Apparently Consumer Reports Turns Tattletale when they discovered one of their reviewed shower heads had more than the EPA mandated water flow (2.5 gallons per minute).
Since the EPA is planning to reduce flow even more I took a quick look through their report and found a couple of interesting things.
While they can’t really figure out a way to measure drop temperature per meter, there is a reasonable argument that more efficient shower heads make people use more hot water. That is, manufactures inject air into the stream to keep the pressure up. The air then cools of the water faster. Solution? Turn up the hot water and just let your heater and shower head fight it out. That sounds efficient.
Also, more concretely, more efficient shower heads increase the danger of scalding because the less water you use, the more dramatic the temperature difference when your roommate flushes the toilet!
If this happens, I’ll seriously consider just not using a shower head and let the faucet flow free.