To avoid running the tap—and pouring water and money down the drain—the Lais installed a Rinnai tankless water heater and Metlund D’MAND recirculating pump for near-instant hot water. When David or Mayuko enter the Miele-outfitted kitchen, a sensor triggers the systems, readying the water to flow out of the faucets at piping-hot temperatures four to five times more quickly than without the setup.  Photo 2 of 13 in A Dream House for the Ages