Often showers take 15 minutes or more while shaving or when especially sleepy. As a deterrent to being late and to conserve water I sometimes do the ultra-fast shower.
Ultra-fast shower: wet for 10 seconds at faucet, water off, then lather up everywhere, then shower on for a rinse. There are two drawbacks to this method which I hate: waiting for the water to heat up and that while lathering the air in the shower is cold.
Ideally, the air in the shower and the tile floor would both be around 100°F for comfort. A button would douse the user for ten seconds, then stop. After lathering or even shaving in the warm, moist air environment, a regular shower would rinse off in about 30s to a minute.
I want to apply this Ultra-fast pre-heated shower environment to existing shower installations, with dual tub/showers OR standalone shower stalls. I hope to change the way people think of getting clean, and reducing heated water consumption in showers by 85% or so, in my case.
Nice idea. Are you planning on heating the shower water locally? My shower runs water for 45 seconds before getting warm (a problem I'm trying to solve in my project). Also, for this project to be successful as an eco-friendly design you would have to prove that the energy used to heat the shower space was less damaging to the environment (and less costly) than the water that would have been wasted. I look forward to watching your project.
3.6 cubic meters in a shower stall (4 foot x 4 foot x 8 foot) requiring a temperature increase of 20C (20C -> 40C) would take about 24Wh of energy. Even assuming a few cycles (air moving in and out) it's going to be massively less energy than the approximately 500Wh per minute required to heat water being used continuously.
This sounds great for RVs, campgrounds, "off the grid" buildings, anyplace where water and energy are at a premium.