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Reasons to avoid low-flow shower heads and pick the better alternative - Smart water saving shower

Updated: Jan 15




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As a significant part of the country is experiencing drought conditions, many of us are probably considering switching to a water-saving shower head or a low-flow shower head to combat the increasing water and energy price and also help the environment. Interestingly, when you look for a solution to this the internet and government or even local water districts recommend low-flow shower heads as a basic solution. However, the devils are in the details.


Those who have tried them know that it is a compromised solution, no more strong, heavy rainfall or waterfall sensation, no more immersive water coverage like the big shower heads, and quite surprisingly, it might not actually save that much water.


Yes, you read that correctly. Standard low-flow showers tend to not save as much water and energy as promised. Let’s take a deep dive into low-flow shower heads, and learn why we created a better alternative, the Oasense Reva smart sensor shower head, to help you preserve the best part of the shower experience while saving more water effortlessly.


What is a low-flow shower head?


A low-flow shower head is commonly regarded as a shower head that has flow rates lower than 1.5 gpm. The standard way to measure shower head flow rate is to measure at 80 psi in coming pressure so we can compare between different brands and models.




How to choose a low-flow shower head:


Well, if you ask us, the answer is easy. Don't even think about it. Pick the Oasense Reva instead, here’s why:






What are the common myths about low-flow shower heads?


We will address some of the common beliefs here in detail and why they are not true.

  1. low-flow shower heads work as intended to save water

  2. low-flow shower heads provide a good shower experience

Let's look into it:


A. How much water does a low-flow shower head save?


Answer: Not as much as commonly believed.


Almost every low-flow shower head claims to save water, but is it really that simple? You probably have seen a demo like this:


  • Two fish tanks and a timer

  • One shower head with 2.5 gpm flow rate, another one with 1.2 gpm flow rate.

  • Point both shower heads to a fish tank respectively, start the water and the timer, timed for 5 mins.

  • Surprise surprise! The 1.2 gpm shower head only fills up half of the fish tank whereas the 2.5 gpm shower head fills it up!

  • You just saved 50% of the water! Congratulations!


This type of tautological demonstration is everywhere, you see them on YouTube, on blog posts, and in commercials. But does that hold true? In fact, this is a misleading simulation of the real situation and not quite the journey you will have while using one.


Of course, when you use a fixed timer and time different GPM ratings, you will get different amounts of water coming out. That is the definition of “gallon per mins”, however, does gallon per min translate directly to water saving? If I use a 0.1 GPM shower head for the shower, do I save 96% of my shower water? See the caveat of this? It is not possible to just cut the water in half and claim all water saved because when the water flow is restricted, showers time changed and often become longer. You probably need to shower 100x longer with a 0.1 GPM shower head to get the same cleanliness compared to a 2.5 GPM shower head if the 0.1 GPM flow rate is really shower-able. This is just one of the reasons why we think that low flow is not the answer to our water problem, as a reduction in flow only encourages longer showering times in order to achieve the desired rinsing amount.


Why low flow (low GPM) does not mean lower water usage and energy saving?


There are two main factors for this, one being, facilities and secondly, human behavior.


1. Warm-up efficiency is bad for low-flow shower heads.

Those who have made the switch from a higher flow to a low-flow shower head may know what the problem is here. You installed a new lower flow shower head and waited 5 or even 10 more minutes just to purge out the cold water. Well, it is definitely not your plumbing, it’s the shower head. This is sadly a reality for low-flow showers as they take longer to pull the hot water from your tank and it consumes more energy and water than you think.


In plumbing systems, when we restrict the output flow rate, we not only elongated the time where hot water travels through cold pipes to reach the shower head, but we also introduced more chances of turbulent flow in the pipe where more cold water is mixed with hot water instead of being pushed out by that latter. This results in a lower overall temperature, more heat loss to the ambient temperature due to the prolonged amount of time that the water has stayed in the pipe, which leads to a much longer warm-up time.


We can not quote enough of the detailed study done by Evolve which makes thermal shut-off valves for hot water reservations. The effect of limiting the flow rate to a longer warm-up time is not linear, but exponential. We are waiting more than six times longer for hot water compared to the pre-1992 era. And if we further limit the flow rate to the low-flow regime, then the wait time would be a lot worse. The study has also shown that warm-up water waste consists of up to 30% of the water shower waste on average, that’s the data with all flow rates blended together. If we look at low flow only, the warm-up waste would be a lot worse. And keep in mind, that shower water is “hot water”, and water has great heat capacity. Wasting heated water is wasting both energy and water.


