I was reading an excellent piece by Chris Mooney about how much water and energy is wasted by inefficiencies when people take showers, and I was struck by the sheer amount of waste:
So it's a triple-whammy of waste: Water and energy, and of course these cost money.
“Typically 20 percent of every shower, the duration, is essentially lost,” says Jonah Schein, technical coordinator for homes and buildings for the EPA’s WaterSense program. [...] Showering drives almost 17 percent of water use in homes, and an average American family uses some 40 gallons of water per day in the shower. This amounts to 1.2 trillion gallons of water in the United States each year, says EPA, “enough to supply the water needs of New York and New Jersey” over the same time period. If 20 percent of that is wasted, well, you’re talking about over 200 billion gallons, in a world where gigantic states (California) and megacities (Sao Paulo, Brazil) are suffering from drought and water scarcity problems are expected to become still worse in the decades ahead.
What’s more, because water coming out of shower heads is supposed to be hot water, showers are also energy hogs. They’re typically one of the largest drags on the hot water heater in the home, and water heating itself accounts for almost 17 percent of total home electricity, according to the Department of Energy.
The same part is that most of this waste is purely behavioral. People wait for the hot water to come (which can take a while if the water heater is far away), and so they let the water run. So far, that's a structural issue, and unless we can convince people to take cold showers (not such a bad idea), this won't change much. But the problem is that even after the hot water has come, people don't start taking a shower immediately. This looks like this:
Making people aware of this behavior can probably help, but it's very hard to change people's routine, especially when they don't perceive that there's a problem.
That's why I was so intrigued by a little piece of technology called a thermostatic shut-off valve.
Thermostatic valves are already used in fancy showers to regulate water temperature and make sure that the mix of hot and cold water stays constant, and that scalding is prevented if for some reason the cold water stops flowing. But a thermostatic shut-off valve does something different; it lets the water run until it reaches a certain temperature, and then it stops the flow until you re-open the valve.
The photo at the top of this article shows a standalone thermostatic shut-off valve, but you can also get it built in a shower-head like this:
You put it on the pipe before the shower-head (you already have a water-saving one, right?), and it automatically fixes the behavioral waste from showering without any inconvenient to you. You still get in a shower with hot water, all you have to do is reopen the valve. Problem solved!
Here's the simple installation process, as well as a demonstration:
It's so elegant that I think it should be made mandatory by the EPA. Think of how much energy and water (and money) this little gadget would save. Even if there's an upfront cost ($30 now, but I'm sure it could be a lot lower if produced in mass-quantities), over years and decades, savings would add up to large amounts, especially in drought-prone areas.
If you're interested, the standalone valve costs $30. The company estimates that it provides $75 yearly utility savings, 2,700 gallons yearly water savings, has a 4 months payback time, but take those numbers with a grain of salt (but even if it's 4x worse than that, it's still worth it!).
The version that is integrated into a fancy 1.5 gpm water-saving shower-head costs $40. For this one, the company estimates even bigger savings: $246 yearly utility savings, 8218 gallons yearly water savings, 2 months payback time. Again, your mileage may vary.
If this topic interests you and you want to dig deeper, there's actually a white paper on the topic of "shower warm-up waste."