If you’re considering renovating your bathroom, or maybe you’re due for an upgrade, a bathroom fan should be on your checklist.
But what is a bathroom fan really for?
A bathroom fan is an exhaust-type ventilation system that collects moisture and odors from your bathroom and moves them outside. This ventilation is necessary to prevent excess moisture, mold, and rot in your home.
Unfortunately, for many older homes, bathroom fans are the only actual means of mechanical ventilation.
If you don’t have an air exchanger in your home, but you do have a bathroom fan, chances are it is the only way to exhaust stale air from your home to the outdoors.
It is essential to realize that bathroom fans function only as an exhaust fan. This means that your bathroom fan is not responsible for bringing fresh air into your home; it is only responsible for bringing ambient air from the bathroom to the outside.
Therefore, using an air exchanger is still essential to get other forms of mechanical ventilation in your home.
(Below) in this article, I will cover the benefit, the different types of bathroom fans, the cost of installation, how to choose the right fan based on CFM and Sones, and some helpful tips.
Table of Contents
- The Key Benefit of a Bathroom Fan
- 5 Different Types of Bathroom Fans
- How to Choose the Right Bathroom Fan: CFM, Sones, & Labels
- How Easy Is It to Install a Bathroom Fan
- How Much Does a Bathroom Fan Cost
- Should You Leave the Bathroom Fan On: SOLVED
- Can Bathroom Fans Affect the Environment
The Key Benefit of a Bathroom Fan
The key benefit of a bathroom fan is primarily for your home’s health, as it is directly responsible for managing humidity levels and eliminating odors from your bathroom.
It is also good to know that high humidity levels create ideal conditions for pests such as cockroaches and dust mites.
However, the biggest drawback of bathroom fans is that they are usually a retrofit option, which means you will have to create a new hole in the side of your home to use it.
And that plays against the airtightness of your home, and you’ll want to consult an experienced professional to do the job.
Most bathroom fans serve the same function of getting rid of excessive odors, humidity levels, and even mold spores that build up in a damp bathroom environment.
However, fans differ depending on where they are mounted, how they expel moisture and air inside bathrooms, and any extra features they may have.
5 Different Types of Bathroom Fans
1. Ceiling Mounted
Ceiling-mounted bathroom fans are the most typical type of installation.
They are recessed inside a ceiling cavity and exit through the ducts to the outside of the house.
2. Wall Mounted
Wall-mounted bathroom fans are relatively common and are attached directly to an exterior wall.
Some people complain that they can be more prone to drafts and don’t do a good job capturing moist rising air.
3. Building Exterior Mounted
Building exterior-mounted bathroom fans are fans that, as the name implies, are mounted on the exterior of a building and are most common in commercial applications.
In-line bathroom fans are built-in and refer to whole-house systems such as HRVs and ERVs that replenish the bathroom air with fresh air to other rooms in the home.
5. Smart & Lighting Features
Bathroom fans with light fixtures are versions that have built-in LED lighting, and some now even have Bluetooth speakers built-in if you want to be a tech geek.
Some of the most recognized brands in this category are Panasonic, Delta, Nutone, and Broan.
How to Choose the Right Bathroom Fan: CFM, Sones, & Labels
When choosing a bathroom fan, the first thing to do is find the ideal one that fits the space.
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And the ideal way to find out is to look at two clear indicators: CFMs and Sones.
Bathroom Fan CFM
Bathroom fans are rated by their CFM rating, which is their cubic feet per minute indicator, also known as the amount of air they can move in less than a minute.
Generally, a more powerful fan will give better results. Still, you also don’t want to overpower your bathroom with a huge fan or pay more for an enormous one you might not need.
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And generally, the higher the CFM, the louder the fan will be.
Now the quick and easy way to calculate the size of fan you need is with this simple math equation.
And all you need are the approximate measurements of your bathroom.
For example, let’s say a small bathroom 9×5 ft wide and 8 ft tall ceiling; you multiply those three numbers by 0.13. This will give you the minimum CFM rating required for that bathroom.
You must also factor in the CFM loss for the amount of ductwork installed.
Typically, you can calculate a 7% CFM loss for every 25 feet of flex duct and 3% for every 90-degree turn.
Bathroom Fan Sones
This is essentially the second indicator that tells you how loud your fan will be.
And fans are usually below three Sones.
This is tricky because while a lower Sones number means a quieter fan, there are fans out there that are very quiet.
Sometimes having a noisy fan, especially in bathrooms that guests often use, is doing a service to you and your visitors, if you know what I mean.
Labels to Look for on a Bathroom Fan
Energy Star label: So once you feel good about the CFM rating and Sone level, look for the Energy Star label.
The efficiency requirements for bathroom fans are still pretty low to meet Energy Star standards.
HVI label: The other is to look for an HVI label for Home Ventilation Institute.
This institute certifies home ventilation products, and for bathroom fans, it affirms that the manufacturer’s details are what they are, especially regarding CFMs, Sones, Wattage, and illumination.
How Easy Is It to Install a Bathroom Fan
Now, when it comes to installing your bathroom fan, it can get pretty complicated pretty quickly.
