Hot jets of water blasting your scalp and massaging the back of your neck while you belt out a few tunes … few activities are as relaxing as a long, hot shower.
But in drought-stricken areas where water is scarce, and in a warming world where carbon dioxide produced from burning fossil fuels is ramping up climate change, standing under a steamy shower longer than the minimum cleaning time carries a certain stigma.
Now, a team of Finnish designers claims to have solved the problem: a build-it-yourself kit called the Showerloop that cleans used water and pumps it back up to the showerhead.
It works by sending the water through five filters. The first sieves out big chunks of stuff, such as hair. The water is then pumped to a mesh filter, then trickles through a layer of sand, which scoops out few remaining particles.
A layer of charcoal clarifies the water, removing smell and chemicals, and a final blast of ultraviolet light kills bacteria and sterilises the water.
And because it all happens quickly, the water doesn't have much chance to cool. Each "loop" of recycled hot water only need to be heated a couple of degrees.
After each shower, the filters can be programmed to automatically clean themselves.
The designers report a 90% reduction in water usage, and 70-90% less energy, for a 10-minute shower dumping 10 litres per minute. They envision a future where all household water use is linked and recycled, including the dishwasher, hydroponic garden and toilet, to dramatically reduce consumption.
The Showerloop design team plans to have a kit on sale this month for €1,500, which includes filters and showerhead, but there is an issue for some: the water-collection part of the Showerloop must be placed below the shower floor. Some installers may need to rip up their bathroom, but the designers say they're working on ways to get around that.
If you're feeling particularly handy or can't wait for the kit, they've also made the plans open source. Anyone can download them – all they ask is you let them know how you go.
And the guilty shower could be a thing of the past.
Belinda Smith is a science and technology journalist in Melbourne, Australia.
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.