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Don’t Forget the Vent Fan in Bathroom Renovations

Don’t Forget the Vent Fan in Bathroom Renovations

Bathroom renovations are a good time to put your major wrongs right. You can take care of leaky pipes, subpar wiring, old grout, and bad layouts. With so much going on, it is easy to forget about one thing: the vent fan.
A vent fan draws air from inside a room to the outside via a duct mechanically. It literally sucks out the air using a simple device. You can put one in your bathroom at any time. Bathroom renovations just make it so much easier, so you should take a note of it in your plan.


The most obvious use of a vent fan is to get rid of bad smells. That alone makes it essential for any bathroom in the home. However, that is not actually its most important use. No, the real reason you need a vent fan is to suck out warm, wet air from the bathroom.
Bathrooms tend to be humid all the time. The air in the bathroom, especially one that has no windows, is usually moist and warm. This is true even for a powder room that does not have heated showers. Water is ever present in a bathroom, so the inside air tends to be wetter. Since most people like to keep bathroom doors closed, it stays wet.

You want to do this because high humidity in a dark, closed space encourages the growth of mildew and mold. If your bathroom smells musty, it probably means you have no vent fan in there and mildew and molds have already taken up residence. That means more work for your bathroom renovation contractor.

Aside from harboring little mold gardens, prolonged exposure to moisture can also damage any wood in your bathroom, such as the ceiling and door. If you have wallpaper in there, you can expect it to start peeling off. Bathroom fixtures may also take a beating, especially if they are prone to rust and corrosion.

The building codes in some areas actually require a vent fan in bathrooms as part of keeping the bathroom safe and healthy. The code may specify the requirements for the vent fan depending on the size of your bathroom. You should check the local building codes for any regulations you need to follow regarding bathroom vent fans. Discuss it with your contractors to make sure they know about it.

How it works

The vent fan works pretty much the same way as any fan. The blades of a fan typically tilt at an angle of 12 to 15 degrees. When the blades of a fan move around, it draws air in and then sends it out. The speed of rotation, angle of the blade and the number of blades will determine how strongly the fan can draw air in. When the vent fan is in use, it continually pushes the air drawn in along the duct into the open air through a hole cut in the wall or roof.

Technical tips

Even if there are no legal requirements for your bathroom vent fan, you still need to know the type you should get for your bathrooms. Here are some technical tips to guide you.


CFM stands for “cubic feet per minute.” It is expressed as cu ft/min. It measures the speed of the airflow in or out of a room or space. When used concerning a vent air, it refers to how fast it can suck air out of your bathroom. Obviously, how much CFM you need will depend on the size of your bathroom. As a rule of thumb, if your bathroom is less than 50 square feet, you only need a vent fan at 50 cu ft/min. If it is between 50 and 100 square feet, you will need one at 1 cu ft/min per square foot. This means that if your bathroom is 90 square feet, you need a vent fan at 90 cu ft/min.
If you have a bathroom with a high ceiling (more than 8 feet high), you may have to install a vent fan with a higher CFM. Alternatively, you can put in more vent fans.


Most bathrooms have vent fans over the bathroom door to catch escaping smells before it can get out. However, it is actually better to put it over as near to the tub or shower stall as possible, but not so that anyone standing in water can reach it. If you can do this, make sure the vent fan is approved for “wet” conditions.

Electrical codes

Whether your area has specific building codes for vent fans or not, you still must follow the National Electrical Code for the bathroom. The code specifies that a bathroom should have a separate circuit for the light and vent fan, possibly a blower-heater-light combo, from the outlet circuits servicing hair blowers and the like. The switchers should be grounded to avoid possible shock.


Vent fans are important for any bathroom, so make sure you remember to put them in your bathroom renovation plans at the very start. A reliable contractor would know all about the need for vent fans, and Fairfax Kitchen Bath fits that bill.
Fairfax Kitchen Bath services the DC, MD and Northern Virginia metropolitan areas. We are a Class A, licensed and insured contractor, registered in the Commonwealth of Virginia. You can ask about vent fans with our designer when we come to discuss your initial cost estimate.
We guarantee you will love it for life. We sell only top quality products for all your bathroom renovation needs manufactured by leading brands in the industry.

When you contract with us, you can be sure you will get a quick turnaround on your products, and receive it much faster than ordering what you need from big box stores. We specialize in bathroom renovations, including vanity tops, fabricating them to specifications, and installing them within budget and on time.

We carry the products you need for your bathroom renovation, including sinks, faucets, natural and engineered stone slabs, shelves, tiles, backsplashes, knobs and pulls, hardwood flooring, and cabinets,. We carry only the top brands for these products, such as Schrock Cabinetry, Silestone, Blanco, Kohler, and Mosaic Décor.

You can see the products before you buy so you can decide for yourself if the quality is what you expect. We have a showroom in Fairfax, Virginia, which houses all our products, including actual granite, marble and engineered stone slabs from which you can choose.
Our products come with manufacturer warranties that ensure your satisfaction with the quality and installation.
Contact us today to get a free quote for a budget-friendly bathroom renovation project.

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Picture of Sam Kazanci <br/><span id="position">Owner</span>
Sam Kazanci

Sam Kazanci is the owner of Fairfax Kitchen Bath Remodeling. He has experience to build and remodel the kitchen and baths with his team and the author of fkb blog: You can find Sam on LinkedIn and Twitter.