Bathroom Ventilation: What Happens When You Do Not Have Outside Access?


Bathroom Ventilation: What happens when you do not have outside access?

Sometimes it can be difficult, if not impossible, to vent a bathroom to the exterior due to the building’s design. What happens next? Well, there are specific tips that you could use to improve your bathroom’s ventilation.(Bathroom Ventilation: What happens when you do not have outside access?)

We know that bathroom ventilation isn’t a problem for most people. In many cases, a fan/light is installed in the ceiling and then vented through the sidewall, soffit, or roof. You only need to flip a switch, and the excess moisture or odors is vented out.

However, many individuals are living in houses that make it impossible to install fan vents to the outside. Solving this problem can be a colossal nightmare considering that proper ventilation is a must-have.

In this article, we will discuss how to vent a bathroom with no outside access. However, the project will require smart product selection, construction creativity, and an experienced HVAC constructor.

Building code and bathroom ventilation

We can’t jump right into solving a bathroom’s ventilation before looking at building code requirements. If we go back in history, people already understood the houses needed ventilation even before indoor plumbing.

Soon bathrooms went indoors, and proper ventilation was required to get rid of odors and excess moisture. With improved technology, there is more moisture build-up in the bathrooms. When taking a hot shower, all the mirrors get fogged and condensation forms on the walls and windows.

The current building code in most municipalities states that bathrooms need to be vented using an operable window or an exhaust fan. However, understand that the window option is considered as a minimum standard. This means that it cannot be viewed as a reliable or effective ventilation option.

Signs that you may have bathroom ventilation problems

Modern houses are more highly insulated and airtight when compared to those constructed in the past. The right insulation and airtight construction ensure that you get more interior comfort and low carbon emission levels. Other added advantages include saving on both electricity and fuel.

However, the tight construction will create a lot of indoor air pollution, which calls for proper ventilation. You will start noticing molds due to excess moisture if you don’t have adequate ventilation. Health experts will tell you that mold is a severe issue that causes many allergic reactions and respiratory ailments. Your building will also get damaged over time since they affect the gypsum and wood boards.

If you notice stains on your ceiling or wall, then you lack proper ventilation. You, therefore, have too much moisture in the house due to the bathroom air. Yes, sometimes, you might not see the mold, but the unpleasant smell should be a definite sign.

Now, there are so many reasons why you might need to install proper ventilation in your bathroom. However, preventing mold is the number one reason for almost all individuals.

Getting the right bath fans

Whether you get to install your bathroom fan in a straightforward or complicated manner, you need to understand what to look for during purchase. Below are some necessary details that will ensure you get the right bath fan that suits your needs.

1. Size

There are different sizes of bath fans depending on the volume of air that they can move. You will notice that they are measured in cfm (cubic feet per minute). The rule is that every square foot needs one cfm to get you proper ventilation. However, if your bathroom is used frequently, then you will need to get a fan vent with a higher rating.

2. Special features

You have to consider the unique features that are included in the bath fan. For example, a fan that has integrated lighting ensures that you won’t need to install separate light fixtures in your bathroom. Variable speed control features will also get you more exhaust power, especially when you have high humidity levels.

How to vent a bathroom with no outside access

In this section, we will discuss the different options that you have when you need to vent your bathroom with no outside access. However, understand that you will need a professional HVAC contractor for these unconventional installations.

A recirculating fan for a half bath: Understand that a recirculating fan doesn’t exhaust the air to the outside. Instead, it works by passing the air in your bathroom through a filter, thus ensuring that all the odor is removed. It is, therefore, a perfect option for half baths because there are no installed showers, which means that the moisture level is deficient.

An inline fan to reduce noise: Powerful fans tend to produce more noise since they push air through long duct runs with several elbows. You can use an inline fan to reduce the noise levels around your living space. Simply install the inline fan anywhere along the duct run for better results.

Vent beneath the floor: if your fresh bathroom is situated away from your exterior wall, you cannot vent through the roof. This is a common issue, primarily when your bathroom is located in a renovated building or under a stairway. You need to ask your HVAC contractor whether it is possible to extend a bath fan through the floor. In these situations, the plumbing vent will run between the floor joints and out through the exterior wall.

Install commercial ductwork: This is usually the best option when smaller apartments are constructed in a larger building with high ceilings. The bathroom ductwork gets feed into one long run in a commercial setting. Think about it the way retail stores and restaurants fix their bathrooms.

Hide ductwork using a soffit: a soffit built along your wall will help hide the duct run. It is the right solution that gets you maximum functionality.


Understand that you will need an experienced HVAC contractor to install the above options successfully. The contractor will help you decide which method will be most effective in your situations. You can equally look through different reviews to understand how the various techniques work.

About the Author Mike Chua

Vircet is your one-stop modern products website that offers you detailed reviews based on efficiency, capacity, design, and performance. We help you make better decisions.

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