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The rise of modern smart shower heads: overcoming the technological and power limitations

Updated: Sep 20, 2022

Take a look at the different types of smart shower heads, and smart shower systems on how they are evolved with the advancing power supplies, out of the shower head and inside them.

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Shower heads are dumb for too long

Showers or shower heads have not been generally associated with the word smart until recently. That’s pretty remarkable given that the first ever shower head was demonstrated way back in 1767 in London. That’s earlier than the first modern automobile, elevators, or even the first use of lightbulbs.

People’s lives have drastically changed since the 18th century. About 100 years later electric pumps were invented and people could open the tap and have pressured water, modern toilets sinks faucets, steward systems were implemented, and showering and bathing became a lot easier.

Fast forward to the 1950s, showering took over taking baths and it became the standard option for everyone for everyday washing and self-care. The number of shower heads sold suddenly sky-rocketed, however, the shower head pretty much stayed in its original form, a simple sprinkling device, despite other kitchen or bath utilities having all had significant upgrades over the years. We have automatic dishwashers, laundry machines, and all other upgrades of products with the addition of power.

In the 1980s, when the phrase “smart home” first became a buzzword, more and more home automation products were introduced. Things like motion-sensing lights, automatic garage door openers, programmable air-conditioning thermostats, home security systems, and wireless telephones were all revolutionary in those days.

After the first smart home wave, the second smart home wave revolutionized home utilities along with the concept of the “Internet of Things''. This was the introduction of smart doorbells, smart locks, smart refrigerators, vacuum robots, home cameras that connected to phones, and smart speakers that controlled your light or shades with a snap of a finger. All home appliances and furniture have received a full round of upgrades in the past decades. Shower heads have been improving as well, with additional spray modes, limited flow rates, and different colored showers every year.

The missing piece of smart showers — electricity

Perhaps the biggest reason that shower heads or shower devices are not able to have more functionality and enjoy some of these modern benefits of electronics is because of the limitation of power. It is not a surprise, after all, having electricity and water in close contact is a safety hazard. Almost no one puts power outlets into the shower stall or bathtubs where water splashes around easily. However, over the years, we do see glimpses of the development of a smarter, better, function-rich shower head. We will summarize this for you in the article as we look into the future of smarter bathrooms.

Here are some common sources of power for modern shower heads or shower systems today:

Plug-in power



Hydro-generation in a shower head

Heated shower head, electric shower, power shower

photo credit: By User:Chixoy - Own work, CC BY-SA 3.0,

There are some shower heads that you can plug in that heats up water instantly. The so-called power showers, electric showers, or the “suicide showers” show up in places where heating water tanks wasn’t popular or difficult to implement, quite common in older buildings in southern America. These showers have heating filaments embedded inside the showerhead, often a big resistor or inductor for heat generation. As water flows through these heated metal pieces, water is heated instantly for shower use. Whether it’s having a plug-in outlet next to the shower head, or routing electricity from far away from the shower head, it is a safety hazard to heat water instantly and It certainly has caused casualties over the years.

A slightly more advanced design comes from a company called Marey where the shower head is more considerately constructed with all wires and other vulnerable parts well sealed and requires installation by experts. This is an example of how instant heating can work safely and without concern for water splashing causing injury to the shower user.

Another common shortcoming of this type of electric shower is that the flow rate is limited. Water has a pretty high heat capacity, meaning that it takes quite some energy to heat up the water compared to heating up an aluminum pan. The specific heat of water is 4190 J/kg*°C, which means it takes 4190 Joules to heat 1kg of water by 1°C.

Assuming water commonly settles at 25°C, to increase the temperature to 40°C which is equal to 100 °F, the common shower temperature, the energy used is 104750 Joules per 1kg. The national shower head flow rate is 2.5 gallons per minute, which is 9.5 liters of water per minute. To have water instantly for a 2.5 gallons shower requires 995125 Joules, that’s a whopping amount of energy required. That’s why tankless heating often has a 30,000W rating (compared to 1,000 for a washing machine). So these tiny instant heaters would need to limit the water flow to avoid drawing too much current otherwise the power consumption would be safety-exceedingly high if a high flow instant heating shower head existed. That’s why even for Marey, the flow rate is limited to 1.5 gpm for this type of heated shower.

Smart shower systems

photo credit: Hansgrohe RainPad

Since it is dangerous to use a plug-in shower head, why don’t we hide them and protect them behind the wall when modeling the house? This is something that could be designed within the structures of a building or plumbed in before a bathroom remodel.

