The cost is more than the box
Two units with the same purchase price can have very different lifetime costs. The installed cost includes the equipment, labour, the gas permit and any plumbing permit, and on a conversion it adds venting, gas supply work, a condensate path and electrical work. Those are separate from the unit and are itemized separately in a written estimate.
After installation, the recurring costs are energy, maintenance, and eventual repair or replacement. The equipment price is the smallest and most comparable part; the rest depends on the site and how the unit is used.
Energy is the biggest variable
FortisBC states that 26 per cent of a home's energy use goes toward water heating, which makes it one of the largest single loads in a house. How much a specific water heater uses depends on the draw pattern, the set temperature, the inlet water temperature, the standby losses of a storage tank, and whether recirculation is running.
Efficiency is measured as Uniform Energy Factor (UEF), but a UEF value is only comparable with another value at the same draw pattern. The Bradford White RG240T6N's UEF 0.64 is a medium-draw storage rating; a condensing tankless unit's 0.95 is a high-draw rating. The direction is real, but the two are not a savings percentage, and this site publishes no savings claims.
Maintenance and descaling
Maintenance is a real lifetime cost and, on tankless units, a warranty condition. Rinnai states that lime damage is not covered by warranty and that hard water needs more frequent flushing, and it makes annual descaling part of keeping the heat-exchanger warranty. A storage tank instead needs its sacrificial anode inspected, the T&P relief valve exercised, and sediment drained, per the manufacturer's manual.
Skipping that maintenance does not save money; it moves the cost to a repair or an early replacement. The maintenance schedule guide sets out the intervals for each type.
Repairs and expected life
Repairs accumulate differently by type. A storage tank's common repairs are a thermocouple or thermopile, a thermostat or high-limit, or a relief valve, and its tank body eventually fails and is not repairable. A tankless unit's common issues are scale, a fouled inlet filter, a blocked condensate trap, or an ignition or flame-sensor fault, and its heat exchanger can last longer than a tank with proper flushing.
FortisBC states that tankless water heaters have a 20-year life expectancy, almost twice as long as storage tank models. Longer life spreads the installed cost over more years, but it also means more years of maintenance, so both sides of the ledger have to be counted.
Why no savings numbers here
Savings percentages and dollar figures depend on the fuel rate, the household's usage, the set temperature and the installation, none of which this site can know for a given home. Publishing a number would mean inventing one. Instead, the estimator gives a CAD ballpark for the work with the conversion allowances shown separately, and a written estimate follows the assessment.
CANRO Heating & Cooling provides free written estimates for replacements and installations, and the assessment measures demand and site conditions before a model or a path is recommended. The decision is made on the home's numbers, not a generic payback claim.