Aquanta first came to our attention way back in 2014 with a very simple but very clever idea: a device that controls your water heater so it produces hot water only when you need it, instead of keeping 40 or 50 gallons of water hot 24/7. Since then, Aquanta has mostly worked with public utilities to get its product into homes. The company is now selling its controller direct to consumers, and after spending some quality time with a review unit, I think it’s a strong value.

According to the U.S. Department of Energy, heating water accounts for about 18 percent of a home’s energy consumption. That makes it the second-largest contributor to your energy-related utility bill (after heating and cooling), at a cost to the average family of $400 to $600 every year. You can think of a conventional tank water heater as a big thermos. It heats up 40 or 50 gallons of water and strives to keep all that water hot so that it’s available any time you need it. But if you’re like most people, you probably need lots of hot water only a few times a day: in the morning for a shower, in the evening to wash dishes, and maybe just a couple of times each week to run your dishwasher and wash your clothes.

One solution would be to replace your conventional tank water heater with a tankless model that heats water on demand. The Energy Department estimates that those appliances are two to three times more efficient than a tank water heater. But not only are they expensive, you’ll probably need both a professional electrician and a professional plumber to install one. What’s more, the agency says you might not recoup the purchase and installation cost via lower utility bills before the unit wears out and needs to be replaced.

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Four control options

An Aquanta controller costs $149 and you can install it yourself in about 20 minutes. There are models for both electric and natural-gas/propane water heaters, but there is no plumbing involved. The device offers four ways of controlling your water heater, balancing your desire for hot water with saving energy. Aquanta Intelligence, the default choice, relies on an algorithm that analyzes your hot water consumption and automatically turns the water heater on and off accordingly. You can choose from three models here: Less Efficient, Efficient, and Most Efficient.

The second option is best for people who follow a strictly regimented schedule: You can set timers that will turn the water heater on and off at specified times. This option is similar to the pre-Nest-era programable HVAC thermostats in that it lets you create one schedule for every day of the week; one schedule for weekdays and another for weekends; or one schedule for weekdays, a second for Saturdays, and a third for Sundays).

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The third option is for electric water heater owners whose utility offers a “time of day” rate that makes electricity more expensive during times of peak demand and cheaper during off-peak hours. Just select your specific utility from a drop-down menu. This will fire up your water heater only when energy costs are lower.

Finally, a thermostat control option keeps your water at a defined temperature. This is obviously the least efficient method, and it can’t raise the temperature beyond the tank’s mechanical set point anyway, but if you’re super picky about water temperature, the option is there.

Michael Brown / IDG

If you want to save even more energy, and you can remember to do it, you can tap an Away button in the app to tell the controller to turn the water heater off because you won’t be home to need hot water. You can choose either a Now setting or specify a future time that you’ll be gone, and then indicate the time the Away period should end and water heating should resume.