Can Mosquitoes Come Through Bathroom Exhaust Fan?

Mosquitoes are tiny flying insects that can enter the bathroom through different sources, such as exhaust fans, windows, or other openings outside the house.

Can Mosquitoes Come Through Bathroom Exhaust Fan? Mosquitoes can come through the exhaust fan because of the moisture and condensation, dust and dirt accumulation, light, and cracks in the vents and ducts. You can prevent mosquitoes from entering this place by installing vent screens, fixing the cracks and leakage, cleaning the exhaust fan, and spraying insect repellent.

They live indoors and outdoors and can survive on human and animal blood. For example, they can enter the bathroom and thrive there for almost 3-4 weeks, depending on the temperature, moisture, and species. 

Why would mosquitoes come through the bathroom exhaust fan?

Mosquitoes can come through the bathroom exhaust fans and the vent ducts because of the following reasons.


They can survive in moist and humid places for many weeks, and the female mosquitoes can lay their eggs in damp places to increase their breeding.

When the humidity level in the air inside the bathroom is high, the moisture inside the exhaust fan vents and ducts causes condensation inside the pipes and fan.

The mosquitoes cannot enter the running fan; therefore, the chances of their entrance increase at night when you turn the fall off and go to sleep.

They can enter this place and find moist and damp places to hide until they find their host to get the food. You can find them around the toilet, bathtub, and sink where the moisture level is high.

They cause different diseases, depending on the species which bite you, and they can multiply to hundreds if you do not remove the source of their survival and entrance into the bathroom. 

Dust and dirt accumulation in vents

Dirt and dust are one of the reasons to attract different bugs and insects, and they can find their way into the house if you have unclean vents that open outside the house. 

Dirt can accumulate in the vents of the bathroom fan, which also causes mosquitoes to come into this place from outside, such as the backyard or grounds.

The unsealed ducts collect moisture and dirt and dry to form a dirty grime to attract the mosquitoes to gather at this place.

The dirty vents can stop the airflow, and moisture can accumulate there, which causes the insects to come and stay until they find a chance to enter this place.

Attracted to light

Research shows that these parasites are attracted to light, such as you often see these tiny insects in the room around the yellow light in the bathroom if they manage to enter there.

The light from the unsealed vents causes the mosquitoes, especially the day-biting female insects to enter the ducts into the bathroom.

They use the light in the bathroom to navigate and regulate their activities. For example, they can fly inside the vents and enter the house when the exhaust fan is not on.

Cracks in vents and ducts

The exhaust fan that is installed on the bathroom wall, draws air from outside through the ducts and vents, which causes these insects to enter through them if they get cracked from outside.

They can enter the vents’ crack openings and end up in the bathroom. They can sense the carbon dioxide you exhale and fly to get their food biting your skin.

The damaged dampers and the cracked components of the exhaust fan make it easy for these parasites to enter and thrive in this place.

How to mosquitoes from entering through the exhaust fan?

People use different methods and hacks to prevent mosquitoes from entering through the exhaust fan in the bathroom, and some methods are listed here.

Install vent screen

Vent screens are metal or plastic fine mesh, which can restrict these parasites from entering the exhaust fan vents and ducts into the bathroom.

The metal meshes are more durable and functional, especially the stainless steel mesh, as they are finer and can avoid small insects like mosquitoes coming into this place.

Some vent screens are made using a waterproof grille that prevents rainwater and moisture from entering the vents.

I have done this task myself, as it is easy to install the screen without wasting money on the labor cost if you have the experience to do it.

Firstly, remove the exhaust fan cover by removing the screws using a screwdriver, but different models of the exhaust fan require different tools to remove the plate, such as some have tension brackets.

Now, I squeezed the two brackets, pulled the cover out of the slot, and removed the cover plate of the fan down. You can select a high-quality vent screen from a nearby shop and get some scissors to cut the screen to fit on the fan cover.

You may need an adhesive or caulk to glue the screen on the cover. I prefer using caulk because it is easy to remove when you want to replace the screen.

I cut the screen into a square shape of the same size as the cover and pinned a hole in the center to reattach the screw with the fan. Then, you can apply the caulk around the screen and the edges of the fan cover. 

Make sure to level the caulk with your fingers from the corners and around the sides to fix it on the cover properly.

Let the caulk cure for 15-20 minutes, then place the cover back in its position. It is better to vacuum the exhaust fan if you notice dust and dirt around and inside the plate.

Carefully attach the cover to the bathroom exhaust fan and tighten the screw using a screwdriver, and you can apply the caulk around the plate if it does fit firmly in its location to prevent the insects from entering there.

Regular fan cleaning

Different insects and bugs are attracted to dirt and unhygienic places, which causes diseases to spread through these insects.

It is better to clean the vents and ducts after a few weeks to avoid dirt accumulation, which attracts them into this place. 

Take a soft cloth and clean all the fan parts by removing the exhaust fan cover. Clean the blades and the air filter using a cleaning solution without scrubbing it harshly. 

I often use a brush to thoroughly clean the inner parts and the vent cover to remove the grime and dirt buildup. The chances of mosquitoes decrease if you keep the exhaust fan clean and secure.

Fix the cracks or leakage

The cracks and leakage in the ducts and outside vents cause these insects to attract to this place, and they find their way o enter the bathroom.

Sealing the ducts and fixing any cracks or leakage in the exhaust fan is better to reduce the chances of mosquitoes coming through them.

The leakage in the vents causes moisture and water to drip from the fan, which is an inviting place for many insects and bugs.

I have selected an exhaust fan with a back damper, which controls the airflow and restricts these tiny creatures from entering the bathroom. 

Spray mosquitoes repellent

Different smells, chemicals, and oils can repel mosquitoes from entering the bathroom if you spray them in different corners and in the places from where they can enter.

Neem oil, citronella oil, lavender, basil, marigold, and other high-fragrance plant oils can repel these insects because of their sharp odor.

You can spray them at night or during the day if you are not allergic to any of the oils, keep the mosquitoes at bay and apply different pest control products if the infestation is severe after consulting a professional.

Keep the bathroom clean

Cleaning is essential because dirt and smell can cause mosquitoes to come and thrive in these places to multiply into hundreds.

It is better to turn the bathroom exhaust fan on after a shower or bathe and use the toilet to remove the excess moisture and smell from this place.

You can place different plants that can repel these insects from entering the bathroom and apply a disinfectant, which keeps the germs, bacteria, dirt, and smell away.

Related Articles:

What would you do when rats come up in your toilet?

How to Stop Bugs From Coming Up The Shower Drain?