Energy down the drain is not a myth. We noticed on social media that sceptics are saying that the hot water temperature from the shower rose drops by as much as 15°C by the time it enters the waste plug. We believe they should get their thermometer checked over. We measured the drop to be only 3.5 to 4.7°C and these readings were from the rose through the trap to the entry pipe of the HeatBack unit. Unless you’re taking cold showers, there’s still plenty of heat to recover.