Rinnai · brand guide

How long does a Rinnai water heater last?

Short answer: Rinnai is a tankless leader — 20+ years of life if you descale it, versus the 8–12 you'd get from a tank.

	Rinnai	Typical water heater
Typical lifespan	20+ yrs	8–12 yrs
Type	Tankless	Tank
Upkeep	Annual descale	Occasional flush

A Rinnai tankless unit can run 20 years or more — roughly double a tank — because there's no reservoir to corrode. The catch is maintenance: hard water scales the heat exchanger, so an annual (or with a softener, less frequent) descale is what actually gets you the long life.

Skip the descaling and you'll see error codes and falling output well before year 20. If yours is well cared for it may outlast the rest of the house's systems; if it's been ignored in a hard-water area, watch it more closely.

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The numbers above are model-specific; the full method — the warning signs, the costs, and when planned beats emergency — is in the when should you replace your water heater guide.

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