Do Condos Share Ventilation?

The word condo describes a particular kind of ownership and not a single type of building. Consequently, there isn’t a simple yes or no answer to the question – Do Condos Share Ventilation? To be sure of the type of ventilation in your condo, you would have to ask the condo’s Homeowners Association for the details of the Heating, Ventilation, and Air-Conditioning (HVAC) system in your building, and unit.

However, if you were to ask me “do condos share ventilation?” and I had to give an answer I would say that:

Some smaller condos have separate HVAC systems for each unit. Multi-unit condos usually have a system that forces fresh air down from the roof, into and through the entire building. Separate extractor fans in each unit expel air. However, air can leak between units meaning you do share some recirculated air.

So, what does this mean in practical terms, if you are concerned about air quality and ventilation in your condo?

What Do We Mean By Ventilation?

When we speak about ventilation most of us are thinking about the air coming into, flowing around, and going out of our homes. Technically speaking this is incorrect. To ventilate something is defined as, among other things:

  • To provide (a room, mine, etc.) with fresh air in place of air that has been used or contaminated.
  • To circulate through or to blow on, so as to cool or freshen the air.

However, we are not going to use the dictionary definition of ventilation, nor the engineering or architectural interpretation of the word. Instead, when we talk about ventilation in this post you can assume we mean how the air comes into, moves around, and exits your condo.

How Does Fresh Air Enter Your Condo?

There are three main ways for fresh air to enter your condo.

  1. A Unit Specific Pump Or Fan. This is most likely to be found on smaller condo units and townhome condos. As the name suggests, each unit has its own, separate system which pumps air into the home. 
  2. A Roof Mounted Fan. The overly simplified explanation for this system is as follows: A giant fan, or fans, are mounted on the roof. They suck fresh air in and push it down through the building. This air enters individual units when doors are opened and closed, through gaps around doors and via tiny, and not so tiny, gaps in the walls and floors of the unit.
  3. Passive Air. In this case, the air is not pumped into the building or into an individual unit. Instead, fresh air gets into a condo when the homeowner opens a door or window to the outside.

Some condos will have one of the first two systems as well as having the opportunity to open doors and windows to the outside.

How Does Stale Air Exit Your Condo?

The majority of the air exiting both a condo building and the individual homes within it will exit via a combination of extractor fans in kitchens and bathrooms and through open doors and windows. Additional air may leak from a single unit through the gaps in and around floors, walls, and ceilings.

Is Air Flowing From My Neighbors Condo Into Mine?

It is unlikely that there is a significant exchange of air between your condo and those of your neighbors.

If air is forced into the building from roof-mounted fans, then that air is pushed down a central ventilation shaft and dispersed via vents on each floor. This air then enters your condo when you open your front door and through small gaps around it. As a result, the sir does not travel into your condo via any of the other condos in the building.


Few homes are perfectly sealed and air can travel from one condo to another through gaps around pipes where they enter and exit the home, as well as via the voids between the walls, floors, and ceilings.

Some condo owners can also experience air bourne smells and contaminates when they have their windows or balcony doors open, allowing smoke or other pollutants to enter their homes.

The temperature, quality, and freshness of the air in your home is dependant on several different factors, each of which may or may not be at play in your condo. So let’s take a quick look at the different systems and processes that will have an impact on the air in your condo.

Do We Share Heated Air With Our Neighbors?

If you are in a smaller condo building of six or fewer floors, or if your condo complex is one of townhomes or individual houses the likelihood is that you will have a heating system which is fo your home only. Consequently, you will not share any air with your neighbors any more than you would in a non-condo home.

Even in a condo building of seven or more floors, the likelihood is that there will be a hot water heating system for the entire property. In order for each home to have control over their heating and cooling, individual condos are usually fitted with a fan type system that pushes air warmed by the hot water in the pipes, around the home.

If you do not have heating controls in your condo and are reliant on a building-wide heating system, it is still most likely to be hot water heating and not forced air.

How Do Smells Get Into My Condo?

The obvious route for smells that carry from one condo to another is through open doors and windows. This can be a particular problem for neighbors when a person on one floor is using their extractor fan when cooking and the person on a floor above has their window open.

But what if you do not have your window or doors open?

In this case, the most likely culprit is a gap or gaps around pipes as they enter or exit your walls or gaps around the door. This is especially likely if the condo units have recirculating air extractor fans in the kitchen and not fans that carry the air outside.

What About The Quality Of The Air?

If you are living in a building built before 1945 you are likely to have better quality air than in more modern buildings.

The reason for this is simple.

Prewar buildings almost always have windows that can be opened to allow fresh air into your condo. Assuming of course that your building is in an area that has fresh air outside!

Postwar buildings, on the other hand, are a different story. The majority of these condo properties have sealed windows and as such, there is limited opportunity for getting fresh air directly into a specific home.

As a result, the air in a taller postwar condo building can become stagnant due to the build-up of environmental contaminants such as carbon dioxide, nitrogen dioxide, sulfur dioxide, carbon monoxide, formaldehyde, ozone, smells, and humidity as well as lead, mold spores and microbial growth, dust, and other chemicals in building, cleaning, and personal care products.

Sick Building Syndrome

In extreme cases, this slow, gradual build-up of stagnant and polluted air can lead to sick building syndrome. The EPA describes Sick Building Syndrome as “situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified.”

In an attempt to minimize 

the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recently revised its ventilation standard to say that building fans must move a minimum of 15 cubic feet per minute (cfm) of outdoor air per person into a building and up to 60 cfm per person may be required in spaces such as smoking lounges.

What Can I Do To Improve Air Quality In My Condo?

In order to ensure the best possible quality of the air in your condo you can do several things:

  • If you have windows and/or doors that open to the outside, use them to allow fresh air into your condo.
  • For condos with an HVAC system that has a filter inside the unit, ensure that you change filters frequently, or if it is the responsibility of the HOA make sure that this is done at the correct frequency.
  • Purchase a stand-alone air filter, preferably with a HEPA filter, to clean the air within your condo.
  • Minimize your use of chemicals in your home.
  • Use your above stove or kitchen extractor fan every time you cook in order to minimize the contaminates from cooking and cleaning products.
  • Always use the fan in your bathroom to remove moisture from the air as well as contaminants from cleaners and personal care products. This will also help to minimize the possibility of mold and microbial growth.
  • Contact your HOA and ask for an air quality assessment of the building and canvas other residents to ensure any recommendations are acted upon.

Final Thoughts

While you are unlikely to share ventilation directly with your condo neighbors you will all, to some degree, be sharing the same air. If you are worried about the quality of the air in your condo you can take measures to improve the quality of air both in your own unit and in the rest of the building.

About The Author

Geoff Southworth is the creator of, the site that helps new homeowners, investors, and homeowners-to-be successfully navigate the complex world of property ownership. Geoff is a real estate investor of 8 years has had experience as a manager of a debt-free, private real estate equity fund, as well as a Registered Nurse in Emergency Trauma and Cardiac Cath Lab Care. As a result, he has developed a unique “people first, business second” approach to real estate.

Check out the Full Author Biography here.


This article has been reviewed by our editorial board and has been approved for publication in accordance with our editorial policy.


Geoff Southworth is the creator of, the site that helps new homeowners, investors, and homeowners-to-be successfully navigate the complex world of property ownership. Geoff is a real estate investor of 8 years has had experience as a manager of a debt-free, private real estate equity fund, as well as a Registered Nurse in Emergency Trauma and Cardiac Cath Lab Care. As a result, he has developed a unique “people first, business second” approach to real estate.

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