An ease fan installation will depend mainly on the location of your bathroom within the house, whether there is an existing fan and ductwork, and whether or not there is wiring already in place or accessible.
Now a quick note on older homes and vent fans to the attic, make sure your vent goes to the outside.
I see a trend for older homes to have their exhaust stop in the attic and not reach outside, which can cause many problems in your attic space.
How Much Does a Bathroom Fan Cost
There is a broad range of prices to choose from, but usually, for a small and efficient bathroom fan, you can get it for around $100 to $150.
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Now keep in mind that is just the price of the fan itself.
You’ll need a licensed electrician to wire it up, install it and vent it to the outside.
And you may also have to do some patching on the wall if you’re replacing an old unit, which again adds to the price.
In the end, most of the price is actually in the installation and accounting for replacement parts such as exhaust ducts, wiring, and switch installations, which brings the cost of a bathroom fan installation closer to the $300 to $500 range for a fully operational fan.
You can also do some things to save on the cost of running that fan in the future.
Try to choose a model that, at a minimum, is Energy Star rated.
And going one step further, look for a fan with a high CFM per watt rating.
Some models go as high as 19 CFM per watt, so try to find one with a rating of at least 10 CFM per watt.
This means that the most efficient models use as much energy as a typical LED bulb.
Should You Leave the Bathroom Fan On: SOLVED
Never leave a bathroom fan on for too long because they tend to overheat and accumulate lint and dust over time, which could pose a fire hazard.
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But installing a timer switch is a great way to control your bathroom fan easily.
Here’s the lowdown,
All bathrooms by building code are required to have a ventilation fan.
The only exception is if the bathroom has a window to the outside that you can open.
But even if the bathroom has a window, I suggest businesses and homeowners have a bathroom fan installed.
So a bathroom fan, of course, as I mentioned above, is to ventilate the humidity in bathrooms, which is an essential function.
And they’re usually connected to a normal two-pole on/off switch.
On the low end, the bathroom fans operate at 50 cubic feet per minute, pulling about 50 cubic feet of air every minute.
And that’s assuming you have a very short duct that it’s connected to.
But the idea is that these fans only pull about 50 CFM, and that’s on the low end, and they can go up to 100 to 120 CFM on the really powerful ones.
But again, that’s assuming it’s only pushing air a very short distance.
We’re all familiar with those bathroom fans that make a lot of noise and sound like they’re doing something, but we never really feel the air moving.
We know these fans barely draw any air, so what do we do?
We turn them on, and they run while we’re in the bathroom, and then basically, they’re not accomplishing anything because when we come out of the bathroom, we turn off the fan.
So the fan hasn’t pulled all the moisture out correctly because we haven’t given it the time it needs to do its job.
The solution is to install a timer switch on the bathroom fan. I believe every business and homeowner should have one in every bathroom with a fan.
And after installing the timer switch, you can set the timer for a certain number of minutes when you leave the bathroom. The fan will run for those minutes and automatically shut off.
And you don’t have to stand around holding the switch, turning it on, or letting it run for 20 minutes and then forget about it and have the fan running all day, which is not a good thing.
How Long Should You Run the Fan in the Bathroom
I’ve done some math to help you understand how long you should leave the bathroom fan running.
For example, let’s say for an 8×15 ft bathroom, that would put it at 120 square feet of floor space, and if the bathroom has an 8 ft tall ceiling, you’re going to have a total of 960 cubic feet of air space in that bathroom. And if your fan is pulling at 50 cubic feet per minute, pulling all the air out that 960 cubic feet of bathroom air space will take 20 minutes.
So you’re not going to stand there for 20 minutes, of course, while the fan puts the air out, and then you come back half an hour later and turn it off.
It would be ideal if you had a way to make that fan turn off automatically.
Another example, let’s say you have a more powerful fan that can pull about 100 CFM with the same 960 cubic feet of bathroom air; you are still looking at 10 minutes for the fan to pull that volume of air out.
Now, if you have a 4×8 ft half-bathroom with an 8 ft tall ceiling, you will have about 250 cubic feet of air space in that bathroom, and a 50 CFM fan will still take about 5 minutes for the fan to pull the air out.
So putting the bathroom fan on a timer is a better way to go.
There are different timer switches, including the push button where you can push in a 5, 10, 15, or half-hour, which is excellent.
The other type of timer has a mechanical dial where you have to turn it manually clockwise, also known as an analog timer.
And the other type of timer is a smart switch that you can program to run at a specific time desired.
Can Bathroom Fans Affect the Environment
Generally, products in this category, regardless of the manufacturer, tend to be very similar regarding the materials used and their origin.
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Most of these fans are made from molded plastics and lightweight steel. Therefore, it is not overly innovative and, for the most part, takes a bit of energy and resources to create.
Most of these products are made overseas, but if you can find a version made in the USA, it’s a great way to reduce the footprint.
Also, choosing a version with high CFMs per watt, at least ten or more, is another excellent way to reduce the impact of your daily use, which will also translate into savings for you.