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Would blowing a fan on yourself and easing the AC save energy on hot days? Assume we keep the feels-like temperature the same. For example, 23 °C with still air and 28 °C with a fan may feel similar. An aimed box fan on a medium setting shouldn't take much energy, but still provide air movement when the vents are not running (or when you are away from where the vents blow to).

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  • This is why most air conditioners also have fans, surely? They have a certain amount of "must move air to work at all" but most seem to have way more than that, complete with moving louvres and various programs to move those in happy patterns. I have one above my work desk (more accurately, I put my desk in front of/below the aircon), and the cool, dry-ish moving air from that is much better than just being in a cool-ish room. If the "move air through the machine" fan isn't running it's unlike the cooling mechanism is working at all - it would freeze solid quite quickly unless the air is dry.
    – Móż
    Jan 9, 2022 at 1:13
  • So I suppose my short answer is: yes, don't people already do that?
    – Móż
    Jan 9, 2022 at 1:14
  • The question is whether the extra airflow from the fan helps, and if the fan is only blowing directly on the person it wouldn't use much energy. Jan 9, 2022 at 4:44
  • As you move more air (either faster or coving more of your body) there will be a limit after which further increases don't help. But that is specific to your exact situation. Without more information it's not possible to answer whether you will benefit from moving more air. Perhaps you could try it.
    – Móż
    Jan 10, 2022 at 19:47

2 Answers 2

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Depending on the circumstances, using a fan when it is hot instead of air conditioning can reduce electricity consumption, but it depends on both temperature and humidity.

Directing fan forced air onto oneself is similar to the effect a breeze has on a hot day. It's cooling effect derives from the increased ability of sweat to evaporate. As humidity increases the ability of the air to absorb moisture decreases and this decreases the cooling effect of blowing ambient temperature air onto one's body.

During very humid periods refrigerative air conditioning is the only way to be become cool. The disadvantage of using refrigerative air conditioning is that in addition to consuming electricity for the associated fan, electricity is used to compress the refrigerant and pump it to the air conditioning head.

Evaporative air conditioners blow air through a water moist pad to cool. They become less effective in humid conditions because they are adding additional moist air to air that already contains a high degree of moisture. They are best suited to dry inland regions as opposed to coastal regions or areas near large bodies of water.

If you can seek relief using a fan you will be using less electricity.

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  • The question is about when the fan does not provide enough relief and you need AC, if the fan can reduce the AC by letting you get away with a higher temperature. Jan 7, 2022 at 1:35
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Broadly, it will.

AC works on the whole room, house, office or what have you.

Fans work on a comparatively tiny volume.

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