Low Flow Shower Heads Increase Hot Water Waits

3 min read

Low Flow Shower Heads Increase Hot Water Waits

The Conundrum

Bathers Don't Like Low-Flow Shower Heads & They Make Waits Worse

Low-flow shower heads save water and energy by changing the showering experience - usually resulting in weaker spray pressures and reduced body coverage. We know, as soon as we get in, that something's not right. It just doesn't feel as good and we're a tad colder.

Ask anyone if they want to take a low-flow shower and the response is typically a resounding, "No!".  In truth, we like, check that, love our shower's. And while we'd like to save water (and the energy used to heat it), using a low-flow shower head is often a bridge (er, sacrifice) too far. 

We're fond of our hot water too. It cleans and comforts us. But waiting for it to arrive is an inconvenient to say the least. Ask anyone if they like waiting around for hot water. You'll receive a disgruntled reply.

And that's the thing about low flow shower heads - they not only change how we feel in the shower, they change how we feel outside of it too. 

The math seems pretty simple. Cut a shower head's flow in half and it takes twice as long for hot water to arrive. For example, if it took one minute for hot water to arrive with a 3 gpm shower head, it takes two minutes with a 1.5 gpm shower head. Make's sense, right? Ah, but the impact is actually much worse than we think. 


More Waste Than What's In The Pipe

You Have To Purge 50% - 100% More Cold Water Before Hot Water Arrives

How could waits be even worse? Well, it's all about the physics of how hot water moves through the plumbing line as it travels from the water heater to your shower. The lower the shower head flow rate, the greater the hot water's thermal losses during its initial journey. 

Today's shower mixing valves blend hot and cold water to create your desired shower temperature. As a result, hot water line flow rates are 20% - 40% lower than shower head flow rates. With low-flow shower heads installed, hot water line velocities can frequently drop below 1 gpm - causing the hot water to slide up over the cold water as it travels to the shower head.

As seen in the illustration below, significant thermal losses occur when the Hot Slides Up Over Cold. The volume of water that must be purged before bathing temperature arrives is now 50% - 100% more than it was before the low-flow shower head was installed. 


A 6x Increase In Hot Water Wait Times

Yesterday's 30 Second Waits Are 3 Minutes Today

The impact low-flow shower heads have on how water waits, and the resulting water and energy waste can be profound. As as shower head flow rates are increasingly lowered, waits and waste become exponentially worse. 

Waits that were 30 seconds in the 1990's can be 3 minutes today - and the only thing that's changed in the the home is the installation of a low flow shower head. 


Hot Water In Seconds & A Shower You'll Enjoy

Experience The Difference With Evolve's Auto Diverting Tub Spout System 

Imagine hot water arriving in mere seconds and water saving shower you'll love.  It's possible. And, all it takes is replacing your tub spout and shower head with Evolve's Auto Diverting Tub Spout System (ADTS).




  • Hot Water Arrives In Seconds
    gets your shower warm in seconds. No more waiting, waiting, waiting for hot water to arrive. 
    • Freedom While You Wait
      Mornings are better when you don't have to choose between wasting your time or wasting your hot water. Now you can brush your teeth, shave or pick out the perfect outfit ... and your shower will wait for you.
    • Automatically Sends Hot Water To Shower Head
      No need to pull the tub spout's diverter to send water to the shower head. The ADTS automatically diverts when bathing temperature water arrives. It also keeps your shower water warm and waiting (no hot water waste) until you're ready to get in.

    • Eliminate Tub Spout Leaks
      The ADTS innovative design thermostatically seals to prevent tub spout diverter leaks while your showering. This nifty feature can save nearly 5 gallons of hot water per shower. 

    • High Pressure, High Comfort Showering

      Because its shower head delivers a clean, powerful and comfortable spray regardless of your home's water pressure, it's sure to have you singing in the rain.

    Learn More About The Auto Diverting Tub Spout System


      Contact Us

      Contact us today to learn more about how Evolve Technologies' products can bring comfort and convenience to your shower while lowering your residence's water and energy bills.


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