The Europeans always seem to be coming up with the bright ideas of sustainability, and while their latest may seem like one of the sketchiest, it’s definitely one of the smartest.

Some clever Austrians in the town of Amstetten have decided to “recycle” the energy from hot water in the sewers to help heat buildings using a special tech installation in the pipes below the city.

Water running in pipes adjacent to — but separated from — the sewer is warmed by devices called heat exchangers that “suck” the warmth out.

This warmed water is then pumped to the nearby headquarters where a highly efficient heat pump fires the central heating system.

Smart – as there’s a lot of “wasted” hot water literally going down the drain from kitchen appliances, companies and other places, so why not put it to good use!?

But is it clean?

The water that is pumped over here is clean, there is no fecal matter. The equipment inside (the sewer) is also self-cleaning.

Read the full story on Yahoo News.