Should I close the door when running AC in fan mode

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Discussion Overview

The discussion revolves around whether to keep the door closed or open while running an air conditioning unit in fan mode within a specific room and bathroom setup. Participants explore the implications of air circulation, pressure differences, and the potential benefits of introducing outside air.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that fan mode only circulates the air within the room and does not bring in outside air.
  • There is a question about which door is being opened: the door to the outside or the door to the bathroom, with implications for air flow and pressure.
  • One participant notes that opening the outside door may not be beneficial depending on the current temperature and humidity conditions.
  • Another participant mentions that the effectiveness of bringing in outside air can vary based on the specific circumstances.
  • There is curiosity about the benefits of opening versus closing the door while running the AC in fan mode.
  • A suggestion is made to simulate airflow scenarios using software like SimScale for better understanding.

Areas of Agreement / Disagreement

Participants express differing views on the effects of opening the door while running the AC in fan mode, with no consensus reached on the best approach. Some agree on the mechanics of air circulation, while others highlight the importance of external conditions.

Contextual Notes

Participants note the lack of information regarding temperature and humidity, which could significantly influence the discussion. The specific layout of the room and the presence of a wall and window are also mentioned as relevant factors.

Who May Find This Useful

Individuals interested in HVAC systems, air circulation dynamics, or those facing similar questions about air conditioning usage in confined spaces may find this discussion relevant.

Altiano
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I have a 3x3.5 (meters) room with a bathroom of approximately 1.5 x 2.
I want to know whether to close the door or not, If I running Fan Mode.
There is wall in front of my door, about 60 cm,

My assumption: Fan mode only circulate the air, If I open the door, I'll bring outside air in, which is better than just inside air
 
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I have not heard before of a fan mode in a bathroom.
In my own bathroom there is an extractor fan; the fan goes on when the light is on,
(that is, somebody is using the bathroom)
Opening a door or closing it will not make a lot of difference to the flow of air.
Air is gases; gases flow from higher pressure to lower pressure and solid objects usually don't stop it. gas finds a way around it.
 
Last edited:
Altiano said:
I have a 3x3.5 (meters) room with a bathroom of approximately 1.5 x 2.
I want to know whether to close the door or not, If I running Fan Mode.
There is wall in front of my door, about 60 cm,

My assumption: Fan mode only circulate the air, If I open the door, I'll bring outside air in, which is better than just inside air
There are some things that aren't clear to me, but I'll give this a shot:
1. Yes, "fan mode" just re-circulates. It does not bring in outside air.
2. What door are you opening? Door to outside or door to bathroom. If it is the door to the bathroom, I don't see why outside air will come in. If it is the door to outside, sure, air will come in, but your system's "fan mode" won't affect that.
3. Sometimes bringing in outside air is useful and sometimes it isn't.
 
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Your OP doesn't mention temperature or humidity at all (inside or out) so really impossible to know what you are trying to achieve.

Where I live opening an outside door is currently a bad idea, but in 5-6 hours it will be a fabulous idea, I can't wait.
 
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russ_watters said:
There are some things that aren't clear to me, but I'll give this a shot:
1. Yes, "fan mode" just re-circulates. It does not bring in outside air.
2. What door are you opening? Door to outside or door to bathroom. If it is the door to the bathroom, I don't see why outside air will come in. If it is the door to outside, sure, air will come in, but your system's "fan mode" won't affect that.
3. Sometimes bringing in outside air is useful and sometimes it isn't.

Okay, I'll try to explain a little bit more of the room,
- There are no windows in the room
- What I open is the door to the outside
- Not really "outside (like open field)", because the room is in the (boarding) house.
- In front of that door is a wall, on the right about 20cm, is a window.

Actually I am curious to know what are the benefits for opening the door and closing the door when running on "Fan Mode".

CWatters said:
Your OP doesn't mention temperature or humidity at all (inside or out) so really impossible to know what you are trying to achieve.

Where I live opening an outside door is currently a bad idea, but in 5-6 hours it will be a fabulous idea, I can't wait.

Just want to know what will happen in 5-6 hours? :)
 
Altiano said:
Just want to know what will happen in 5-6 hours? :)

The sun sets and it gets cooler outside than inside.
 
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If you want to go for an overkill solution, you can try and simulate it with SimScale. There are examples that are similar to yours like the airflow in an office space.

You can get sign up and create a free account and try things.
 

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