There are a lot of misconceptions about exhaust fans out there. Exhaust fans are one of the most underrated—and misunderstood—features in a home. They quietly remove moisture, odors, and stale air, helping to improve indoor air quality and prevent long-term structural issues. Yet despite their importance, many homeowners have misconceptions about how they work and what they’re designed to do. These misunderstandings can lead to improper installation, reduced performance, and even hidden damage to the home. Let’s clear the air—literally and debunk some common misconceptions about exhaust fans.
Misconception 1: Exhaust fans are only for removing odors.
Yes, exhaust fans remove odors, but their primary purpose is to remove humidity and moisture. In bathrooms, excess moisture from showers and baths can lead to:
• Mold and mildew growth
• Peeling paint
• Damaged drywall
• Premature wear on fixtures and finishes
Reality: Exhaust fans maintain healthy humidity and air quality.
Misconception 2: Exhaust fans don’t need to be vented outside.
Some homeowners (and unfortunately even some contractors) believe that venting an exhaust fan into an attic or wall cavity is fine. But what you’re actually doing is dumping warm, humid air into a confined space, where it can condense and cause:
• Mold growth
• Wet insulation
• Wood rot
• Attic structural damage
Moisture doesn’t disappear—it relocates.
Reality: Exhaust fans must be ducted to the exterior, NOT into attics, crawlspaces, or wall cavities.
Misconception 3: Leaving the door open does the same thing.
Leaving the bathroom door open after a shower may help a little, but it doesn’t quickly or effectively remove moisture. Exhaust fans create a controlled, directed airflow that pulls moisture out of the room and out of the house.
Reality: Natural ventilation is not a substitute for mechanical ventilation.
Misconception 4: Bigger fans are always better.
A fan that’s too powerful for a small bathroom can actually cause problems:
• It may create uncomfortable drafts.
• It might pull conditioned air out of the house too quickly.
• It could overload ductwork, leading to noise and reduced efficiency.
Correct sizing is everything. A fan should be appropriately rated based on the room’s square footage and usage.
Reality: Proper sizing matters more than power.
Misconception 5: Exhaust fans only need to run while I’m in the room.
Moisture remains in the air long after the shower is off. Turning the fan off too soon traps humidity in walls and ceilings. A good rule of thumb:
Run the fan for at least 20–30 minutes after showering.
Even better? Install a humidity-sensing fan or a timer switch.
Reality: Exhaust fans need time to do their job completely.
Misconception 6: Exhaust fans don’t need maintenance.
Dust, lint, and debris build up on fan blades and in ductwork, reducing airflow and increasing noise. A clogged fan can’t exhaust moisture efficiently. Simple yearly maintenance (vacuum the grille and fan blades) keeps performance high and noise low.
Reality: Like any mechanical system, fans need periodic cleaning.
Misconception 7: Exhaust fans cost too much to operate.
The energy efficiency of exhaust fans has come a long way. Choosing an ENERGY STAR® certified model ensures that the energy usage is low. Many fans on the market today use between 10 to 40 watts of energy. The national average cost for a kilowatt of electricity is $0.18. Here are some calculated costs:
• Exhaust fan operating 3 hours/day: between $2 - $8 per year
• Exhaust fan operating 24 hours/day: between $16 – $70 per year
When you compare the costs of repairs, mold remediation or other problems caused by not using an exhaust fan, the cost to operate is low.
Reality: The benefits of an exhaust fan far outweigh the cost of energy needed to power them.
Final Thoughts on Misconceptions about Exhaust Fans.
When installed and used correctly, exhaust fans protect your home from moisture damage, improve indoor air quality, and reduce the risk of mold. Yet when misunderstood or neglected, they can contribute to the very problems they’re meant to prevent. If there’s one takeaway, it’s this: Exhaust fans are not just conveniences—they are essential components of a healthy home.
Ensure your fans or being used, use them for the correct amount of time, maintain your fans, check your ducting and make sure they’re vented outdoors—your home will thank you. For more information about Air King’s energy efficient exhaust fan solutions, visit airkinglimited.com
