Bathroom Ventilation in Canada: Is an Exhaust Fan Mandatory?

Bathroom Ventilation

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In a country where temperatures often dip below freezing, maintaining proper airflow and ventilation in your home is critical. One area that requires special attention is the bathroom. 

The high levels of humidity and moisture generated during daily activities such as showering, bathing, and even using the sink can lead to a multitude of problems if not properly managed.

This is where bathroom exhaust fans come into play. 

But are they required by Canadian building codes? And is it okay to have a bathroom without ventilation? Let’s explore these questions in more detail.

Bathroom Exhaust Fan Code Requirements in Canada

The National Building Code of Canada (NBCC) is the primary document outlining the country’s requirements for building construction and renovation. While the NBCC does not explicitly mandate the installation of bathroom exhaust fans, it does provide guidelines for maintaining appropriate ventilation and air quality within residential buildings. 

These guidelines are more general and apply to all areas of the home, not just the bathroom. According to the NBCC, every residential dwelling should have a mechanical ventilation system in place that is capable of achieving the following objectives:

  • Maintaining acceptable indoor air quality by providing a continuous supply of fresh outdoor air.
  • Controlling humidity levels within the home by exhausting excess moisture generated by occupants, their activities, and equipment. 
  • Preventing the spread of pollutants and contaminants from one space to another within the dwelling.

The NBCC also outlines specific airflow requirements for various rooms and spaces within the home. For bathrooms, the code requires an exhaust airflow rate of at least 50 cubic feet per minute (CFM) when the toilet is in use. This helps to remove moist air from the space and replace it with fresh outdoor air.

In addition to the NBCC, local building codes and bylaws may also have specific requirements related to bathroom exhaust fans. These can vary depending on the municipality, so it’s important to consult with your local building department to determine the exact requirements for your area.

What If You Have a Bathroom without an Exhaust Fan?

While bathroom exhaust fans may not be explicitly required by the NBCC, it’s essential to consider the potential consequences of a bathroom with no fan. Without proper ventilation, excess moisture and humidity can build up in the space, leading to a number of issues, including:

  • Mould and Mildew Growth: High moisture levels provide the perfect environment for mould and mildew to thrive. Not only are these fungi unsightly, but they can also pose health risks, especially for individuals with allergies or respiratory issues.
  • Warping and Damage to Materials: Prolonged exposure to moisture can cause warping and damage to wood, drywall, and other materials in your bathroom. This can lead to expensive repairs and replacements over time.
  • Paint and Wallpaper Peeling: Excess moisture can cause paint and wallpaper to peel or bubble, ruining the aesthetic of your bathroom.
  • Increased Energy Consumption: High humidity levels can make your home feel hotter and more uncomfortable, causing you to rely more heavily on the air conditioning or other cooling methods.
  • Decreased Indoor Air Quality: A lack of proper ventilation can lead to poor indoor air quality, as pollutants, allergens, and other contaminants become trapped in the space.


Although the National Building Code of Canada may not specifically mandate bathroom exhaust fans, they play a vital role in ensuring appropriate ventilation, air quality, and general comfort in your home. A bathroom without ventilation can result in various problems, ranging from health hazards to expensive damages.

To safeguard the health of your family and maintain the structure of your home, it is strongly advised that you fit an exhaust fan in your bathroom.

Do you need a trusted and reliable professional to install an exhaust fan for you? Experience the best commercial and residential plumbing in Oshawa with Hayes Plumbing. Contact us today and let our experienced team handle all your plumbing needs!

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