How Should You Ventilate Your Shipping Container Home?

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Updated On: December 22, 2022

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Ventilating your container home goes almost hand-in-hand with adequate insulation. Without proper ventilation, your shipping container may experience a variety of liveability issues. including stale air, rust, and condensation.

Ventilation is even more important when we consider tiny shipping container homes which are less than 600 square feet because any ventilation issue is enhanced due to the small space.

Shipping containers are designed to be inherently airtight. This is due to them being used to ship goods in all kinds of weather across the ocean. When goods are inside containers they must not be exposed to corrosive saltwater.

When we use shipping containers as habitable buildings, this can cause issues. Buildings require ventilation. Today we are going to address exactly how you can ventilate your shipping container home.

Problems Caused By a Lack of Ventilation

Poor ventilation can go be described in two ways. You can have a home that lacks ventilation and doesn’t allow the movement of external air to enter your shipping container. You can have a home that provides so much ventilation that it is either impossible or very expensive, to maintain a consistent temperature inside the container.

Having poor ventilation within your container can cause harm to both your home and the people living inside. One of the biggest problems caused by poor ventilation is mold.

Stale Air

Poor ventilation has been linked with numerous human diseases such as pneumonia, dry eyes, and nausea. In addition, it has been linked with respiratory diseases, the most common of which is asthma.

Poor ventilation can also lead to dampness which creates musty odors. You’ve probably smelled this before if you’ve walked into an old room that hasn’t had any fresh air for a while. Because the air has nowhere to go, any scent within your home will linger and cause a buildup of generally unwanted scents.

Condensation

Improper ventilation is also a strong contributing factor in the development of condensation in a shipping container. Condensation is water vapor that has condensed, or turned into visible droplets, on a surface.

Condensation-Windows

Rust

Poor ventilation can also lead to a buildup of condensation which can cause your steel containers to rust. This rust can also affect any metal pipework (such as your plumbing). Repairs to rusting containers can be a time-consuming and costly job.

Mold

Mold is a fungus that when left untreated can be very expensive to remove and when its fumes are inhaled by a human can cause harm.

Types of Ventilation

So now that we know what can happen if your containers don’t have sufficient ventilation, let’s address how to ventilate your containers. There are two overarching methodologies when it comes to ventilation. The first method is passive ventilation and the second method is mechanical ventilation.

Passive Ventilation

Passive ventilation gives you the ability to ventilate your home without having to spend lots of money. Essentially, it utilizes natural processes like convection and wind to ventilate your home.

Cross Ventilation

The cheapest and most common way to provide your containers with passive ventilation is to install vents or use open windows and doors in your container. These vents allow the wind to blow air into one side of your containers and out another side.

cross ventilation
Adjacent wall and opposite wall cross ventilation (Source)

The name cross ventilation comes from the fact that air blows through or across the room when the vents are properly placed. Essentially, positive pressure accumulates in the room where the wind blows air into one ventilation opening, and the second opening allows that pressure to equalize back to atmospheric pressure by allowing equal amounts of air to escape.

While you technically can have ventilation provided by a single vent, it’s usually not very effective. Air tries to both enter and exit through the same opening ends up not mixing very well, and much of the room’s air never leaves. Additionally, you can in some cases end up with the wind-buffeting noise issues that are common in many cars. Instead, we almost always recommend cross ventilation using two or more vent openings on adjacent or opposite walls.

Stack Ventilation

Stack ventilation has similarities to cross ventilation, but it occurs in a more vertical manner and is less dependent on the wind. Instead, heat (typically from the sun) causes air to rise through a home. When there are both low and high openings in a home along with materials that can experience sun warming, air will enter at the bottom and exit at the top.

It’s a common technique for unoccupied attics in southern climates, where whirlybirds are commonly employed to keep air circulating during the hot summer months. But they can also be used in living spaces, and even accentuated using a passive cooling technique known as the chimney effect.

One great example of stack ventilation is the Containers of Hope house. This shipping container home in San Jose, Costa Rica uses windows placed just beneath the roof to allow air to blow through the containers. These strategically placed windows keep the container cool on hot summer days and it also helps to reduce the humidity of the containers.

Mechanical Ventilation

In certain climates, such as very humid places like southern Brazil, passive ventilation is insufficient and mechanical ventilation is required.

In fact, in many countries like the US, Australia, New Zealand, and the United Kingdom it is a building regulation standard to fit mechanical ventilation in kitchens and bathrooms. Depending on your country the minimum amount of extraction required is 15 liters per second in each room.

People normally attach an extractor fan (which is a type of exhaust-only mechanical ventilation) to meet this building regulation.

This fan allows the humidity to be extracted out of your home before it settles on a surface and turns into moisture and dampness. The fan should be attached as high as possible on the wall which is furthest away from the main source of air placement (either your door or window).

Supply Only Ventilation

The opposite of exhaust-only mechanical ventilation is supply-only mechanical ventilation. This is where, instead of the fan pushing stale air out of your home, the fan sucks fresh air into the home. Supply-only ventilation is very useful when your home has passive ventilation systems in place and you just need to increase this passive ventilation on hot days.

