Hot water down the drain seems like a waste of energy, right? Well, a low-tech product called EcoDrain is aiming to recapture that energy by placing a heat exchange device between your outgoing shower waste drain and your incoming hot and cold water lines...
The EcoDrain system is fairly simple: The EcoDrain is installed directly in the shower drain line and features a double wall of separation between fresh and wastewater. The incoming fresh water recaptures the heat of the wastewater as they cross each other in the heat exchanger – the two never mix because of the double wall system. The system can be configured in three different ways: 1) Preheated water goes directly to water heater, 2) Preheated water goes to both the water heater and shower mixing valve, or 3) Preheated water goes directly to shower mixing valve only. Either way, less energy is used to heat water through the water heater – so much that the company claims to save water heater use by 40%.
Waste water heat exchangers are not a new concept – people have been wrapping cold water copper pipes around drain lines for years, but the EcoDrain aims to be more efficient with a better design to capture more heat.
While we couldn't find exact pricing info for the EcoDrain, it seems like it would be difficult to justify the amount of work involved for a residential retrofit, but the system is a no-brainer for a bathroom remodel or new construction. The EcoDrain is currently only available in Canada, but according to the company's website, they're in the process of making it available to the US and abroad.