Should Bathroom be Closed or Open when Exhaust Fan is on?

Should Bathroom be Closed or Open when Exhaust Fan is on?

The bathroom door should be closed when the exhaust fan is on if your bathroom is large with a window and a good opening at the bottom of the door. But if your bathroom is small, open the door while the exhaust fan is on to enable it to pull enough air from the outside.

The bathroom has always been an important place in every building that needs to be taken care of. First of all, there is no residential building without a room for a toilet and bathroom. Some structures may have a toilet in a separate room and a bathroom in another room.

However, most modern houses include both the bathroom and the toilet inside the same room. Those whose bathroom is big enough also have a section where their clothes are hanged, where they can dress and apply some makeup. All these prove how important a bathroom is in every household and if we should have a bathroom in our house, maintaining it should be our utmost priority.

Exhaust fans always go pari passu with the bathroom simply because of the vital work it does inside the bathroom. As we all know, we poop, bathe, urinate, wash, etc., inside the bathroom, and all these involve water, which means that the bathroom has a lot to do with water and moisture. Moreover, the bathroom is usually a small room except for those whose bathroom is large. No matter how large your bathroom is, it will not be bigger than your bedroom.

Should Bathroom be Closed or Open when Exhaust Fan is on?

The bathroom door should be closed when the exhaust fan is on if your bathroom is large with a window and a good opening at the bottom of the door; the fan will pull air from the bottom of the door, the cracks, and the opening from the window. On the other hand, if your bathroom is small with a tiny space at the bottom of the door and no window, you are advised to open the door while the exhaust fan is on so that the fan can be able to pull enough air from the outside.

Most bathrooms do not have a window. Those that have a window in their bathroom do not open it for one reason or the order. I don’t open my bathroom windows because they are positioned outside. I don’t want a situation where I will be having my bath, and someone will be outside peeping at me.

Nevertheless, if I don’t open my windows, I will have to need a means by which I can easily take care of the moisture and humidity in the bathroom. That is where a bathroom exhaust fan comes into place. Having a small or large bathroom without a window and exhaust fan will take a longer time to dry the wet bathroom floor, coupled with the fact that you have to be struggling with humidity.

Opening or closing a bathroom door when the exhaust fan is on depends on many factors such as the size of the bathroom, the capacity at which the exhaust fan runs, the amount of air that enters the bathroom through the opening at the bottom of the bathroom door, and many more.

For example, I have a master bedroom. My toilet happens to be inside my bedroom. I don’t have an exhaust fan in my bathroom, but I have a window that I don’t open. What I do is I always open my bathroom door a little bit after showering to enable the floor to dry and to take care of the humidity.

If there is anything we should avoid in the bathroom, it is humidity. Not taking care of moisture inside your bathroom may lead to excessive mold. Trust me; you do not want mold in your bathroom. It is horrible for your health, and it may cost you money to get rid of. The question now is, what is the function of a bathroom exhaust fan?

What is a Bathroom Exhaust Fan?

A bathroom exhaust fan was specifically meant to be used in the bathroom to get rid of stale, humid, and impure air from the bathroom. It performs much duty, but the major function is to remove steam, foul odor, and many more from the bathroom.

Functions of Bathroom Exhaust Fan

Below are the importance and functions of the exhaust fan. It is also the reason why you should put an exhaust fan in your bathroom.

1. Smells

The first function a bathroom exhaust fan does in your bathroom is to remove the bathroom’s odor. It is the fastest way of removing any form of smell from the toilet. Whether the smell is coming from a poop, etc., the exhaust fan will take care of it. Trust me; you don’t need to perceive your poop while using the toilet.

While some argued that exhaust fans do not stop humidity in the bathroom, especially when the bathroom door is closed while taking their bath, I’m telling you that it will help control the moisture. While bathing, some said that they turned on their exhaust fan yet still had humidity in the bathroom.

They forgot that it might be that the size of their bathroom is larger than the exhaust fan. If that is the case, the fan will not be too useful. There are many things to consider before buying a bathroom exhaust fan; we will discuss that later.

