Ever experienced sudden slamming of doors and windows? A strange whoosh and whistle sound? Light objects automatically getting an outward flow? All of this, if it happens when you’re with the rest of the members may not scare you but imagine yourself completely alone at home and the doors and windows start to bang! Huh! Scary, very scary! The only thought that this occurrence will give you would be; ‘’I need to call a ghostbuster as early as possible’’. Interestingly, for such an issue, the right person to call is an HVAC professional. This type of occurrences take place as a result of improper air pressure. It could be a negative air pressure or a positive air pressure; anything but a normal air pressure. The symptoms may include;

* Uneven temperature in different parts of home
* Sudden slamming of doors and windows
* Easy to open doors/windows requiring unnecessary energy
* Strange noises (whoosh, whistling)
* Doors, windows getting automatically open
* Differentiating positive and negative air pressure


When you have a high indoor pressure and the air rushes from inside towards outside, it is the positive air pressure. As a result of such pressure, the doors/windows open outwardly on their own. Also, as there’s a high indoor pressure, it may make the opening of windows/doors difficult from outside.

Negative air pressure, on the other hand, is a scenario in which the outdoor air pressure is higher than the indoor air pressure. In other words, there’s insufficient air pressure in the indoors. As air moves from higher pressure towards lower pressure, the indoors will suck the outer air resulting in inward opening/slamming of doors/windows and overburdening of the HVAC system as it has to counteract with higher and more pressure.

Why does pressure go out of balance?


The question is; why in the first place, does the indoor air pressure go out of control? Here are the reasons;

1. Hot air consequences:


Hot air rises, remember that first hot air balloon experiment from primary school? The phenomenon of negative air pressure often takes place in winters as the hot air accumulates the indoors. The hot air rises to the upper portions or evacuates through vents and chimneys, leaving a low air pressure behind. As a result, the air pressure imbalance takes place.

2. Effect of exhaust fans


Exhausts fans help expel the undesirable air but they may perform over efficiently and expel so much air so as to cause a negative air pressure in the indoor.

3. Duct leaks


Leaking ducts compromise air pressure. They will overly supply air to the enclosed areas while leaving the open areas with an insufficient supply of air. This will result in negative air pressure in the open areas and positive air pressure in the enclosed areas.

4. Fan speed


While you may look here and there to find the cause of improper air balance, it could be in the speed of your Air Conditioner/Furnace fan. A very high speed of the fan will push more air towards the indoors through ducts, resulting in positive air pressure.

Many homeowners live under constantly imbalanced air pressure and never bother to balance it. The fact is, an improper and unbalanced air pressure will not only give you scary instances when you are home alone, it also has the potential to affect the HVAC system by overburdening it (as explained above).

If you figure out that you are living under positive or negative air pressure, make no delay and fix the problem by calling an HVAC professional as soon as possible.

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