Tankless vs. Tank Water Heater: Which Costs Less in Canada?

A like-for-like gas tank swap typically runs $2,500 installed, while a tankless gas unit typically costs $4,750 once the extra venting is included. Tankless costs more upfront, but it lasts longer and uses less fuel, so the "cheaper" choice depends on how long you plan to stay in the house and what your current setup can support.

What drives the price gap

The unit itself is only part of the bill. We build our water heater estimates from labour hours × local trade rates plus materials, then check the result against market quotes, and the changeover type moves the number more than the unit does:

• Same type, same spot (gas tank to gas tank, electric to electric) is the cheapest changeover — the existing gas line, vent or circuit is reused.
• Switching to tankless gas usually means a condensing unit needs new PVC venting and a condensate drain, since it can't reuse a standard tank's vent. That's a real cost add-on, not a rounding error.
• Switching to electric (including a heat pump water heater) often needs a new dedicated circuit, and sometimes a panel upgrade if the existing panel is already full.

Here's how the main types compare on our model, before GST/HST:

Material	Typical	Usual range	Lifespan
Electric tank, 40-50 gal	$1,950	$1,500 – $2,500	10-15 years
Gas tank, 40-50 gal	$2,500	$1,950 – $3,200	8-12 years
Tankless gas (condensing)	$4,750	$3,700 – $6,200	15-20 years
Heat pump (hybrid) water heater, 50 gal	$5,750	$4,500 – $7,500	12-15 years

Tankless: the real cost isn't the unit

A tankless gas water heater typically prices out around $4,750, against $2,500 for a standard 40–50 gallon tank. The gap is bigger than the unit prices alone suggest, because most tankless installs in an existing gas-tank house trigger venting work: a condensing tankless unit vents with PVC, not the metal flue a tank uses, so you're paying for new pipe runs and a condensate drain even though the gas line itself is often reusable.

If your home is already set up for a condensing appliance — say you replaced the furnace with a high-efficiency model recently and the venting path exists — the tankless premium shrinks closer to just the equipment and labour difference. If it isn't, budget for that work rather than being surprised by it mid-job.

Heat pump water heaters: slower payback, lower running cost

A heat pump (hybrid) water heater typically costs $5,750, broadly similar to tankless gas, but almost always needs the "new circuit" changeover rather than "same," because it's an electric appliance going into a spot that likely had gas or a smaller electric circuit. It also wants some airflow around it to work efficiently — a cramped closet isn't ideal — so check the space before committing.

Where a heat pump water heater tends to make sense is a house that's already moving to electric heat, for instance alongside a Heat pump installation. Running both off electricity rather than mixing gas and electric systems can simplify the house's energy setup, even if the install bill is similar to tankless gas up front.

Lifespan is where tankless earns its keep

The table above shows the lifespan gap: a standard tank is usually the shortest-lived option, while tankless and heat pump units tend to run considerably longer. Spread over that longer life, the extra install cost of tankless looks smaller per year — but only if the unit actually reaches that lifespan, which depends on water hardness and whether it gets descaled. Hard water shortens a tankless unit's working life faster than it affects a tank, so in hard-water areas factor in occasional descaling cost, not just the install price.

The permit and licensed-trade cost that's easy to miss

Gas venting changes and new electrical circuits both need a licensed trade and usually a permit — that's true everywhere in Canada, not a quote padding. If a quote for a "simple" tankless swap has no venting line item and no permit mentioned, that's worth asking about directly, since it's one of the more common ways a tankless quote comes in artificially low and then grows once the installer is on site.

Which one to pick

• Staying in the house 15+ years, want lower running costs: tankless gas or a heat pump water heater, accepting the higher install cost.
• Selling within a few years, or the existing venting/circuit already fits: a standard tank is the lower-cost, lower-hassle choice.
• Already converting the house off gas: a heat pump water heater alongside a Furnace replacement or heat pump furnace keeps the systems consistent.

Whichever route you're quoted, our "is my quote fair" tool can check the number against local rates before you sign off, and the full Water heater replacement guide has size and access factors that move the price further.