How long does a tankless water heater last, and how do you extend it?
Maintained lasts 20 years, left alone about 12. That gap is yours to keep.
A tankless water heater typically lasts about 12 to 20 years. Manufacturers rate them longer than a tank, but Florida hard water shortens them without annual descaling.
Pros who do this work near you
Local pros in St. Johns County who service tankless water heater. Free to browse.
Two lifespans
Florida's hard water scales the heat exchanger, and without annual descaling the unit fails early and can leak.
Overview
A tankless unit is more efficient and has no tank to rust through, which is why it can outlast a traditional water heater. The catch in Florida is scale. Skip the yearly descale and the heat exchanger starts to fail early, wiping out the lifespan advantage.
The maintenance that buys you the years
- Descale the heat exchangerHigh impactYearly, more often in hard water
Scale on the heat exchanger is what ends most tankless units early.
- Consider a water softener or pretreatmentHigh impactOnce
Cuts scale at the source, extending both the tankless unit and every other water appliance.
- Clean the inlet filter and air intakeMedium impactYearly
Restricted flow makes the unit work harder and short cycle.
- Flush per manufacturer instructionsMedium impactAs specified
Warranty and lifespan claims usually depend on documented maintenance.
Signs it is failing
- Hot water swings hot and cold mid-shower
- Reduced flow at the tap
- An error code on the display
- The unit runs longer to hit the same temperature
Repair or replace
Sensors, ignitors, and fans are usually worth replacing. A failed heat exchanger past 12 to 15 years usually means replace.
The facts
Florida hard water shortens tankless heaters without annual descaling. A softener or pretreatment upstream is the single best thing you can do for one here.
FAQ
About 12 to 20 years. It can beat a tank, but only if you descale it yearly in hard water.
Sources
Sources are general public references. Verify specifics for your model.
Make this one last longer
Book a pro who does this work, or add this tankless water heater to your free home record and get reminders when it needs service.
Keep going
Lifespans and maintenance guidance are general estimates and vary by product, use, and climate. Always follow your manufacturer's instructions.