I thought I should give Norwegian websites a try in my urge for finding a small heat exchanger for our shower. To my surprise, a new product had just been introduced to the Norwegian market by http://www.miljodusj.no/ (Norwegian only). (It should also be available in Austria, Slovakia and Germany. More information on the product can be found at the SUP technology site in the Czech Republic http://www.sakal-ovt.cz/eng/shower.htm ). There it was. Just what I had been looking for. I talked to the salesperson who explained a bit more how it worked. Cold water from the house pipe connects to 1. Drainwater from the shower flows into 4 and heats the copperpipes of coldwater inside the box, before it exits out and down the drain at 3. Preheated cold water will exit from 2 and on to cold water pipe of the shower. The salesperson said the coldwater would increase 12-15 C (53-59F). He claimed it to be actual measured numbers.
I ordered it and prepered to put it to the test.
Continue reading here: 3.Looking inside the heat exchanger