The principle

The shower water is usually still more than 35°C when it runs down the drain as waste water. The hot shower recovers this residual heat to preheat the cold fresh water! No electricity is needed for this! The shower heater extracts the remaining heat energy from the waste water and transfers it to the cold water that flows through the shower heater. This immediately saves energy. The shower heater is an extension of the cold water pipe. The cold water (blue) is led through the right-hand hose into the shower heater. It comes out as preheated cold water (red) and is mixed with hot water in the mixer tap. Then it comes out of your shower head as usual. This means you need 20-40 % less hot water.

Important!: The hot shower head is a diversion and extension of the cold water pipe, no pump or the like is necessary!

The heat exchanger

The heat exchanger is the main part on the hot shower and is essentially two stainless steel plates welded together. Between the plates, there are channels between the special embossments through which the water can flow. At the ends of the channel are welded special sockets to which the hoses can be attached. The heat exchanger is made of very thin sheets to allow the best possible heat transfer. It is robust, stainless and easily withstands the pressure of the water, thus meeting the requirements of DVGW.

The mixer tap

Usually in showers, it looks like the shower water is mixed in a mixer tap. Hot and cold water come out of the wall and in the shower, the mixer tap can be used to determine how hot the water gets, that is, how much hot and cold water is mixed. A mixer tap often looks like this, or something like this:


The mixer tap with adapter

We pass the cold fresh water coming out of the wall through the heat exchanger once before it then flows back into the mixer tap. The adapter interrupts the flow of water in front of your mixer tap. The cold water passes through the heat exchanger once, onto which the warm shower water pours. This warms up the cold water running through the heat exchanger a bit, and then it is fed back into the mixer tap as preheated cold water. So could your Mischabtterie with adapters then look like:

The adapter

For the hot shower to work, you'll need to disassemble the mixer tap in the shower once and screw our special adapter to the cold water supply line and a spacer to the hot water supply line. On our adapter there is a small inlet and an outlet in which we install quick couplings for our 8mm hoses ex works. You then connect the hoses to the hot shower. Easy or not?! For even more info just check out our blog: How does it work with the special adapter?


In your shower, it might look something like this: