Air flow stairwell

[moby25]

Bonjour à tous

here I discovered that I had a feeling of fresh air when I climbed into my stairwell.

This air is located at ground level of the upper floor. In fact I feel it when my head is located when climbing to ground level.

By placing a candle I noticed that the flame was almost horizontal.

Here is a diagram explaining the situation better.



By placing a Thermometer at this level I realized that it was very cool.

Is this draft normal in a stairwell?
In fact I break my head looking for where comes the faster loss of T ° C of the room which overlooks this cage compared to the neighboring room which loses less quickly (more than 1 ° C difference) .

So I wonder if it could have come from there.

[oiseautempete]

Bonjour à tous

here I discovered that I had a feeling of fresh air when I climbed into my stairwell.

Is this draft normal in a stairwell?
In fact I break my head looking for where comes the faster loss of T ° C of the room which overlooks this cage compared to the neighboring room which loses less quickly (more than 1 ° C difference) .

So I wonder if it could have come from there.

Yes, this phenomenon is perfectly normal: it's called convection and it comes from the difference in temperature between the hot bottom and the top, which is probably cooler.
We can avoid this by putting a heavy curtain at the bottom of the stairs to stop the movement of air ...
We have the same phenomenon with a mezzanine.

[dedeleco]

Also having a staircase, I do not see a convection current as detectable and therefore as intense on a candle flame.
In my opinion, you have a cold zone at the level of the ceiling which reinforces this convection current by cooling the hot air from the bottom which rises and then it comes down very cold !!
So I advise you to research if you do not have a cold area on the ceiling due to the lack of insulation in your attic or roof on a small area.
You are looking for the area where your hot air cools and then descends.

[moby25]

Thank you for your answers.

It is not easy to know, in fact when I go up the stairs, at the beginning I have this hot flash which is due to the heating, and just after a feeling of cold.

But I think that the difference of T ° C floor and ground floor has a lot to do with it, because yesterday with the sun, it was warmer yesterday in the rooms and there was no longer that feeling.

I also looked for a cold wall in the cage, but I couldn't find anything.

[Christophe]

Uh computer question: is there not a problem with the diagram because it is "half" white?