Did you know that the humble ceiling fan is the best defense against the sweltering heat that has swept across the country? When we feel hot our first reaction is to turn the air conditioner on. But a ceiling fan used along with the air conditioner can make the room feel comfortable faster and also help reduce your electricity bill.

Let us explain how. The normal temperature of the human body is around 37 deg celsius. In the summers when the temperatures increase, the body cools itself down by sweating or by releasing water through evaporation to the surrounding air. But this only works when the humidity levels are low. But as soon as humidity increases sweating does not work, making us feel uncomfortable and sick. This is because the air already has enough moisture and is slow or unable to absorb any more water than our body is releasing.

But here the fan can help. Although a fan does not cool its surroundings, the draft of air that it pushes can help remove hot air from over the skin and help in evaporation of the sweat making you feel comfortable. We know that air conditioners are energy guzzlers and very bad for the environment. But the impacts of air conditioners can be reduced when used along with a fan. India’s Bureau of Energy Efficiency or BEE says that the cooling effect of an air conditioner plus a ceiling fan with its thermostat set at 26 deg celsius is the same as an unaided air conditioner running at 22 degrees celsius. The energy savings of the air conditioner plus fan could be as high 12-20%. So it makes sense to switch on a fan along with the air conditioner.

Down to Earth is Science and Environment fortnightly published by the Society for Environmental Communication, New Delhi. We publish news and analysis on issues that deal with sustainable development, which we scan through the eyes of science and environment.

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