Why Do Open Windows Make Doors Slam?

25 February, 2020

How annoying is to have your peace and tranquillity broken by a slamming door? Most of us have been scolded for slamming doors while we were in a strop in our teenage years, but doors can also slam on their own. It could be the simplest of reasons - because of open windows.

We’ve been examining the science which causes this to happen which is all about the movement of air.

Windows Cool Your Home

Open your windows on a sunny day and you’ll be airing your house which in turn will make you feel more comfortable. It’s the cheapest and most effective way of cooling your house and if the windows are on different sides of the building, natural breezes will pass through. This is known as cross ventilation and can help to get rid of stale air.

As air moves through your house it can remove pollutants, odours and moisture. Open the windows at night and the cooler temperatures outside will help to reduce the heat internally. Ventilation and a flow of air distribution makes your home more comfortable to live in.

So, while we know there are so many benefits from opening your windows, why does throwing open the windows encourage doors to slam shut if they’re ajar?

Air Pressure

Imagine a house as just a big hollow box which is filled with air. The doors within the house swing open and shut and generally we do this ourselves to create the force for this movement, but air movement can also create this force.

If you’re in a room and the windows are shut, there’s minimal air movement. The effect of displacing air requires more force because that air is contained.

The more windows open the more force which exists. Opening a window means wind blows through and looks to find a path through the house. When it goes through and past a door it provides the force needed to slam it shut. The air flows freely, with the area of low pressure behind the door in that room equal to the rush of outside air which means resistance is reduced, allowing the door to swing closed easily.

Creating A Vacuum Inside

Turn this on its head. If a window is open, window blowing past an open window can suck air from the house. Air rushing past an open window creates a low pressure at the window. This then drags air out of the window creating a vacuum inside the house. This can then cause air movement through the house, in turn slamming doors. This is known as the Bernoulli effect.

For all your door needs come and speak to the experts at Door Stop. Whether you’re after internal or external doors, we have a range to suit your tastes. You’ll be impressed with our turnaround times. We can have them delivered, installed, weather sealed with locks included, all at a competitive, affordable price within days. Pick up the phone and call us today or visit us at our showroom in Osborne Park or Joondalup and speak to our friendly team.

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