Drafts

[thornabylad]

Hi,

If you leave our living room door ajar and hold your hand against the gap, you feel a gale force wind blowing through the gap from the hall and yet when you stand in the hall you cannot feel any drafts.

We have gas central heating, cavity wall and loft insulation, we also have double glazing and upvc front and back doors.

Does anyone have an explanation as to why this happens. Where is the gale coming from?

Cheers

John

 

[masona]

Yes,difference temperature in difference room and the most common problem is the draught coming through the hall way depending on your central heating radiators layout.If you turn up the heat full blast you will not get this problem but big gas bills instead

 

[breezer]

actually it is called the "venturi effect"

to get a set amount of gas or liquid (air in this case) through a small gap (the door being a jar, hence small gap) the gas or liquid has to speed up to get through the gap as it is restricted through the gap, so you feel a "gale force" wind when the door is a jar but if you open the door you feel nothing.

the reason you get it in the first place is the temerature difference between the two rooms.

This "useless" fact is also used by many koi keepers (koi the fish) to oxygenate the water by fitting a venturi to the return pipe of their filter pump, the restriction in the venturi sucks air into the venturi pipe oxygenating it. It is also used in fountainsto make "frothy nozzles"

dont believe me see here and this (look near the bottom of page)

 

[thornabylad]

Cheers guys, that's very helpful.

I did think it had to do with difference in room temp, but I wasn't sure