2. Mold Prevention

An exhaust fan helps keep the bathroom dry at any time. Keeping the bathroom dry will prevent excessive smelly and dangerous mold and mildew proliferation in the bathroom. 

3. Paint and Building Material Preservation

Too much humidity inside the bathroom can cause your bathroom paint to peel. Besides that, excessive moisture in the bathroom will cause you always to clean the tiles, bathtubs, etc. Even if you like cleaning, you don’t want to be doing that every day because you don’t have an exhaust fan. So putting an exhaust fan in your bathroom will help.

4. Extra Light

Most bathroom exhaust fans come with light; buying such a type of fan will help conserve space for you. Meanwhile, it can also add extra light to the bathroom.

5. Built-in Heater

Some bathroom exhaust fans come with an inbuilt heater. This will be very handy during cold times; you can turn on the fan while showering and let the heater warm you up.

6. During Cleaning

The bathroom fan is convenient when cleaning the bathroom. Some bathroom cleaners were made with chemicals that are very bad for the body system when inhaled. Inhaling such cleaning products while cleaning the bathroom is very risky, especially if you are pregnant. But if you have an exhaust fan in the bathroom, it will help keep your bathroom fresh.

Things to Consider when buying a Bathroom Exhaust Fan

You need to know the size of your bathroom, the square footage, and space when buying an exhaust fan for your bathroom. Doing this is vital because every bathroom exhaust fan comes with its size and is rated by its ability to move air in cubic air.

If your bathroom is small, it’s better to buy smaller fans because they generate less CFMs. But if you have a large bathroom, go for the bigger fan. It is crucial. Moreover, you need to know the environmental condition of your area, and the duct size the bathroom exhaust fan will be connected to

Is Bathroom Exhaust Fan More Effective with the Bathroom Door Closed, Open, or Cracked?

The effectiveness of a bathroom exhaust fan depends on several factors. They are:

  • The size of the bathroom
  • The size of the bathroom exhaust fan you have
  • Size of the gap when cracked. 
  • Size of the bathroom 
  • The size of the gap at the bottom of the door
  • The capacity of the fan
  • The temperature of the bathroom air compared to that of the adjoining rooms
  • The humidity of the bathroom air compared to that of the adjoining rooms.

When your Bathroom Door is Closed

If you close your bathroom door while your fan is on, the fan will pull more air from the gap at the bottom of your bathroom door. Since the bathroom door is closed, the system’s pressure drop will increase, thereby moving less volume of air in the bathroom.

When the Bathroom Door is Cracked

Cracking your bathroom door will allow more air into the bathroom while the exhaust fan is on. This is much better than closing your bathroom. With a cracked door, even if the door is entirely closed, the fan will still be able to get more air to do its job.

When the bathroom Door is Open

If the door is open while the exhaust fan is on, the fan will pump more air volume into the bathroom to do its job. The only downside of this is leaving the bathroom door open may distribute unpleasant odor from the bathroom into the adjoining rooms. 

However, from the explanation above, we’ve come to understand that opening the bathroom door while the exhaust fan is on is the best thing to do. However, you need to make sure your bathroom is clean to prevent the circulation of unpleasant odor to the house’s adjoining rooms.

How Long Should I Leave Bathroom Exhaust Fan On After Shower

Leave your bathroom exhaust fan on for 20 to 30 minutes after bathing, depending on the size of your bathroom. If your bathroom is large, you have to leave it on for at least 30 minutes. If it is a small bathroom, you have to leave it for at least 15 to 20 minutes.

However, some bathroom exhaust fan comes with a timer; you can experiment with the time on the fan to know the exact time it was able to do its job so that anytime you finish taking your bath, you can just set the time and let it do its job.


To know if your exhaust fan works well when the door is closed, you need to do some experiments. What you have to do is to turn on the fan, close the bathroom door, and shower. If, after showering, you did not see any fog in your bathroom mirror, then you don’t need to open the door when it’s on. However, if otherwise is the case, you can open the door to enable the fan to work best for you. Don’t forget to leave the bathroom exhaust fan on while showering.