A sustainable home will be a smarter home, and you can start with the shower. The Oasense Reva smart showerhead is a self-powering water- and emissions-saving addition that turns down the water flow to only 0.27 gallons per minute (gpm) when you step back to soap up or shampoo and senses when you step under the water to rinse, turning the flow up to 1.8 gpm, the typical low-flow rate for water-saving showerheads.
The $350 Reva earned our Greener Shopping Difference Maker designation, which represents a product that reduces environmental impacts by 50% or more compared to comparable products. We tested the Reva for a month and found it reliably reduced water usage and water-heating CO2 emissions by about 51% compared to a standard low-flow showerhead, and by 64% compared to a traditional 2.5 gpm showerhead. It uses sensor technology to track whether one is standing under the shower, drawing power from the flowing water to power a motion sensor and display indicator LEDs. You can estimate your water, energy, and financial savings using Oasense’s calculator.
The Reva Experience
In an era of water shortages and rising water prices, the Reva makes good environmental and financial sense.
When running at full flow, the Reva is an attractive showerhead that delivers a steady rain-like shower from all the nozzles; at the low-flow setting, water streams from six central nozzles (see the image at the top of this article), enough to wet a washcloth or catch water in cupped hands to shampoo. We particularly liked the sensor’s ability to run the water at full flow until it is warm, then reduce to the lowest flow to signal the water is ready. No more testing the water temperature with your hand.
Installation was easy, requiring only a wrench. It should be placed so that the Oasense name is at the top of the showerhead, which positions the sensors at the bottom, where they can “see” you step into the flow. We found that the angle of the showerhead is critical to its proper function. If angled too much toward the floor when mounted on a wall, it does not consistently sense the person moving under the water — a wave of the hand at the bottom of the showerhead solved the problem. Oasense recommends maintaining a 10° to 25° angle unless the shower is installed vertically from the ceiling. The Reva features an easy-to-find and -click button that switches the full-flow setting on until it is clicked again or the shower ends.
Once installed and after several showers, the battery in the Reva remains charged for up to six months, according to the company. Because it generates power from the flowing water, it charges the battery each time it’s used and reportedly will last many years. Two of our trial users did complain that the water turbine that generates the electricity is noisy, and it does produce a whirring hum that can be heard through the plumbing in other rooms of the house. “It’s not perfect yet but we will keep improving it,” Oasense wrote. The Reva is a substantial improvement over more complex smart showers, some of which inexplicably depend on a phone app to control, and traditional plumbing. Its 10-year warranty also makes it a solid purchase that can be repaired if the electronics or flow-control mechanism fails.
While the product is expensive upfront at $350, like many sustainable products it provides long-term savings due to reduced consumption of water and natural gas. For example, based on the local water and gas rates in our community, the Reva will save approximately $95 a year, offsetting the initial purchase price after four years.
Using the energy generated from water pressure is an example of looking at the existing built environment to find wasted resources that can be used to improve sustainability. It makes sense to draw on water-borne energy to power plumbing fixtures, and we expect smart, self-powered sensors will be widely adopted in other bathroom fixtures (a faucet that stops when you remove your hands from the flow, for example), the kitchen, and around the house. NoOutage.com estimates that a 1.2-inch long water generator running at 1.8 gpm with 50% efficiency can be harnessed to generate up to 19 watts of energy an hour, far more than needed to power the Reva.
Product carbon footprint: Oasense tells us that their analysis shows the embodied carbon — the emissions associated with the raw materials and manufacturing — in Reva is about 50.7 pounds. The Reva is manufactured at Taiwanese factories that use renewable energy for 15% of their power needs, so there is room for improvement as more solar is installed.
Shipping from the factory to a home in the Midwest will generate about 2.9 pounds of CO2, according to the Freightos Emissions Calculator, which is quickly offset by the reduced water heating CO2 emissions that result from using the Reva. Based on the amount of CO2 produced during manufacturing, we estimate that the full carbon footprint of making and shipping the Reva showerhead will be saved over the first 75 showers after replacing a low-flow fixture, or just 43 showers when converting from a traditional showerhead. For a family of four showering once every other day, the Reva should become carbon positive in less than a month.
Recyclability: From a practical recycling system perspective, it is not clear what recycling category it falls in, and we are not confident it will be accepted by any recycling programs in the U.S. without education about its construction for the companies that might disassemble and recycle it. The Reva showerhead is a complex device that includes metal, a thermoplastic polymer that blends rubber and polypropylene which requires specialized processing (by, among others, Reclaim Plastics), and electronic components that can be separated for individual recycling.
Oasense does not have a mail-in recycling program at this time, and we suggest they consider providing one to, at minimum, recapture the materials for processing after they are separated. “We designed this to last for 10 years,” Ted Li, the company’s co-founder said. “I promise you if we do last for 10 more years as a company I’ll definitely have a program to recycle our showerheads.”
Packaging: Reva packaging is largely recyclable cardboard, except for a plastic bag that contains the showerhead. We recommend Oasense remove the bag to make its packaging fully recyclable.
Oasense is a relatively new startup based in Mountain View, California. They support various ocean restoration programs, including coral and kelp forest repopulation projects by CoralGuardian.org and Sea-Trees, respectively. The team demonstrated an open, engaged relationship with us during our research.
The $350 Oasense Reva showerhead offers a six-inch rain shower face with sensors powered by a turbine that is driven by the shower water flow. Oasense provides free shipping and a 10-year warranty with a 60-day return policy.