This time of year the plumbing pipes can be cold in the morning. So it takes a while for the shower to warm up. I must admit that more than once, I've gotten distracted by shaving or getting my clothes ready while waiting for it to warm up. Coming back later to find steaming hot water going down the drain; water that I am paying for and paid to heat.
Well, here is a solution, evolve's ShowerSmart technology. I have blogged about more complicated solutions that require plumbing changes. This solution is nice since it just attaches in place of your existing showerhead.
Here is how it works. While the water is cold, it runs. Then when the water gets warm, it shuts down to a trickle. Now when you are ready, you can flip it on and step in to a warm shower.