Flexible or Rigid Duct For Bathroom Fan: Which is Better?

Flexible or Rigid Duct For Bathroom Fan: Which is Better?

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Choosing between flexible or rigid duct for bathroom fan can be very confusing because there are many things to consider to avoid making a mistake that will cost you fortunes later.

The question now is, what is the best duct for a bathroom exhaust fan? What are the rules guiding the installation of a bathroom fan?

Before installing any duct in your house, it is essential to check the code regulating such installation in your area. It would be best if you were sure that your municipal permits such duct’s installation to avoid stories that touch. 

Flexible or rigid duct are both good for bathroom exhaust fan, but rigid duct is the best as it is more durable and less resistive than flexible duct, which is seven times more resistive than the rigid duct. 

However, both flexible and rigid ducts have things that made it better or worse than the other, yet, they are still suitable for bathrooms. You have to verify the one approved by your municipal before installing as some places do not endorse the use of either flexible or rigid duct.

The question you need to ask yourself is, do my municipal prohibit the use of flexible or rigid ducts? This is because most places don’t authorize rigid ductwork. If you are in New York, you may want to read the 2014 New York code, which states that:

Air Ducts shall be permitted to be rigid or flexible and shall be constructed of materials that are reinforced and sealed to satisfy the requirements for the use of the air duct system, such as the supply of air system, the return or exhaust air system, and the variable volume/pressure air system.

Class 0 or Class 1 rigid or flexible air ducts tested in accordance with the UL 181 and installed in conformance with the conditions of the listing.

I will advise you to follow the link to read the 2014 New York code HERE. Go down to section 603.6.1 Air Ducts. Carefully read them to be on the safer side. You don’t want to break the rules if you are in New York simply because you did not verify before installing.

However, even if you are in New York or outside New York, the only way to know whether to use flexible or rigid duct is to inquire from a professional licensed roofer in your area.

You don’t have to install the duct by yourself if you’ve never done that before. You can hire a licensed roofer to do that job for you and, by so doing, use that opportunity to ask the type approved to be used in your area to avoid making a mistake that will cost you something in the nearest future.

Flexible Duct for Bathroom Fan

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A flexible duct is one among the ducts that can be used for a bathroom exhaust fan. One noticeable feature of this type of duct is that it is made of rubber, thus, flexible. However, many have argued that flexible duct is not the best while others said it’s better than the other.

Anytime you hear about a flexible duct, know that it is a duct made with rubber and features an inner core filled with spiraled wire, ensuring that the duct is firm. Among other things you can find in any flexible duct is a plastic sheath. The sheath is embedded in the vent.

When using a flexible duct for your bathroom fan, you should try and avoid peaks and troughs because if it’s peak and troughs, it will create extra resistance and dead spots of the airflow.

This is bad because if it continues to do that, it will lead to moisture building up into the puddle of water. If that continues, it will continue to get bigger and bigger all the time.

If the flexible duct continues to accommodate moisture build-up, it will get bigger and reduce the internal duct diameter that the exhaust fan can’t cope with.

If you are asking, can flexible ducts be used in bathroom? The answer is yes; a flexible duct can be used in the bathroom.

Nevertheless, if you wish to use a flexible duct for your bathroom exhaust fan, you have to make sure to pull the duct troughs. It must be supported by every 600mm.

It is best if the flexible duct is insulated correctly to prevent moisture from condensing inside the duct. Doing that will also help avoid water from collecting in low spots, which may destroy the duct if care is not taken.

Advantages of Flexible Ducts

  • Because it is flexible, it is significantly easier to install. It is said to be easier to install than the rigid duct.
  • Flexible duct is less expensive than other metal ducts. This is good for those that are on a budget.
  • Since flexible ducts are made of rubber and flexible, it is possible to fit in some tight spaces where other conventional metal ducts would not have ordinarily fit.
  • Flexible ducts are suitable for internal installation.

Disadvantages of Flexible Duct for Bathroom Fan

  • Flexible ducts can be seven times more resistive than rigid ducts. One thing with this resistance is that bathroom fans can’t cope with such a level of resistance.
  • It is noisier than the rigid duct.
  • There is a possibility of mice and others eating through the material the duct is made. This will lead to punctures and leaks, which will affect the fan’s normal functioning.
  • How long do you think a flexible duct will last? Probably 15 years or more. Be ready to change to a new one even before then.

Importance of Using Flexible Duct for Bathroom Fan

  • To minimize condensation in bathrooms.
  • Flexible ducts can help reduce fan noise.
  • It can be used in several low to high-pressure applications.
  • It is available in different diameters.
  • It is available in different lengths with either plain ends or specific end fittings.

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Rigid Duct for Bathroom Fan

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Rigid duct for bathroom fan has been proven to be the best to use for exhaust fan because it’s smooth inside and doesn’t need supporting in every meter. It is also less resistive.

Rigid ducts need insulating in unheated spaces. You have to make sure to protect it adequately to avoid stories that touch. However, it is also essential to check your location to know if there is any code regulating the use of rigid ducts for bathroom fans.

Advantages of Rigid Duct for Bathroom Fan

  • It is less resistive to airflow.
  • With the Use of rigid ducts, you will not have any issues with moisture build-up.
  • It is certified to last for a longer period. It means that the rigid duct is more durable.
  • It is suitable for any installation; whether you want to install it in a hot or cold air transfer, it’s good to go.
  • It is suitable for any weather and best for external installation.

Disadvantages of Rigid Ducts

  • It can be very expensive to buy and install
  • Because of how lengthy and complicated it is, it should be carefully planned before installation. It is better to call a licensed roofer to do the job for you.
  • It can be somehow heavy. The longer it is, the time it consumes when mounting because it will require a more pronounced installation infrastructure.

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Similarities and Differences Between Flexing Duct and Rigid Duct

  1. Both flexible duct and rigid duct can be insulated to work more efficiently.
  2. While flexible ducts may lead to moisture builds, rigid ducts do not.
  3. Both are easier to maintain.
  4. Both ducts can be used for the bathroom exhaust fan.
  5. While flexible duct is flexible, rigid is not. One is flexible while the other is rigid.
  6. Flexible duct works best in reducing exhaust fan noise when used in bathrooms.
  7. Rigid ducts are less resistive than flexible ducts, which are seven times resistive.
  8. While flexible ducts may last for some time, rigid ducts are certified to last more than the flexible duct.

Between Flexing Duct and Rigid Duct, Which is Better

No one is better than the other. They both have their advantage and disadvantages and little thing that makes them better than the other. Both of them are good and can be used in the bathroom as long as your municipal approves it. However, rigid ducts might be the best because it is more straightforward to maintain than flexible ducts, but you have to follow the rules and use the type approved by your municipal.

Final Verdicts

Flexible duct or rigid duct can both be used for bathroom exhaust fans. However, you have to make sure that your area approves its use. The best way to enquire about that is to call a licensed roofer in your area. He will tell whether you are permitted to use flexible duct or rigid duct. During installation, you must ensure it is adequately insulated to enable the duct to do its works.