Greywater heat recovery / Green Building & Sustainable Home Renovation Information & Advice

...heat recovery: a homeowner's & pro's guide Drain water heat recovery (DWHR) is a passive energy-saving technology that captures heat from gray water before it disappears down the sewer. In a typical home, heating water is often the second largest energy expense after space heating. By using a heat exchanger to preh...

...greywater heat recovery that looks quite promising.  If you aren't familiar with the term, greywater heat recovery devices, as their name suggests, are used to recover heat from drain water before it is discharged from homes. In order to work they require water tanks to be filling while hot water is draining, so the fu...