The air-conditioning is a large contributor in the electricity usage in the school, as it uses far more electricity than its close substitute, the fan. According to a New York Times report, a 2.5-ton central air conditioner uses about 3,500 watts, a window A/C unit typically uses between 500 to 1,500 watts, while a ceiling fan uses only 15 to 95 watts. The fan uses 5 to 100 times less energy than the air-conditioner. Therefore, it is crucial to reduce aircon usage in order to reduce greenhouse gas emission, thus slowing down global warming.