To counter this problem, we recommend that you either don’t use a low flow shower head, and use TSVs like evolve or automatic TSV’s like the one embedded in the Oasense Reva, and maybe add the recirculation pump so you have instant hot water. Yet the recirculation pump uses a lot of electricity so the net might not be a worthwhile investment.


2. Rinse efficiency is bad for low-flow shower heads which means you have to rinse for longer

We use soap and shampoo to cleanse our hair and skin. The van der Waals forces of these surfactants will grab oil and water at the same time. This means that we have to use water to make sure we can remove them from our skin after we apply them. The total amount of water we need to rinse off the same amount of soap you use is more or less the same. If you over-soap your hand, you would have to rinse longer, same with your body. Reducing the water flow will only elongate this process, while it’s not necessarily proportional to the flow rate of a shower or faucet, it is for sure that if you use a 1 GPM low flow shower head, you will shower longer time compared to a 1.8 GPM shower head.


It's a fact of life that when we get covered in mud, the salt water from the beach, sand, shampoo, and product, we really do need a substantial amount of water to rinse off. Restricting the water too much, as the low-flow shower heads do, will inevitably make the shower longer.



B. Low flow shower head can provide high pressure.


This is a rather tricky topic to touch on. But we can arguably answer this by considering a few factors:


  1. Yes, low-flow shower heads can have high pressure with some drawbacks.

  2. High-pressure low-flow shower heads are not the most pleasant shower experience.


When we think of high-pressure showers, typically what comes to mind is the strong massaging, steamy and full water coverage, and any other scenario you can think of as a good showering experience. A high-pressure low-flow shower head simply cannot deliver on all of those goals. In order to squeeze the remaining pressure out of the low flow rate, the design has to have a very limited water coverage, and a very pointy or misty water stream so you can feel like the pressure is strong.


Pressure alone can be somewhat boosted, but it would still not be as good as a higher flow rate shower. A higher flow rate can give you more variety of spray patterns because they have enough water to do so, and have an even higher jet mode if they apply a similar design to low flow shower head nozzles, or have similar pressure of low flow shower head but wider coverage. The flow can also be gentle, heavy, and fulfilling which you can’t get from low flow shower heads.


Most importantly, the flow rate is one of the most crucial components of shower pressure. If you have no flow, you have no pressure. With higher flow rates, you can go high or gentle. And with a higher flow rate, you can always have higher pressure than a low flow shower.


Take a look at the google trend of “high pressure shower head” and “shower gpm” in the last 10 years. The search trend in google is not a coincidence. As more and more regions started to restrict shower head gpms, the more people needed to search for “high pressure shower head” guess what, because the lower the gpm, the lower the pressure, you get a reduction in the shower experience.



A 2.5 gpm shower head will have a better pressure and shower experience than a 1.5 gpm shower head. A 1.8 gpm shower head would have a better pressure and shower experience than a 1.0 gpm shower head.


Another drawback of low flow shower heads boosting the pressure is the temperature instability. To boost pressure, shower heads are forced to use tiny orifices, and once they are below a certain threshold, the water droplets come out of the shower to become super small, almost misty, these water droplets have a lot of surface area to contact with cold air, and hence the temperature cools down super fast.


Take this “Rehave” shower made for about $1 from Alibaba for example, if you take the shower head away from the body 4 inches more, you will feel a sudden temperature drop. It would be very annoying to actually use them. In some cases, you would have to set the hot water temperature, whether it's a tank or an on-demand heater, to be at a higher temperature. This again upsets the energy saving that low-flow shower heads are meant to do.


To sum up the first part, we know that low-flow shower heads don't necessarily save water, because of the prolonged warm-up time and a longer shower time, and in some cases even work against water and energy savings. Moreover, they don’t provide good showering experiences and pressure as a normal flow shower head.


So what can we do if we want to have a good shower and still save water at the same time? The answer is to switch to Oasense Reva smart shower head.


