Converting from a gas storage tank to tankless involves a gas line and venting assessment, then a full-day installation and adjustment period.
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Quick answer
Converting from a gas storage tank water heater to a tankless unit starts with an assessment of your gas line capacity and available venting routes, since tankless units generally need more gas flow and different venting than a tank. Installation typically takes most of a day, involving removal of the old tank, running new venting, and connecting the tankless unit, followed by testing. As a ballpark, not a quote, tankless installs commonly run $3,500 to $7,500 depending on what the assessment finds.
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A tankless unit draws gas at a higher rate than a storage tank during active use, so the first real question in a conversion is whether your existing gas line can supply that demand or needs to be upsized. The second question is venting: tankless units typically vent differently than tank-style units, often requiring dedicated venting run to an exterior wall rather than sharing an existing chimney. Both of these are assessed before a firm quote is given, since they're the two factors most likely to affect cost and the scope of work involved.
In many Metro Vancouver homes, especially older ones, this assessment also considers where the tankless unit will be mounted, since it's wall-mounted rather than floor-standing, which can free up space in a mechanical closet but requires a wall with adequate clearance and access for future service.
Most conversions are completed in a single day, though homes with more involved venting routes or gas line upsizing can take longer, which should be discussed during the assessment rather than as a surprise on installation day.
A tankless unit delivers hot water on demand rather than from stored reserve, which means no more running out of hot water during back-to-back showers, but it also means a very small delay at the tap while the unit ramps up, which some homeowners notice at first and adjust to quickly. Households with a laneway home or secondary suite drawing from the same system often see the biggest practical benefit, since a tankless unit's continuous supply better matches higher combined demand than a fixed tank ever could.
| Aspect | Storage tank | Tankless |
|---|---|---|
| Hot water supply | Limited by tank size, can run out | Continuous, limited only by flow rate |
| Space | Floor space in mechanical room | Wall-mounted, frees floor space |
| Maintenance | Occasional tank flushing | Periodic descaling recommended |
| Ballpark install cost | Depends on size, vent type, access | Commonly $3,500–$7,500, not a quote |
Give the household a few days to adjust to the on-demand nature of a tankless system, and ask your installer about the recommended maintenance schedule, since periodic descaling helps the unit maintain efficiency over its life. Keep the installation invoice and any warranty registration confirmation as part of your system's ongoing record.
Because a conversion typically means the household is without hot water for the duration of the visit, it helps to plan the day around that, particularly if young children or a busy household routine make timing matter. Ask your installer for a realistic estimate of the day's length based on what the assessment found, so you can plan showers, laundry, or other hot water needs around the work rather than being caught off guard partway through the day.
Safety note
Converting to a tankless gas water heater involves gas line and venting work that must be completed by a Technical Safety BC licensed gas fitter; CANRO holds gas licence LGA0043870. If you ever smell gas, leave the home and call FortisBC at 1-800-663-9911.
Most conversions are completed in a single day, though homes needing gas line upsizing or a more involved venting route can take longer.
No, a properly sized tankless unit provides continuous hot water, limited by its flow rate rather than a stored reserve.
Sometimes; it depends on your existing line's capacity and the unit's peak demand, which is confirmed during the assessment.
It generally benefits from more regular attention, including periodic descaling, compared to occasional tank flushing on a storage unit.
Not always; it needs a wall with adequate clearance and a viable venting route to an exterior wall, which is confirmed during the assessment.
Often yes, since continuous supply better matches combined demand from multiple living spaces than a fixed tank size.
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