> A DWHR unit consists of copper pipe tightly wound around a vertical section of copper drainpipe. As water flows down the drainpipe, it clings to the inside surface of the drainpipe. The heat from the drain water is transferred through the copper drainpipe to fresh cold water flowing in the outer copper coil.
> The warmed water is then sent either to the hot water tank or other permitted end-use. In either case, the amount of energy needed to provide hot water is reduced. DWHR systems provide greater potential for energy savings as the number of simultaneous flows increases.
You wouldn't necessarily need this on every waste water egress. In my house, I've got one shower egress route that it would make sense on. The kitchen (I don't have a dish washer) doesn't run hot water for long enough for it to be reasonable - nor the 2nd floor bathroom with just a toilet and sink.
(edit)
There are spots where (in my house for example), this could be more useful. For example, that 2nd floor bathroom I've looked at a tankless water heater for the sink (so that I don't have to pull hot water from far away and then could simplify to only need to run cold water). Capturing the hot water there and returning the heat there there may make some sense... though for just a sink that would be a long ROI time.
> A DWHR unit consists of copper pipe tightly wound around a vertical section of copper drainpipe. As water flows down the drainpipe, it clings to the inside surface of the drainpipe. The heat from the drain water is transferred through the copper drainpipe to fresh cold water flowing in the outer copper coil.
> The warmed water is then sent either to the hot water tank or other permitted end-use. In either case, the amount of energy needed to provide hot water is reduced. DWHR systems provide greater potential for energy savings as the number of simultaneous flows increases.
The Home Depot version: https://www.homedepot.com/p/Power-Pipe-3-in-x-48-in-Drain-Wa...
You wouldn't necessarily need this on every waste water egress. In my house, I've got one shower egress route that it would make sense on. The kitchen (I don't have a dish washer) doesn't run hot water for long enough for it to be reasonable - nor the 2nd floor bathroom with just a toilet and sink.
(edit)
There are spots where (in my house for example), this could be more useful. For example, that 2nd floor bathroom I've looked at a tankless water heater for the sink (so that I don't have to pull hot water from far away and then could simplify to only need to run cold water). Capturing the hot water there and returning the heat there there may make some sense... though for just a sink that would be a long ROI time.