“The design features of a conventional shower minimize thermal comfort, maximize energy use and water consumption while exacerbating moisture problems. Most of these negative effects are caused by evaporation. There is a simple solution to this; preventing airflow to and from the showing area is the key, in other words sealing the shower stall. Additional benefits can be obtained by the incorporation of insulated low thermal mass walls that heat up rapidly.”

“The result is a shower stall where air currents are minimized, humidity is increased and the air is warmer. All these effects will increase thermal comfort and reduce energy and water consumption. Another benefit is that with the air in the shower warmed, the water vapor present will not be condensing in the air, eliminating steamy conditions.”

“This energy efficient shower combines effectively with solar heating, since it allows for a fairly comfortable shower when water temperatures dip to 90ºF (Typical water temperature for a shower is 105ºF).”

Read more. Via Ask the Renewable Engineer. See also: The Shower Dome (and the DIY-version).