How to ventilate a room without windows

Don't let a windowless room become an obstacle to airflow and ventilation
By
Updated on May 16, 2024
Written by
Jeff Somers
Jeff has been writing for HouseFresh since 2023. He lives in Hoboken, NJ with his wife and their cats, and has published nine novels and more than fifty short stories. In addition to writing for HouseFresh, Jeff also covers topics connected to home ownership for Lifehacker,
TL;DR

A room without windows can significantly challenge ventilation and indoor air quality (IAQ). Even worse, stale, stagnant air can allow dangerous gases, allergens and pollutants to build up in the room, making it unpleasant and difficult.

Luckily, you can improve the ventilation in a windowless room in several ways, many of which are easy and inexpensive. Passive ventilation and cheap fans can refresh stale air, and adding an air purifier to remove particulates makes air fresher and more pleasant to breathe.

When you buy a house, you’re also purchasing an unexpected education in the systems that support it. Chief among these systems is the home’s ventilation and airflow, which most of us don’t think about until we deal with the challenge of ventilating a room without windows. 

Whether it’s a finished basement that smells … unfinished or a bonus space converted into an unofficial bedroom, a windowless room can be challenging to ventilate correctly, especially in modern homes that are much more airtight than older ones.

And ventilation is essential for both your comfort and your health. Luckily, you have many options for ventilating a room without windows, ranging from no-cost, no-work alternatives to more ambitious projects.

Every space is different. Depending on the room’s location in the house and access to exterior walls, you can pursue a few different strategies for improving its airflow.

1. Improve airflow inside

The first step in improving ventilation is to improve the airflow within the space:

  • Open doors – The easiest thing to do is to open up (or remove) the door to the space, allowing the air from the rest of the house to flow into it and the stale air to flow out.
     
  • Declutter – If the room is packed full of stuff, air won’t be able to move. Removing extra furniture and storing everything out of the way will help improve ventilation.
     
  • Add fans – A doorway fan, ceiling fan, or even an inexpensive pedestal fan can create a healthier airflow.

2. Introduce fresh air

Improving airflow is critical, but a more comprehensive solution will involve bringing fresh air into the space. If the room has an exterior wall, you should consider finding a way to get outside air into the room:

  • Extractor fan – An in-wall air conditioner with a fan setting or an exhaust fan (sometimes called an extractor fan) can help bring fresher air into the room. 
  • Transfer fan – Adding this to an interior wall can help bring air in from the rest of the house or a room with an exterior wall with a fan or AC unit installed.

If an air conditioner or exhaust fan is out of the question, consider more passive ventilating materials:

  • Air bricks: These bricks contain ventilation holes that allow air to pass through them. Installing one in an exterior wall will allow outside air to circulate.
  • Passive vents: Resembling a heating or cooling vent, these are air inlets with louvers that rely on natural air movement and pressure to ventilate a space. 
  • Mechanical ventilation system: Installing a mechanical system is the most effective way to ventilate a windowless room. A Mechanical Ventilation with Heat Recovery (MVHR) or Single Room Heat Recovery (SRHR) system pulls stale, hot air from the room, extracts the heat, and then introduces fresh air back into the space. However, these systems can be expensive and complex to install, especially when retrofitted.

The best solution for ventilating a windowless room is to find ways to bring fresh air into the space—but if that’s not possible, or if passive ventilation techniques aren’t moving enough air, you can improve the situation with an air purifier. 

Even if your solution adequately ventilates a windowless room, an air purifier can improve the air quality in the room even more.

That’s because passive ventilation systems and interior-mounted fans aren’t removing pollutants from the air—they’re just moving them around. Even if you’re pulling air from the rest of the house, you’re likely simply shifting a set of particulates from one space to another because they have nowhere to go. 

It’s also worth mentioning that when bringing fresh air into a space, unless your ventilation system includes a filtering component, you’re probably bringing new pollutants into the room as well, exacerbating the situation.

An appropriately sized air purifier equipped with a high-efficiency particulate air (HEPA) filter combined with a passive ventilation system or some fans will capture those allergens and other particles and help ensure the mood you’re moving into your windowless room is clean and healthy.

Not sure which air purifier to get? We have ranked the best air purifiers based on hours of testing in our home lab. If you’re still unsure after reading that article, email Danny at danny@housefresh.com; he can help.

Why is ventilation so important?

One of the primary motivations for improving room ventilation is to eliminate damp or bad smells. Stale air has a scent caused by carbon dioxide (CO2) buildup and mold and mildew growth. 

And air that isn’t moving can amplify other smells in the space, making it unpleasant to be in the room, which reduces its usefulness.

But a room lacking ventilation and fresh air isn’t just uncomfortable—it’s unhealthy. Contaminants like germs and dust can’t be filtered out without proper ventilation, which can help spread diseases and exacerbate conditions like asthma. 

 A windowless room can lead to a buildup of harmful gases like CO2 or radon, a carcinogen. And poor indoor air quality can result in a long list of health issues, including

  • Fatigue
  • Fever
  • Nausea and digestive problems
  • Loss of concentration
  • Chronic headaches
  • Airway irritation
  • Respiratory disease
  • Heart disease
  • Cancer
  • Liver and kidney damage

Just as important as your health is the health of the house itself. Poor ventilation can make a room more humid, leading to uncontrolled mold growth. Indoor mold can have a substantial and negative impact on your health, causing breathing difficulty, skin rashes and other allergic reactions. 

Airflow is crucial in reducing humidity, as it allows the humid air to be vented outside and encourages drier air into the space.

Final thoughts 

A windowless room can be an obstacle to getting the most enjoyment and use out of your home if it’s stuffy and unpleasant—not to mention the potentially negative impact on your health.

But you have a range of options for improving the situation, some of which cost very little money and time, so there’s no reason to put up with a lack of ventilation. 

A few dollars, some creativity and an understanding of the vital importance of proper airflow are all you need to make a windowless room not just usable but enjoyable.

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About the author

Jeff Somers

Jeff has been writing for HouseFresh since 2023. He lives in Hoboken, NJ with his wife and their cats, and has published nine novels and more than fifty short stories. In addition to writing for HouseFresh, Jeff also covers topics connected to home ownership for Lifehacker,

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