Without a power problem, kitchen and bathroom suppliers are more than capable of creating function-rich products, as the sensor technology to expand upon these kinds of smarter functions is readily available. For example, the touch-less sensor faucets we commonly see in airports or hotel lobbies were created more than 30 years ago. We can see more examples of complex and advanced technologies within our everyday appliances such as modern washing machines and dishwashers, so why wouldn’t this translate to other appliances in our home? Voice activations, LED screens, remotely turning on water, electric thermostatic valves for shower temperature controls, all of these features can be found in your smartphone or common appliances wouldn’t be hard if permanent access to electricity was possible. It's a fully digital experience of the shower system, and you can often use a digital shower control on the wall or maybe with your phone. One way to implement this is when new buildings are built, or when remodeling, these items should be installed into the walls by professionals to make sure that there are no safety issues.

One of the downsides of this approach is that it’s expensive and difficult to apply, which causes a lower volume for production resulting in higher cost, and it is also expensive to implement costing even fewer people willing to buy hence even lower demand. That is why these shower systems usually cost more than a thousand dollars and can add significant expense to install such a system with the added necessity of a plumber.

It seems that every major brand has a smart shower system offering, like Kohler, Moen, yet the adoption rate is not very high. Would you spend more than five thousand dollars on a voice-activated smart shower system?

So what else can we do without the need of a plug-in or remodel?

Perhaps a rechargeable battery?

One of the most recent shower innovations that are extremely popular, is the Bluetooth speaker shower head - The Moxie from Kohler. It is a waterproof speaker that fits into a shower head. Once it runs out of power, you can simply take it out and charge it for several hours, and then it’s ready to use again.

The reason that moxie is possible is that it is just like taking your waterproof smartphone into the shower and playing music. It is not part of the shower head, it is an add-on unit, and it doesn’t control anything on the shower itself, nor does it make any connection with the shower head electronically, so detaching and charging is not an issue.

Perhaps companies can take a page from Moxie’s book and have a detachable battery that can wirelessly charge the showerhead and can be recharged separately for a better water seal but to this day we haven’t found a product that works like that, and charging the showerhead every 2 weeks doesn’t seem very reasonable.

The ultimate power source for shower heads: the water

Water turbines for power generation purposes date back to the 1800s, with the use of water mills to grind corn being used centuries before that. With hundreds of years of turbine development, it is now possible for large-scale energy productions that produce megawatts of energy. At the same time, similar principles but miniature versions have emerged and companies have been integrating them into shower heads to power certain features. However, it is not like the wall mount where unlimited power is available. Depending on the design, the cost, maturity of the turbine, and the limitation of power vary. The power generation and the combination with a more efficient micro-electronic design can make these function-rich or “smart” shower heads retrofittable.

A Simple demonstration: LED shower heads

photo credit: Alibaba.

The most basic featured shower head is having an LED light. It would probably be exaggerated to call it a smart shower but it certainly is something different from the old boring units and the start of smarter shower dependents. There are lots of sizes and shapes of the shower head, and different LED colors, some can even blink or change patterns and don't require external power. The power electronics within these shower heads are quite simple, almost like a 9th grade project. Although these shower heads don’t seem to have much practical use, they are a decorative novelty that some shower users might enjoy.

Shower timers

With the LED shower heads maturing, adding features like a shower timer is a relatively simple next step. It serves the simple purpose as a time display, letting you know when the time of the shower is up by changing the LED color and hence be aware of the shower time and perhaps save some water during a shower.

You can find these types of shower heads cheaply and readily available on Amazon or Alibaba, or higher end, better finished Hydrao shower heads from Europe. The principle is quite simple, the longer you shower, the color turns red as a signal that excessive water is being used and it is time to turn off the tab and save some extra water.

Display, flow rate sensing and temperature sensing

Waterhawk came out as one of the smart showerheads in the 2020s. It actually featured a screen in the showerhead that displayed temperature and water usage in real-time with a screen, and it came with beautiful changing LED lights as an indicator of water temperature.

Although the company ceased to function, the craft of having hydro generators, computer screens, temperature detection, and flow detection was a great attempt to challenge the design of complex electronics into a tight package. Although some customers said it was not as reliable as they liked it to be. It is also understandable. To power a full screen, the turbine needs to be spinning at a relatively high speed to generate sufficient power, and hence it wears out quicker.


In the era of the internet of things, smart homes, and smart bathrooms, one would easily think that having a connection to your smartphone is a no-brainer. Although, knowing how much water you shower you used doesn't really require a smartphone app, and devices with connectivity doesn't necessarily mean it is smart and valuable. However, having a Bluetooth chip integrated into the shower head, with sufficient power to run it is still a huge step forward in smart shower technology exploration.

