ON A hot July day in 1902, the world’s first air conditioner was switched on in Brooklyn. Since then, air conditioning has saved lives, raised productivity and made the American South liveable in the summer. Yet as it turns 110, critics fume that the technology cooks the planet even as it cools homes. As Stan Cox points out in his book, “Losing Our Cool: Uncomfortable Truths About Our Air-Conditioned World”, America uses more energy for air conditioning than Africa uses for everything. Enter Advantix Systems, a firm that makes air-conditioning systems that consume 30-50% less energy than conventional ones.

Many air conditioners work something like this. First, cool the air to well below the desired room temperature. Then, blow it over a metal plate to make the moisture in it condense (and rain on the heads of passers-by, if the cooler is in New York). Then, warm the dry air back up to the desired temperature.

Advantix’s “liquid desiccant” technology, by contrast, passes the air through a brine solution to dehumidify it, without the need to waste energy overcooling it. Its machines are especially effective in humid places, which is where much of the world’s growth is.

Advantix, which used to be known as DuCool, stumbled on the technology. It was founded in the 1980s by Israeli brothers who built ice rinks in the Middle East. They found that many coolers could not cope well with the humidity there, so they created ones that could. MatlinPatterson, a private-equity firm, bought a stake in 2010 and brought in managers who concocted an ambitious plan to sell cooling systems for commercial and industrial buildings. Advantix recently announced a big deal to air condition a Procter & Gamble factory in India that makes laundry liquid pods.

Competition will soon heat up, however, as rivals develop their own liquid desiccant air conditioners. In this business, you have to sweat to keep up.