Mystery of the Hot Water

One of the interesting things about our apartment in Cologne is that for the first time, we don’t have a hot water heater.

From what I can tell, older apartment buildings here in Germany still rely on those large building-wide water heaters for both the heat and the hot water, but newer buildings, or buildings that have just gone through renovation, now use these instant water heaters. They’re supposedly very energy efficient – they kick in as cold water flows through and instantly heats it up to anywhere from 60 – 85 degrees (celsius) – and in the bathroom, the one we have is fantastic, giving us great hot water for as long as we need it.

Fast forward to Friday. The kitchen installers hook everything up, including the connection to the similar water heater in the kitchen. We flip the switch and boom – hot water. Great.

However, about two minutes later, no more hot water. Turn off the water for 2 minutes, turn it back on, and boom. Hot water… again for about two minutes. Look up instant water heaters on the web. Nothing describes this kind of problem… but it is consistant. We get scalding hot water for a few minutes, and then back to cold, until we turn the water off for 2 minutes. Needless to say, since we can get a full hour’s worth or more hot water from the bathroom, we were very confused.

Late last night, Janet and I figured out what was going on (surprisingly, we were working off of the same idea independantly and came to the same conclusion). The bathroom instant water heater is a more expensive model that gives unlimited hot water. The one in the kitchen is actually a 5 liter mini-hot water heater designed for light usage like rinsing a cup or something similar. Since most houses here have dishwashers (they are more energy and water efficient, they heat their own water, and wash a whole load of dishes in less than 18 liters), in the kitchen you only need a very small amount of hot water. Enter the 5 liter water heater: enough or small tasks, but not enough to wash a full load of dishes.

Just another fleeting moment of feeling like a true cultural auslander.