Both Hydrao and Hai showerheads send out Bluetooth connections to tell you how much water you used and are also retrofittable devices.

The positive of this kind of feedback is obviously knowing how much water you used, however, it doesn’t help you save water in real-time. To actually make a considerate effort to save water you would have to use self-discipline to actively reduce your shower time and perhaps examine your monthly bills before using such a shower head, to see if any significant savings have been made. And because we need the power to connect to the Bluetooth or WIFI in the shower head, one would need to have active running water so you can read how much water you used, which could be seen as contributing to needless water off.

Dawn of smart shower head, combining advanced sensors and multi-functionality

Evadrop was another major breakthrough in the field of smart showers concept. Although this crowd-funding water savor shower company never shipped out products. The concept, however, was very clever. A sensor was used to detect the proximity and adjust the water flow real-time. It is actually quite difficult to make sensing accurate and the complex internal plumbing system to work, therefore it’s not surprising that Evadrop was not able to ship out any products. Sensors need to see through all sorts of noise in the shower, like water splashes, streams, fogs, different lighting, different bathroom sizes. The showerhead sensor needs to be extremely adaptive to make it work.

The Oasense Reva

Another Kickstarter shower head that was founded in 2016 is Oasense. Oasense founders also created a proximity sensing concept that cuts off the water when the user takes a step back, an automatic shower. Despite the brilliant concept, Oasense wasn’t an overnight sensation. The original Kickstarter campaign didn’t pan out and the prototype sensor wasn’t working that well.

With strong community support after Oasense's viral run in 2017, our team kept the strong belief and continue the research and development. 5 years later our team of engineers finally brought to the market the most powerful smart shower head, the Oasense Reva. Reva has all the water-saving technology integrated into one elegant shower head, including a mini-AI powered sensor fusion suite that can detect, learn and adapt in real-time and sees through fog correctly, and solves all the problems that were previously mentioned. It also understands your thermostat choice, like an automatic thermal shut off valve (TSV) built in a shower head, so that whatever you set the temperature to be at the beginning of your shower, Reva will intuitively know when this has been achieved and limits the water once it has reached that point, and the waits for the user to step in before using full flow. Oasense Reva’s smart water-saving shower head gives you 100% full throttle spa-like water pressure with 6" luxury water coverage and saves more than 50% water with its special proximity sensing.

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Oasense Reva won the CES innovation award, and the Reddot design award and was nominated by Fast company as one of the world-changing ideas.

The secret of sensing lies not only in the advanced sensor design and machine learning algorithm but also in the specially engineered hydro-turbine. To power this complex sensor suite, the power source needs to be a higher wattage than ever before for a micro hydro turbine.

Think of smart devices as the human body. The most important organs are the heart which pumps the blood throughout the body and the brain which controls everything. In smart shower heads, the power generator of the shower head is like the heart, and the electronics, sensors, and microprocessors are like the brain. Without a powerful cardiology system, the brain cannot sustain at a high functioning level and would run out of oxygen and the shower head would die.

The Most efficient hydro generator on the market

Oasense Reva Embedded Hydro-turbine

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The Oasense team spent more than 2 years developing the highest efficiency hydro turbine at its form factor. The power generation is at least 10 times more than what is available on the market. The water inlet orifice size, the angle of the turbine fan, the strength of the magnet, the gauge of the coil, and power managing circuits were all carefully crafted to provide the best efficiency and wide range of incoming pressure and flow rate regulations from different regions. This efficient turbine spins up to 2000 RPMs and high-quality space-grade materials are used to construct the core of the turbine to ensure reliability. Thousands of hours of continuous stress tests were performed on these turbines before releasing them to the market.

The hydro turbine needs to be so efficient that it can generate sufficient power within the 3 minutes of shower rinse time to power the system. Our advanced turbine keeps turning and charging itself throughout the duration of your shower, even when the shower cuts to water-saving conditions, the design of the turbines continues faultlessly for the duration of your shower.

This is one of the key reasons why Oasense was able to bring in the most complex proximity sensing solution to shower heads in an all-in-one design concept where you can just install in seconds and never have to worry about charging.

What can we do next?

So far what smart shower heads can do are still pretty basic compared to a smartphone, a smart speaker or a smart dishwasher, or any other IoT devices. But things are about to change with Oasense’s powerful turbine. Connectivity and proximity sensing is just the basics. There are a lot more smart ideas in the Oasense pipeline to be announced.

Stay tuned.

Learn more about our technology here

Learn more about Oasense's design concept

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