Air Conditioning - Should One Window Be Left Open in the Home?
In short, the answer to this question is No! All windows and outside doors should be shut whilst the air conditioning is operating for the following reasons:
1. Air conditioning systems are specifically designed, sized and installed to distribute the correct quantity and quality of air to the home. Leaving a window open will affect the loading of the A/C unit.
2. The efficiency of the home air conditioning unit depends on the system of fans and ducting being carefully balanced, normally by a professional HVACR engineer. Leaving a window open will alter these settings, lowering the system’s efficiency.
3. As can be seen from my diagram, on modern A/C systems an air filter and/or an air purifier are incorporated in the discharge ductwork. The filter is imperative to remove dust particles or pollen, whilst the purifier can have a UV/catalyst that removes any chemicals or odors. These components are essential if anyone in the family suffers from allergies such as hay fever or asthma. Leaving a window open will introduce dust/odors/pollen from the garden into the house and into the air conditioning system.
4. The de-humidifier removes the moisture from the airstream. This prevents dampness, condensation and damage to electrical appliances and electronics. It also makes the living quarters more comfortable for the family. Leaving a window open will reintroduce moisture to the system and home.
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