Hot hot hot

25 April 2006
3:55 PM

Flaming calefon
The gas ignites in our house calefón.

Before I left the U.S., I lamented my loss of hot showers. In retrospect I’m not sure why—my complaints really didn’t have any factual basis. We have hot water here and therefore hot showers, although a few of the people who live in this area do not. What we don’t have is a traditional water heater. What we do have is a clever thing called a calefón.

The calefón hangs on the wall in the kitchen. It’s an on-demand water heater connected to a 15kg tank of natural gas that we buy from roaming gas trucks. Our calefón consists of a grid of gas burners and twisting water pipes that pass water above the burners. When we want hot water, whether for a shower, washing dishes, or doing laundry, we strike a match, light the pilot, and lift the lever that controls the gas flow.

The cool part doesn’t come until you turn on the water, though. When that happens, the pressure from the water flowing through the calefón pushes on a pin that regulates the flow of gas to the burners. Next comes a sleek and whooshing explosion as the gas ignites. Almost instantly you get hot water where you want it.

Calefón lighting when water is turned on

Sometimes the water is too hot, which leads me to an interesting and counterintuitive technique with the calefón system. The water is heated as it flows through the pipes above the calefón’s burners. Turning up the water increases the rate of water flow through the heater and therefore decreases the resulting temperature. So when you’re in a scalding shower, turn up the hot water and you’ll cool down fast. If that makes sense.