A practical way to decide whether an aging Navien tankless water heater is worth another repair or ready for replacement.
Tell us what you need—we’ll call you back fast.
Quick answer
The decision usually turns on what's actually failing and how often it's happened: a clogged filter, worn igniter, or a single sensor fault is normal wear worth repairing, while a leaking or cracked heat exchanger, or a unit with a recent pattern of repeated faults, generally points toward replacement. Skipped annual maintenance is also worth factoring in, since a poorly maintained unit tends to fail earlier than a well-serviced one.
Need a licensed gas fitter for your tankless water heater? Call CANRO at (604) 359-1081 — residential natural-gas heating and hot water across Metro Vancouver since 1999.
Tankless units, like any appliance, have components that wear and get replaced over a normal service life: igniters, flow sensors, and inlet filters are all routine repair items and don't say much about the overall unit's health. A cracked or leaking heat exchanger is a different situation entirely, since that's typically the unit's most expensive internal component and a failure there usually isn't cost-effective to repair on an older unit. A licensed tech should clearly tell you which category your issue falls into.
A tankless unit that's had consistent annual descaling and service tends to hold up better and longer than one that's gone years without maintenance, particularly in homes on harder well water where mineral buildup accelerates wear. If your unit hasn't been serviced in a while and is now showing a problem, it's worth asking whether a proper descaling and inspection might resolve it before assuming the worst, since deferred maintenance is a common, fixable cause of declining performance.
| Situation | Typical recommendation |
|---|---|
| Clogged filter or minor sensor fault | Repair |
| Ignition or flow issue caught early | Repair |
| Cracked or leaking heat exchanger | Usually replace |
| Multiple failures in a short period | Replace |
| Unit never maintained, now underperforming | Service first; replace if damage is confirmed |
As a ballpark, not a quote, a full tankless replacement in this region generally runs $3,500–$7,500, while individual component repairs are typically a modest fraction of that. When repeated repair costs on an aging unit start adding up toward a meaningful share of replacement cost, that's usually the point to seriously consider replacing instead.
Sometimes a unit that seems to be failing repeatedly was actually undersized for the household's demand from the start, which shows up as chronic strain rather than a single clear fault. If that's the case, a straight repair or even a like-for-like replacement won't fix the underlying issue; the right fix is resizing the system to actual household demand, which a licensed tech can identify by reviewing usage patterns alongside the fault history.
Because replacement is a real investment, ask your technician to explain specifically what failed, whether it's a maintenance issue, a sizing issue, or genuine end-of-life wear, and why that leads to their recommendation. A straightforward explanation, rather than a vague push toward replacement, is what a proper diagnosis should sound like.
It's also reasonable to ask what a repair would realistically buy you in terms of extra service life, versus what a fresh installation offers in reliability and, on an older unit, potentially better efficiency. Weighing both sides with real numbers, not just a gut feeling, leads to a decision you can feel confident about either way.
Safety note
A tankless unit with a suspected heat exchanger leak, repeated ignition faults, or any sign of a gas or carbon monoxide issue should be shut down and inspected by a Technical Safety BC licensed gas fitter before being run again. If you ever smell gas, leave the home and call FortisBC at 1-800-663-9911.
Not always; it depends on where the leak is. A leak from a fitting or valve is often repairable, while a leak from a cracked heat exchanger usually points toward replacement, particularly on an older unit.
Yes, a unit that's gone years without descaling can show performance issues that a proper service visit resolves, so it's worth ruling this out before assuming the unit itself has failed.
There's no fixed number, but a pattern of multiple separate failures within a year or two is a strong signal that the unit is heading toward the point where repairs stop making financial sense.
It's possible, and chronic strain or repeated faults can sometimes trace back to original sizing rather than a component defect. A licensed tech can review your household's usage pattern to check this.
Not necessarily, if the existing venting is still code-compliant and in good condition, but a licensed tech should confirm this as part of the replacement rather than assuming it can simply be reused.
Family-run, TSBC-licensed (gas LGA0043870 · boiler LBP0046450), serving Metro Vancouver homes since 1999. Residential, natural gas only.
Call (604) 359-1081 Email info@canroheat.ca“Canro does an amazing job! Super professional and skilled with everything—boilers, furnaces, and AC. Always a pleasure working with them!”
“Five stars for Canro. We needed a replacement of a 30-year-old boiler. A new high-efficiency unit was installed—clean, professional work.”
“I can’t speak highly enough about George, who was recommended for a boiler service call for my parents’ home. George is excellent.”
25+ years keeping Metro Vancouver homes comfortable. Honest advice, upfront pricing, work that lasts.