Question: What is the best way to make it easier for a family of four to take back to back showers?  1. Install a larger water heater.  2. Make your teenage daughter live elsewhere.  3. Install a thermostatic mixing valve. 4. Any or all of the above.  No, the answer does not necessarily HAVE to be #2!  The answer probably is #4, although we don’t recommend relocating family members.  The answer is both 1 and 3, and there are a few variables which will determine which one would be best for you.  The most costly solution would be to simply replace your water heater.  Of course, this would only make sense if it were fairly old (over 8-10 years in most cases).   There is however a less costly alternative to replacing the entire tank, and that would be to install a thermostatic mixing valve and turning up the temperature on the water heater.  By doing this, you are increasing the BTU’s, or stored energy,  inside of the tank and you are actually “stretching” the capacity of the heater.  Yes, it is still the same volume, but it now requires less hot water from the tank to get to the temperature you desire at the taps.  While it is possible to simply turn the water heater up without a mixing valve, this is a very dangerous practice, and is never advised.  The risk can present itself very severely, especially if you have an older home without pressure balanced shower valves.  Second and third degree burns are a very real possibility.  A thermostatic mixing valve (TMV) has an inlet for the hot water, an inlet for the cold water and a mixed outlet.  Installing this device is a MUST if you are ever to turn your water heater above 120 degrees.  The mixing valve will prevent the higher temperature water stored inside of the tank from ever reaching the taps, and your skin.   

Although this topic is focused on increasing the capacity of your water heater for enjoyment purposes, there is however another, more important reason for doing so.   Legionairres disease is mistakenly thought to be uncommon.  This is mainly because of misdiagnosis’ and unreported cases.  Many times the disease only strikes a few at a time, and rarely get the publicity of other ailments that sicken many at a time.   Legionairres disease is caused by the strain of bacteria known as legionella.  Legionella breeds very aggressively in stagnant water temperatures between 95 and 115.  This means if your water heater is only set to 115-120, it will be well within the breeding range most of the time as the temperature dips 10-20 degrees until the heater “calls” for more heat.  Installing a thermostatic mixing valve and turning up your tanks temp above 140 degrees will help keep your family safe, and in the shower longer!    

This is a relatively simple job for an experienced plumber, and will definitely be money well spent. 

Kohler K-13601 Thermostatic Mixing Valve – To purchase click on the image above.
You can count on this thermostatic mixing valve and all Kohler supplies to keep your fixtures at optimal performance. The valve mixes hot and cold water to allow for a wide range of temperature selections or fixed settings. Solid brass construction ensures years of reliable use. Kohler K-13601 Thermostatic Mixing Valve Features: Solid brass construction ensures years of reliable service Mixes hot and cold water allowing for a wide range of temperature selections or fixed settings Kohler Lifetime Limited Warranty.