The best water-saving shower head - Oasense Reva



Reva is a sensor-embedded shower head that is not only WaterSense certified but more importantly uses the shower water in the most efficient way. It has the maximum flow rate yet it can act like a 1 GPM shower head effectively. It has an embedded sensor that pauses main water flow when water is not needed and gives you full pressure of water during rinsing, it’s the most efficient way to save water and still enjoy rinsing.


Here are 3 reasons for you to consider buying an Oasense Reva as a water-saving shower head over a low-flow shower head.


1. Superior shower experience, high water pressure, and temperature stability.


With the higher flow rate, high-pressure nozzle design, and 6” rain shower-like coverage, Reva provides you the traditional fall rinsing experience like an immersive rain. Contrary to the “nozzle tip” and “pressure engineering” limitation with low flow shower heads that leads to tiny head and pointy water coverage, Oasense Reva provides the best rinsing experience yet saves water effortlessly.




Temperature stability is also one key thing. With low flow shower heads, when they over-pressurized the water steam, it makes them misty because surface areas of the water droplets become so big as the water droplets become smaller and smaller. This causes it to lose temperature to the cold air rapidly, so if you step slightly away from the water stream the temperature changes, which is not great. With Reva this isn’t a consideration that you’d have to worry about, with on demand full pressure droplets at your exact temperature, every time you step forward under the sensor.


2. Superior water saving


Two key features make Reva a better water-saving tool than low flow shower head.


a. Eliminates warm-up waste.


Oasense’s smart thermal sensor uses a machine learning algorithm to detect your water setting at the tap. Once the water temperature reaches the settings, the flow will be reduced to only 15%.


There are two aspects that this feature saves a lot more water and energy than low flow shower heads.


i. The cold water purging efficiency is higher.

As mentioned in the previous part of this article. Warm up water wastes and flow rate relation is exponential. With 1.8 gpm or more, Oasense Reva purged out cold water faster, preserving the heated water in the pipe, you will wait less time to get cold water.

ii. The behavior wastes are eliminated with our automatic thermal shut-off feature.

What do you do while waiting for water to warm up? Check your email. Texting a friend, brushing your teeth? Behavioral wastes can take up to XXX percent of water wastes. Studies show that people waited on average 47 seconds after the water is warmed to shower. With low flow shower heads’ long wait time on hot water, you can’t just stay there and feel the water all the time. Reva’s sensor would come in greatly. Once the water is warmed, only 15% of the flow will remain, that’s less than low-flow shower heads. This is one of Reva’s most praised features, giving you a worry-free prep time before you step into the shower.


b. Eliminate non-rinsing wastes.


There are certain times, in fact, lots of time you don’t need running water, when we soap or shampoo, or scrub we actually don’t want water on the body. What does the water do? Most Americans just let the water run free. If you can run a Navy shower, congratulations, you are one of the environment heroes, but if you don’t often the water just goes straight down to the drain.


Oasense unique sensing technology solves this problem with style. Take one simple step back and the water flow is reduced to 15%, still keep you warm, but at the same time save the majority of the amount of water you don’t need.


By concentrating all the water towards rinsing and eliminating all the unneeded rinse, Reva gives you the high flow shower sensation yet saves water like a 1gpm shower head. Our average users save 50% or more compared to their old shower heads.


3. Quality and aesthetics



Low flow shower heads are generally cheaply made. While there are some reputable brands out there we don’t want to discredit them, but due to the design limitation and competition from Factory of China, we often get very little design and almost ugly look of the shower head. They also broke very fast, after all, some of them only cost less than $1 to build. Check them out on Alibaba, does your low-flow shower head show up?


Design is the core of Oasense. We derived Reva’s design concept from fashion trends, and nature, and distilled the elements to make our product. Every line, every curve, and every surface are carefully calculated to give you the best look for your bathroom. It is also constructed with full metal casing, frame grade poly-carbonate and high-quality space grade material at the core of the turbine to ensure reliability.


We want to provide the best water-saving experience with the best product and show the world that eco-product doesn’t mean compromised experience and product quality. And we did it. Oasense Reva has won 2 Reddot design awards, in the design category and its technology category.



To sum up, the best low-flow shower head is a high flow shower heads that saves water automatically -- Oasense Reva!




Enjoy your Oasense Reva now and get $35 off your first purchase. Avoid the crappy-made low-flow shower heads that don’t save you water or shower well. Shower better, save water better with Oasense. It is the best water-saving shower head on the market.



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