What is cross ventilation in construction?

Written by LetsBuild

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When it comes to buildings, cross ventilation is very necessary, because the air inside needs to be replenished and circulated frequently.  While you can use any type of ventilation to accomplish this, cross ventilation is usually the best.

When talking about cross ventilation, you must have entrances and exits for the air.  The pressure of the air that is entering must also be different than the pressure of the air that is leaving.  This can be accomplished by two openings on opposite sides of the building.

If you have never thought about why cross ventilation is necessary, let’s dive into the reasons why the air needs to circulate.  First, stale air holds a lot of moisture, which can cause mold and smell quite bad.  Irritants and allergens can build up as well, which can affect the health of those that are in the building.  The cross ventilation will also moderate the internal temperature of the building.

The most common options for cross ventilation in construction are windows and wall vents.  Those items can simply be opened to create natural ventilation.  If those items are not available, then mechanical ventilation, which is forced ventilation, will be needed.

When to Use Cross Ventilation in Buildings

There are times when cross ventilation is quite helpful in buildings and those scenarios include:

  • Narrow buildings
  • Exposed Sites
  • Buildings that are perpendicular to the prevailing wind
  • There is regular distribution of openings
  • There are no internal barriers to interrupt the air flow

When to Consider Other Options Instead of Cross Ventilation

There are times when cross ventilation is not going to be your best option when it comes to moving air throughout a building and those scenarios will include:

  • Internal walls and partitions are blocking the flow of air
  • Buildings that are too deep to ventilate from the perimeter walls
  • The building is sheltered from the wind
  • The air quality outside is not that good
  • Very loud noise on the outside will prevent windows from being open
  • Security or privacy issues prevent the windows from being open

When you are preparing to install cross ventilation in any building, you must first determine which direction the wind will be blowing from most of the time.  This knowledge will allow you to then determine where all the inlet and exhaust vents should be placed.

If you do not think that you will have enough difference in pressure for the entering and exiting air flow, you may want to consider installing additional cross ventilation products.  Specialty wall fans can be helpful, as can wall louvers and other natural ventilators.

Natural cross ventilation is usually the best option, but it is important to note that the behavior of the people inside the building can influence the outcome of the ventilation you have in place.  Anyone can close an open window if they feel cold, or warm, and that closed window will affect the results of the ventilation you are trying to achieve.  Therefore, training or at least having a class on what behaviors are expected is necessary to ensure the ventilation works as it should.

Of course, you can always install automated ventilation, but that means that the people inside the building have no control over the surrounding conditions.  If a person gets warm, they cannot simply open a window to cool off.  Some people will not like this, and it may cause them to not want to be inside the building.

It is normally best to have both natural and automated cross ventilation in place, so that you can guarantee that air will continuously move throughout the building.  This will ensure that people can open and close windows as they wish, and the automated cross ventilation will work as a backup method to keep the air circulating inside.

7 Benefits of Cross Ventilation

  1. You will use a lot less energy on those hotter days of the year, because you will not need to run your air conditioner for as long.
  2. The temperature inside the rooms of the building will be much lower, which is perfect during the summer months.
  3. Cross ventilation requires no maintenance, which means that there is no cost in upkeep or usage. This is much better than the cost of installing an air conditioner unit and maintaining it.
  4. Air will continue to enter the building twenty-four hours a day and you never need to make sure to turn anything on or off.
  5. There are less health issues for those people who spend time in buildings that have excellent cross ventilation.
  6. Since the air inside the building is not stale, people can easily breathe fresh air whenever they want.
  7. There are no harmful gases emitted with cross ventilation, which is better for those people inside the building and also for the environment.

While it is always best to have multiple windows on opposite sides of a building for cross ventilation, you can easily achieve the same goal with only single windows or one window in the room.  Yes, you would need to install fans, or some other type of automated ventilation, but that would be better than all the stale air that would be floating around otherwise.

All buildings, and homes, need cross ventilation, so this is a good time to brush up on your skills and see how to incorporate the best ventilation that you can in everything that you construct.  The more ventilation you include will mean the better results for those people who are inside the buildings, or homes, now and in the future.