall large enough to accommodate your vent pipe.

Drilling Through Your Wall

Drill through one side of the wall where you have marked its location with a 1 1/2-inch hole saw. Drill again through the other side of the wall at exactly the same spot so that you have two holes:

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Sure, you’re a seasoned DIYer. You can run pipes in your sleep. But venting in a bathroom? That’s a whole different beast, isn’t it? Whether you’re installing a new bathroom or just need to replace an old vent, figuring out how to properly vent the space can be challenging. And if you don’t do it right, you could end up with mold or mildew growth, or worse, cause structural damage to the home. With our simple steps, however, you’ll be able to get the job done right every time.

Well, that’s everything. Thanks for reading the article about how to vent a bathroom without outside access. Hopefully, you picked up something useful and learned something new along the way. Maybe you found a few mistakes in my writing too, and if you did, be sure to let me know about them.