How To Choose Bathroom Exhaust Fan

As we mentioned earlier, choosing a correct bathroom exhaust fan might be tricky. But once it is fit, you do not need to worry about it for over many years to come for. Today, in this guide, we will be talking about the various important factors one needs to consider while picking an exhaust fan.

1. Types of Exhaust fans

Exhaust fans are primarily of only two types.

a. Kitchen Exhaust Fans: These fans are primarily used in kitchens to drive out smoke and other minute particles of air. Not so ideal to drive out damp airs.

b. Bathroom exhaust fans: As the name suggests, these exhaust fans are specifically designed to push out damp air and moisture from insides of bathroom to the outside.

Make sure that you are covering all of the following important factors before you make a choice of buying a bathroom exhaust fan.

2. Size of the fan.

This is without saying the first and the foremost important factor one needs to look for before picking a fan.

You cannot randomly walk into a store and expect a single size of fan to fit the bathrooms window. Most people think that a big window with a small fan will help push more air outside but this will just led to random and unfiltered air to enter your bathroom and increase the overall moisture levels of the room.

Larger windows need bigger fans whereas smaller windows need smaller fans and all of these measurements are taken in the form of “cubic feet per metre” or CFM. The CFM value decides how much ventilated fan you need for your bathroom.

For this, first you need to calculate the square size of your bathroom by foot. This is nothing but the product of the width of the wall to the height of the room. For instance, if the bathroom is 5 feet wide and 7 feet tall, then the room is 35 square foot (which is not that big).

It is a good idea to get a fan that is slightly bigger than the size of the exhaust fan wall. A standard size is about 60 CFM while the minimum available size begins with 50 CFM.

If your bathroom has a jetted tub or any other dual room or shower cabins or anythings as such, then it is suggested that you get more than one fan. A single fan may not be that helpful.

The following chart will guide you in picking the right size fan for your bathroom wall.

Size of the bathroomRequired Ventilation in order of CFM
< 50 sq. ft50 CFM
50-100 sq. feet1 CFM per square ft
>100 sq. ftDifferent fixture have different sizing measurements
1. For Toilet-50 CFM
2. For Shower-50 CFM
3. For Bathtub-50 CFM

3. Noise factor:

This may seem like a laughable factor but cheap and ill quality bathroom exhaust fans are often very noisy and messy. But until you have installed a fan in your bathroom, you never can experience if the noise emitted by the fan is bearable or just too much to bear.

In order to get an idea of how noisy these fans can be, there is a unit of measurement called Sones.

The sones value of an individual fan gives you an idea whether the fan is noisy or has bearable sound emission. It is not just for fans but also gives you an idea of how electrical or other items work.

For instance, when you switch on and use a Television, the typical sound is about 4 sones, a fridge has a sound of 1 sone and the sound generated by rustling leaves on a tree are just about 0.5 sones. An ideal bathroom fan should have a sone value of 1 or 2. Higher means noisy. There are even models with sone levels as low as 0.3 too. It is all about how better of a research you do before picking the right product.

4. Efficiency

The next important factor one has to look for is the efficiency of the fan. While these fans may seem like small pieces of equipment, you need to consider the fact that, if picked wrong, they may end up consuming a lot of power.

Silent fans are silent in operation and do not consume a lot of power too. But this doesn’t mean that loud fans consume a lot of power. The efficiency of the fan is dependent on its star rating.

Before you buy a product off a shelf, be sure to check its star rating as this will give you an insight of how energy efficient the product is.

Big brands often make sure that the fans produced by them are energy efficient. Fans approved by Energy Star are known to have over 75% energy efficiency which is a splendid percentage.

5. Blade Material

This may be an important factor for kitchen exhaust fans, but it has not that big of an impact when it comes to bathroom exhaust fans.

In the case of kitchen exhaust fans, the build material may lead to backdrafting but when it comes to bathrooms, formation of cloth lint or any other combustibles on the surface of the fan blades is not possible.

