Want to Use Less Air Conditioning? Just Turn on a Fan

tech.hindustantimes.com:

Earlier this year, the UK attempted to go coal-free. But an increased need for air conditioning forced the usually temperate country to reverse itself and restart an old coal-fired power plant — after only 46 days.

This is a cycle that's likely to get more vicious as hotter weather leads to more air conditioning, which exacerbates both global warming and urban heat islands. But maybe we don't need nearly as much AC as we think.

The answer isn't to suffer in pools of sweat but to use scientific knowledge about human physiology to stay just as cool with a lot less AC. Scientists say we can use about 70% less air conditioning and achieve the same comfort level by increasing air flow with ordinary electric fans.

This makes intuitive sense, as most of us feel uncomfortable in a stuffy room at 80F, but deliciously comfortable at that same temperature in a breezy park or outdoor café.

Researchers in Australia and the US have shown how this works and calculated how it could reduce air conditioning costs.

Ollie Jay, director of the Heat and Health Research Incubator at the University of Sydney, says you can measure comfort scientifically with a seven-point scale. Zero is neutral, -1 is slightly cool and 1 is slightly warm. While comfort levels vary from one person to the next, the percent of people who report being uncomfortable increases as the scale gets further from zero.

Using this scale, Jay and his colleagues showed that fans can make 82 feel just as nice as 72 while using about one-thirtieth the energy. That could have big implications for offices and hotels in the US.

Jay pointed to an article that just ran in The New York Times touting a new kind of white paint that could, in theory, reflect more sunlight off roofs and save 40%