What Is An Aircon Vent? (Should It Be Open or Closed?)

If you look closely on the blower louver of your aircon, you’ll notice a black lever that, when toggled, will open or close a panel at the back of your air conditioner. This thing is called the aircon vent, and it can be opened or closed depending on your preference. But when should you toggle it, and why?

Closing the aircon vent will prevent warm air from the outdoors from inside your room. If you are conscious about energy efficiency, you should keep the vent in the closed position for most of the time. Meanwhile, opening it will let warm air inside your room which will increase the temperature, with the trade off being an influx of fresh air to refresh the stale air inside your room.

In this article, we will discuss the purpose of the air vent and when and when not to open it.

What is an aircon vent for?

The aircon vent is a small opening inside the air conditioner that lets fresh air from the outdoors to come in and refresh the stale air in your room. This is also helpful when you want to exhaust out any smoke or unpleasant odor from your room.

You can toggle the aircon vent open or closed depending on your situation.

Where can I find the aircon vent?

aircon vent

The vent can be seen mostly on window air conditioner models. While the vent itself is located at the back of the unit, the vent lever is usually protruding on the blower louver panel.

For newer models, the lever may not be present, instead a button that says “EXHAUST” will replace it.

Does a split type have a vent?

No, a split type AC does not have an air vent. However, opening a few windows is a good alternative if you want to refresh the air in your room.

When to open the aircon vent

It may be counter-intuitive to open the vent during operation. After all, didn’t you just spend money to keep the cold air inside your room? But there are several reasons why you should open the aircon vent.

Replacing stale air

When the windows in your room are closed for an extended period of time, the air will get stale as it gets recycled on and on by your air conditioner.

While this may seem like a mild nuisance, it can actually cause you harm.

Stale air is full of microbial volatile organic compounds (MVOCs), which can cause headaches, coughing, fatigue, and ENT (eyes, nose, throat) irritation. They can also emit unpleasant odors at high volumes.

Thus, when you start to sense that your room has become stale, either open the aircon vent, or open a few windows to let fresh air in.

Removing odors from a room

If you find that the air in your room smells funky, you should open the aircon vent to exhaust the odors out of your room.

You should also open the vents if smoke somehow finds its way to your room.


In most cases, keeping the aircon vents closed is a good idea as it saves energy and keeps the cold air from escaping from your room. However, if you are in an office or a classroom where the windows are almost always closed, you should open the vents from time to time to supply you with fresh air.


  • Bernstein, J., MD, Alexis, N., PhD, Bacchus, H., NP, Bernstein, I. L., MD, Fritz, P., BS, Horner, E., PhD, Li, N., PhD, Mason, S., PhD, Nel, A., MD, PhD, Oulette, J., PhD, Reijula, K., MD, Reponen, T., PhD, Seltzer, J., MD, Smith, A., PhD, & Tarlo, S., MBBS. (2008). The health effects of nonindustrial indoor air pollution. The Journal of Allergy and Clinical Immunology, 121(3), 1–6. https://doi.org/10.1016/j.jaci.2007.10.045
  • Poslusny, K. (2019, March 1). What is Stale Air? It’s Actually Chemicals Like CO2 and MVOCs. Molekule Blog. https://molekule.science/what-is-stale-air/

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