Why is The Bathroom Exhaust Fan Blowing Air Down? Find Out!

It’s a warm, humid day and you are about to take a bath to start your busy day. But the bathroom is all wet. So you turn on your lifesaver exhaust fan. But today is an unlucky day! The exhaust fan is not functioning properly, rather it is blowing air down!

So you are left with the question, why is the bathroom exhaust fan blowing air down?

Several factors can cause this problem. To start, your backdraft flapper could be stuck. Then, the vent pipe might be clogged with dirt. There are also the odds of defects in the vent pipe. Besides, you can not neglect the chances of a faulty connection. The grates can make the fan blow air down too!

But there is a lot more information. Don’t get tensed. We’ve made an elaborate discussion on finding and solving the problem only for you! 

So, let’s start.

Reasons Behind The Bathroom Exhaust Fan Blowing Air Down

Air must blow in the right direction through the exhaust fan. If it blows in the wrong direction, it won’t serve its purpose. There are several reasons for which the exhaust fan might blow air in the wrong direction.

Vent Pipe is Clogged with Dirt

A vent pipe is a path through which the exhaust fan will expel the air from the bathroom. Since it contains dirt and moist air, often it gets dirty. As a result, air won’t pass through the vents and you will feel like the air is flowing in the wrong way.  An accurate vent size in the bathroom is very necessary for the bathroom. 


The grates are the covering over the fan. Check if the grate is clean and not resisting the airflow. If needed detach the grates and clean them. Most grates are attached by screws. Some new models use tension clips that are easy to remove.

The Backdraft Flapper is Stuck

The backdraft is an essential part of the complete exhaust system. It is an essential part which works for expelling the air.

See also  How to Clean Bathroom Mold? (6 Cleaning Methods to Try!)

The point where the fan and the vent attach is used to fit the flapper. It is also attached at the point through which the vent pipes expel air. In modern sophisticated exhaust fans, there are even two flappers at two points.

This flapper is fixed in such a way that it allows the air to flow outside the bathroom. But it blocks the air that flows towards the bathroom. In this way, it prevents the exhaust fan from blowing air down. But if the flapper is stuck the air might blow down to the bathroom.


As we have told before, the flapper plays a very significant role to restrict the air flow inside the bathroom. So the flapper must be checked thoroughly. Make sure that the flapper is not open all the time. If it’s open all the time, air will pass both ways. If it’s stuck, clean it well. Sometimes, you may need to replace the flapper if it is beyond repair.

Formation of Lint on the Fan

The fan rotates to expel the air. If the fan isn’t cleaned for a long time, lint will surely form on the blades of the fan. This lint formation will impede the airflow. As a consequence, the fan might blow the air down.


Check the fan blades. Clean it to make sure it rotates in the right manner. You must make sure whether the fan blades are tight or loose. If they are loose, that might be the reason behind the wrong airflow.

Wrong Connection in the Motor

You might face this problem when you install a new exhaust fan in your bathroom. There are positive and negative terminals in the motor of the exhaust fan. If these terminals are connected to the wrong wires the fan will rotate in the opposite direction. Thus, it’ll blow air down. 

But there’s good news for you. New models of exhaust fans are built in such a way that they will rotate in the right direction irrespective of the connections.

See also  How To Remove Dry Paint From A Bathroom Sink?


Do this only if you have installed a new exhaust fan. Also if you’ve recently repaired the fan after detaching its connections, check the connections again. Alter the terminals of the wire and check if the problem is solved.

Damaged Vent Pipe

There is always a chance that the vent pipe is damaged. Everything has a lifetime. So naturally, the vent pipe will deteriorate after a long use. The damaged vent pipe will block the passing air. When the air won’t be able to go through the pipe, it will come back to your bathroom.

Without proper ventilation, there are chances of mold formation in different places in your bathroom. Then you have to look for solutions to clean the mold on your bathroom popcorn ceiling.


The solution is easy if your vent pipe is dirty. Clean it thoroughly and your problem will be solved. But the problem becomes complex when the vent is damaged. In such a situation you must replace it. Buy a vent compatible with your system and replace it. 

We have made a list of vents that you can buy to replace your damaged vent. Try this for your convenience.

Product-1: AC Infinity Flexible 4-Inch Aluminum Ducting.Hon&Guan 3 inch 16 FT Long Air Ducting
Product-2: Hon&Guan 3 inch 16 FT Long Air Ducting. iPower GLDUCT4X8C.

Use these products as a replacement. We hope these products will give you a great experience.

Once you have identified the problem you have to find the solution as soon as possible. Or else you might have to install the bathroom fan in the wall. Then you’ll have to spend an amount to compensate for the cost of remodeling the bathroom fan.

Follow our guidelines to solve the problem at ease. Also, our given process will enable you to solve the problem without any hassle. 

Pointers to Avoid Exhaust Fan Difficulties

Prevention is always better than cure. It is good to take care of the exhaust fans so that it doesn’t deteriorate. 

See also  How to Clean Old Bathroom Floor Tiles? [Everything You Need to Know]

We have provided you with some tips to take care of your exhaust fans below.

Clean the Fan Regularly

The exhaust fan deals with dirty and moist air. So it’s important to clean them regularly. Otherwise, a layer of dirt will form on them. This layer of dirt is pretty strong. So you will face difficulties while removing the dirt. So clean them frequently and save both your labor and money.

Oil the Exhaust Fan Parts

The fan is a mechanical device. So, oil its parts regularly. This will help the exhaust fan to run smoothly. Moreover, oiling will prevent corrosion. 

Avoid Unnecessary Use of the Fan

Don’t keep the fan running. It is best to use the fan after using the bathroom. This will also save a fortune on the electricity bills. The life-time of the fan will increase if you run it in a rountined way. 

These tips will be helpful to prevent the exhaust fan from blowing air down. Make sure you use them to get a good result!


Question: What is the process of checking that the exhaust fan is blowing air correctly?

Answer: You can use tissue paper or a gaslighter. Simply hold the tissue paper in front of the fan. If it gets stuck on the grate, the fan is working fine. The gaslighter process is like the tissue paper process.

Question: How important is Exhaust Fan cleaning?

Answer: It is very important to clean the exhaust fan. Make sure you make the fan blades free of moisture. Also, the vents get dirty pretty soon. So clean them regularly.

Question: How long does an exhaust fan run?

Answer: A bathroom exhaust fan gives a service for more than ten years. But if you take care of it regularly you can increase its longevity and it may last for more than 15 years.


This is everything in detail about the bathroom exhaust fan blowing air down. We have discussed every possible scenario. The solutions to every scenario are given in the easiest way.

We expect your problem will be solved without any hassle. Don’t feel shy if you face further problems. Comment below about any of your confusion!.

Leave a Reply

Your email address will not be published. Required fields are marked *