Even though, the blade material can be considered to compare and contrast the overall build quality of the fan.

Metal blades are durable where as plastic blades are not that durable but are a very economic and pocket friendly option.

6. Pricing

Not a very important factor to look out for but is important if you are on a shoestring budget but want a quality product.

Bathroom exhaust fans in general are not a costly affair. They typically are between the price range of about 800 to 2000. Higher price promises better quality and vice versa.

7. Warranty:

Typically, an exhaust fan promises about 1 or 2 years of manufacturer’s warranty. This means that whenever there is an internal malfunction or if the product is broken upon delivery, one can claim the warranty.

While many a companies have dedicated cards for warranty, often, your bill acts as the warranty proof. If the fan breaks up due to external pressure or due to falling down or due to usage by negligence, no claims of warranty are entertained by the fan company nor the seller.

How to install a bathroom exhaust fan

Installation of a bathroom exhaust fan is similar to that of any exhaust fan. Follow the given steps to successfully install a bathroom exhaust fan.

  • First find and fix the place where you want to install the exhaust fan.
  • Most of all modern and even retro bathrooms come with a place above the window where you can fix and install an exhaust fan.
  • Now open the screws and install the fan as per the instructions give on  the fan.
  • Different fans have different screw settings and fittings.
  • After the fan is fixed, make sure you are adding insulation and covering up the leftover gaps between the window and the fan frame.
  • When you are done with fixing the fan on the window, now you have to set up the wiring of the fan.
  • Add the wiring of the fan to the circuit board of the bathroom
  • If the fan comes with an outer cover case, fix it, else, there are outer case covers for exhaust fans that are available online too. Buy one and fix it for extra precautionary measure.

While that was the procedure for a normal exhaust fan, if you are installing a duct based bathroom exhaust fan, the installation procedure is a bit different.

  • Find a certifiable and close to the outside part of the roof in the bathroom.
  • Cut a hole and look for an outside way for the duct to go.
  • Never prepare a duct that goes into the attic as all of the moist and humid air will end up circulated into the very same room.
  • Place the duct and direct the ending of the duct to the outside of the room.
  • Fix the fan to the ceiling of the bathroom roof as mentioned in the steps above.
  • Set up the wiring and you are good to go.

Frequently Asked Questions (FAQs)

1. What is CFM?

Cfm means cubic feet per minute, it is defined as the amount of air volume moved by the fan.  Opt for a fan with minimum cfm of 50. Most of the fans come with cfm of 50-100. A fan with cfm of 50 is suitable for small sized rooms.

2. What is sone and how it is measured?

Sone is the measurement of noise emitted by a fan, it is better to go for the fans with sones of 2 or below. Higher sones indicate more noise.

3. What is the sweeping size of a fan?

It is the total diameter of fan blade, however large diameter cannot give you better air delivery.

4. What are timer features in the fans?

Timers of the fans are used to shut off the fans at a fixed time. Not important but always comes in handy.
While typical exhaust fans may not have an exhaust fans, if you are in the need of an exhaust fan that works in a crowded place such as for your restaurant or your workplace, consider this as an option.

5. Which type of duct is best, flexible or rigid?

It is advisable to use rigid duct whenever possible. Its resistance to air flow is less and allows the fan to operate with better efficiency.

6. How long should you run your bathroom exhaust fan?

After using the bathroom for a shower or for any other usage, the recommended time for the running of the exhaust fan is about 20 minutes to clear out, expel and eradicate all odours formed in it.

7. Can I leave the bathroom fan running all night?

As mentioned earlier, 20 minutes is the maximum and the required amount of time for an exhaust fan. Leaving the fan powered on all night would lead the ball bearings present in the fan to be at fault and this would in turn damage the fan as a whole.
Also, there is a high and sure probability of your electricity bill spiking up to a big number.

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