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Bathroom Exhaust Fan Not Removing Steam?

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Last updated on August 14th, 2022 at 01:28 pm

Most people would rather use extra-hot water in their baths; this may create tons of steam in your bathroom. Nevertheless, bathroom fans are designed to remove this steam from the bathroom and make it more comfortable for you.

However, your bathroom fan may not be efficient in doing this function, or it may stop doing its job, and you may be wondering why.

Your bathroom exhaust fans may not remove steam for several reasons. These range from the strength of the fan to how it is used. Also, other factors such as the size of the duct or the availability of a vent affect the efficiency of the bathroom exhaust fan. Nevertheless, most problems that arise from excess moisture come about because the fan does not run long enough.

Do Bathroom Exhaust Fans Remove Steam?

The primary function of bathroom exhaust fans is to remove steam and moist air from your bathroom and send it outside the home. However, these fans also dry out the bathroom even after showering and moving moisture out of the building envelope.

In the past, home designers built houses without totally considering the insulation, so moisture problems in the house weren’t common. However, due to the increased ventilation which modern houses are designed with, it gets hard for steam and air moisture to escape.

Bathroom exhaust fans pose great benefits to the entire well-being of the house. Because most bathrooms are small and have tiny, easy-opening windows, ventilation is pretty minimal.

Therefore, bathroom exhaust fans are the only escape methods for the steam which comes up from the hot bathwater.

Now, if the steam does not have anywhere to go, it settles and condenses on every surface in the bathroom. Consequently, this produces mildew, mold and all kinds of bad odors within a short time.

However, it peels the wallpaper in the long run, rots drywall and warps wood trimmings and furnishing.

However, if the ventilation and air removal which your bathroom exhaust fan provides are high enough, this problem will be solved.

Additionally, bathroom exhaust fans and kitchen exhaust fans share similar functions. So, installing both in your home works wonders in optimizing the air quality in your house.

Why is My Bathroom Fan Not Removing Steam?

At a certain point, your bathroom fan may not remove steam. This may be due to several reasons such as the bathroom door’s gap, the power of the fan, the presence of dirt in the fan, and some other factors.

Sometimes, you may notice that your bathroom fan is not removing steam; this causes moisture to build up in your bathroom. Resultantly, you would observe the growth of some organisms, such as molds and mildew.

Nevertheless, certain factors cause bathroom exhaust fans to not be able to remove steam; some are:

1. Small Bathroom Door Gap

For your bathroom fan to function properly, there must be enough incoming air to replace the one going out. Therefore, if there is no gap under the bathroom door to allow for air passage, fresh and clean air cannot flow in the room easily.

If the door is closed and the bathroom fan is on, the exhaust fan will have to fight to draw air through small openings. This occurrence would greatly reduce the efficiency of the bathroom exhaust fan.

The easiest way to test if the gap is sufficient is to close the door quickly. Thus, if there is air resistance while closing the door, the gap isn’t big enough.

Most often, bathroom doors are installed correctly during the construction of the house. However, later renovations and repairs mess with the correct state of affairs.

2. Bathroom Fan is Not Vented

Vented bathroom fans easily move steam out of the building. However, ductless fans circulate air through a carbon filter, and this does not remove steam.

In many instances, ductless fans are passed on as being able to remove moisture; however, this is false. Also, this might be the case if you recently moved into a new apartment.

3. Bathroom Exhaust Fan is Not Powerful Enough

If the bathroom fan is not powerful enough to exhaust the moisture, steam accumulates in your bathroom. Your bathroom fan should be able to achieve eight air changes per hour as the ‘Home Ventilating Institute’ recommends.

Also, remove the cover of your exhaust fan to unmask the model number. Now you can use the number to calculate the cubic feet per minute (CFM) which the fan covers.

4. The Fan is Turned Off Before it Should be

I used to think that I was supposed to run the bathroom fan only when I took a shower; however, I was wrong. Now, many people make the same mistake I made. This is because there will be tons of moisture in the air after showering. Therefore, you should run the fan at least 30 minutes after you have taken a shower.

By calculating the moisture level in my bathroom, I understood that it takes over one hour for the moisture to drop after I bathe. Additionally, you should use a humidity-controlled switch for kids as they most often forget to use the bathroom exhaust fan.

5. Dirty Bathroom Fan

When dust and lint build up in the bathroom fan, it limits the quantity of air that passes through the duct. This makes the exhaust fan very much inefficient.

Because the fan blades become moist when removing steam, the dust present in the air deposits on them and cause problems.

Thus, it is highly advisable to clean your fan once in a while or clean it when you move into a new place.

6. Extremely Small Duct With Many Turns

The size of the duct and the number of turns it possesses increase the overall static pressure of the duct. Therefore, small ducts with higher static pressure make it hard for bathroom exhaust fans to push out air.

Now, using a small, complicated duct coupled with a fan with low strength, the airflow will not be enough to remove moisture efficiently. Therefore, always make sure to obtain ducts with large spaces which allow for effective removal of moisture.

How do I Test My Bathroom Exhaust Fan?

You can test your bathroom exhaust fan using the toilet paper test; this test uses the principle of suction to tell the efficiency of a fan.

Most people assume that their bathroom exhaust fans are functioning properly because of the noise they make. However, this is not always the case because a fan’s noise does not always represent the work rate.

Well, the most popular method to test a bathroom exhaust fan is the toilet paper test. You should take two pieces of toilet paper and put them up in the fan. If the fan sucks the toilet paper holder and stays attached, the can work pretty fine.

However, if the toilet paper doesn’t stay attached to the fan, the fan is doing a bad job.


Your bathroom exhaust fan may not be effective in doing its work. Note that there are several reasons which may cause it to be so.

Nevertheless, getting to the root of the problem and creating solutions is always something easy to do.

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