Ventilation-Fan

Balanced Ventilation

Your final, but most expensive option is to use a balanced ventilation system. This involves having fans to both push stale air out and suck fresh air in. The air can then be sent throughout your container using ducts.

In moisture-prone areas such as bathrooms and kitchens, air can be extracted, and fresh air can be blown into other areas of your home such as the lounge and bedrooms.

Using a balanced ventilation system does allow you to very easily manage the moisture and humidity levels in your home.

Dehumidification

Although not a mechanical ventilation device, a dehumidifier can help stop many of the problems caused by bad ventilation. A dehumidifier reduces the level of humidity in the air and thus can reduce the water content and stop condensation from corroding your containers!

They can be purchased as small stand-alone appliances which can be moved from room to room. You can also buy entire home solutions which have ducts fed throughout the container.

Foundation Ventilation

One issue which we haven’t discussed so far is the importance of ensuring your foundation is ventilated. This is known as crawl space ventilation.

Not all foundations can be ventilated. For instance, if you have a slab foundation you won’t physically be able to ventilate it. However, if you have a concrete pier foundation or any other type of raised foundation, then you need to ensure you have sufficient airflow underneath your containers.

Failure to ventilate your foundation can bring back that dreaded condensation which can cause your foundation some serious problems such as mold and rot. In addition, if your shipping container floor hasn’t been insulated, you can experience even more problems such as moisture rising up from underneath the containers into your flooring.

The most common way to stop moisture and allow ventilation underneath your foundation is to use vents.

Shipping Container Foundation

Many areas stipulate through their building code that you must use vents to provide your foundation with airflow. These vents typically have a wire mesh screen which keeps pests and insects out of your crawl space.

Vented crawl spaces work well in cold climates. In humid climates, using a vented crawl space can actually do more damage than good because the external air is more humid than the air already in the crawl space.

In humid climates, it would be better to seal off the airflow to your crawl space completely and use a dehumidifier.

Let us know how you chose to ventilate your shipping container home in the comments below!

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10 Responses

  1. Thank you for all these solid and important pointers.

    My query is about foundation ventilation. Say if I decided to place my container home on a concrete slab, and raise it about 1.25ft from the concrete surface. Would that be enough to keep the bottom of the container ventilated with enough air flowing beneath it?

    1. Sarah, yes, that would be fine. Over the past few years, building scientists have started to question whether ventilated crawlspaces are even a good idea. Depending on the climate of where you live, ventilated air that is introduced to the crawl space may actually have more moisture than the air it replaces. We’ll work on updating this article a bit to reflect the latest best practices, but here is a good resource to consult on this topic: https://www.advancedenergy.org/crawlspaces/

  2. First of all, I wanted to thank you for the effort of putting together all this precious info here!
    Next to the permits here in burocratic Belgium my biggest concern is indeed the isolation/condensation/ventilation issue. The lot I am looking at has a lot of trees giving shade and overall temperatures don’t rise too high in the summer. So I will have to focus mainly on keeping it warm in the winter. I would like to insulate from the inside, to keep the industrial look of the container.
    The ccSPF method will probably be my weapon of choice, but I am worried about ventilation, since you seal everything this way. Would it be an idea to have a little gap (1-2″) between the container wall and the isolation and then drill little holes in the container so air can flow between the foam and the outer wall?
    The living area is easier I guess, using vents and opening windows from time to time.
    Correct me if I’m wrong, I’m still learning!
    Thanks

    1. Thanks Phillipp. First, if you haven’t read this article, you should check it out: https://www.discovercontainers.com/container-condensation-prevention/

      Adding this air gap isn’t really recommended, as it only further reduces your room sizes. Since ccSPF is a vapor retarder, moisture shouldn’t migrate through the insulation and be able to contact the container’s corrugated skin anyway. You do need to consider ventilation, but how much is needed depends on a lot of specifics with your project. Things like a bathroom exhaust vent and range hood can take care of most moisture, but something like an ERV (https://en.wikipedia.org/wiki/Energy_recovery_ventilation) might be necessary if you have a lot of moisture sources, rarely open windows doors, etc.

  3. Hey guys, I’m looking to build a container workshop. I’d like to avoid insulating the walls but I’m not sure if I can avoid the condensation issues with mechanical ventilation on its own… Any advice? I’m in Canada and would be heating the unit in the cold months to keep pipes from freezing.

    Thanks

    1. A cold environment is the toughest for condensation. Any sources of moisture, like your breath, are going to increase the humidity of the interior air. When that warm, moist air hits the cold container walls, it will condense. If you have to keep it warm, you should consider using a dehumidifier. However, warm, dry air may not be so nice to breathe. Another option is using electrical strip heaters for your pipes while keeping the room temperature approximately equal to the outdoor temperature. But, then you might be freezing when you’re trying to work! If you haven’t already, check out our article on condensation that goes into this more: https://www.discovercontainers.com/container-condensation-prevention/

  4. Do you have a topic of installing solar chimney on shipping container house?and if i want to build roof on the container, is it open gable roof or shed roof better in ventilation performance?

    1. No, we haven’t covered this topic in depth on the site yet. Perhaps a future article! For ventilation performance, there shouldn’t be a discernable difference between shed and gable roofs. Assuming your build is only one container wide, the shed roof will be easier to build, so that can be a controlling factor.

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