EcoDrain is a small device containing heat-exchange channels. These channels move the heat from warm water running down the drain to the cold water running into the water heater or shower mixing valve.
EcoDrain works with most tankless water heating systems, and the same system can be used for all the showers in your house (provided everyone in the house doesn't decide to take a shower at exactly the same time). It shouldn't affect shower pressure; however, there is a limit to how much water can flow through the system.
There are two types of EcoDrain: vertical (the Upright) and horizontal (the Sleeper). Which one you use depends on the pipes in your shower. The Upright model works only on vertical pipes, while the Sleeper works on either horizontal or inclined pipes. Other types of EcoDrain are in development.
The system is installed under the floor of the shower, and connected directly to the shower drain line. Although EcoDrain is easy to install, it's a job best left to a plumber or contractor.
The EcoDrain can be set up in one of three ways:
- Connected directly to the water heating system
- Connected to the shower mixing valve
- Connected to both the water heating system and the shower mixing valve
The third option saves the most energy, because it preheats water that enters both the water heater and shower. However, it also requires the greatest amount of installation and equipment.
This is how EcoDrain works: As warm water leaves the shower, clean, cold water circulates around it. Inserts called turbulators increase the rate of heat transfer by generating turbulence in the water.
Don't be alarmed about your dirty shower water mingling with clean water from the pipes. The dirty and clean water come into close proximity, but they never mix because there is a double wall separating them -- the warm water simply transfers its heat to the cold water. Even if a hole were to form in this wall, the dirty and clean water would still not mix, because EcoDrain contains a vent that would send the dirty water harmlessly to the outside of the building.