What does tankless water heater installation cost in Toronto?

Hi, I'm Chris, and I'll guide you through this conversion. From your photo, you've got a conventional atmospheric-vent gas hot water tank in the basement. Moving to a high-efficiency tankless system is a great upgrade — endless hot water and reclaimed space — but it does take some physical changes. A tankless unit has different venting, gas, and power needs than your old tank, so the surrounding infrastructure has to be adapted.

Project Scope

Here's the full scope we'll work through, based on your request and photo:

1. Gas Tankless Water Heater Conversion:
   • Disconnecting, draining, and removing your existing gas tank.
   • Wall-mounting and plumbing a new gas tankless system (typically a high-efficiency Navien unit).
   • Upgrading the gas connection and running new dedicated PVC venting to the exterior.
   • Handling all required plumbing and gas-fitting permits and coordinating inspections.

Since this is a single multi-trade scope, let's go straight to the key decisions, specs, and site conditions needed to build you an accurate estimate.

To get started, please answer these questions:

Question: What is your postal code? (This lets us check local permit requirements, utility incentives, and pricing context.)

Question: Would you prefer the standard Navien tankless model (NPE-240S2) or the premium model (NPE-240A2), which adds a built-in buffer tank and recirculating pump to prevent cold-water 'sandwiches'and deliver hot water faster?

• Standard Navien (NPE-240S2)
• Premium Navien (NPE-240A2 with recirculation)

Question: Roughly what year was your home built?

• Pre-1990
• 1990 or newer

Question: Is there a standard 120V electrical outlet within 6 feet of the water heater? (Your existing tank uses no power, but a tankless unit needs electricity for its controls and ignition.)

• Yes, there is an outlet
• No, an outlet needs to be installed

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Photos that would help

To verify your venting path and gas-line compatibility, a couple more photos would help a lot:

• Exterior Vent Location: the outside wall nearest the water heater where the new exhaust and intake vents will exit.
• Gas Meter / Main Line: your gas meter or the main gas line entering the home (so we can see if your gas capacity is ready for a tankless unit).

Your project estimate

Project summary

The client wants to replace an atmospheric gas hot water tank in the basement with a contractor-supplied premium Navien NPE-240A2 tankless unit. The home is post-1990, a nearby 120V outlet is already available, and new direct venting will be core-drilled to the exterior. Gas and plumbing permits are required.

Estimate range

$5,000 - $7,600 This is a starting ballpark, not a final price.

Estimated work

Item	Details	Range
Navien NPE-240A2 Tankless Water Heater Installation Package	Install the contractor-supplied Navien NPE-240A2 premium condensing tankless unit on the basement wall. Covers connection to the existing water, gas, and 120V supply, routing of standard dual-pipe combustion venting, and system commissioning. Standard municipal permit fees, existing tank removal, and disposal are bundled into this package.	$4,600 - $7,100
Municipal Gas and Plumbing Permits	Prepare and administer the Gas Permit (TSSA) and Plumbing Permit (City of Toronto). Permit fees and admin costs are included in the main tankless package.	$0 - $0
Existing Tank Removal and Disposal	Demo, remove, and dispose of the existing atmospheric-vent gas tank. Disposal and hauling are included in the main tankless package.	$0 - $0
Thermal Expansion Tank Installation	Supply and install a thermal expansion tank on the cold water supply line to meet current Toronto plumbing code.	$200 - $350
Condensate Neutralizer Cartridge	Supply a condensate neutralizer cartridge to treat acidic condensate before floor-drain disposal. Install labour is included in the main tankless package.	$100 - $175

Cost summary

Category	Range
Materials	$5,000 - $7,600
Labour	$0 - $0
Total	$5,000 - $7,600

What is included

• Coordinate the plumbing and gas permits with the local authority (City of Toronto / TSSA).
• Shut off the water and gas supply; drain and disconnect the existing atmospheric gas tank.
• Remove and safely dispose of the old tank.
• Wall-mount the new Navien NPE-240A2 premium tankless unit in the basement.
• Run new dedicated water supply lines, shutoff valves, and a thermal expansion tank where local code requires.
• Core-drill the exterior wall (if needed) and route new dual-pipe PVC/CPVC combustion intake and exhaust vents outdoors.
• Connect the gas line to the unit, confirming pipe sizing (typically upsizing to 3/4" gas pipe if the existing is 1/2"), and run a gas leak pressure test.
• Install a condensate drain line with a neutralizer cartridge, routed safely to a nearby floor drain.
• Plug the unit into the existing 120V outlet, fill, purge air, test for gas leaks, and commission.
• Coordinate the final plumbing and gas inspections with municipal inspectors.

Permits or inspections

Item	Why it may be needed
Gas Permit	Required for installing a new gas-fired appliance and modifying gas piping in Ontario.
Plumbing Permit	Required for altering water distribution lines and connecting a new water-heating system.

Possible add-ons

These items are not included in the estimate range above. They may change after an on-site review.

Item	Trade	Possible range	What would confirm it
Upsize the existing gas line to 3/4" black iron pipe if pressure-drop calculations show the current 1/2" line can't support the 199,000 BTU/hr load.	Gas Fitter	$350 - $550	Gas pressure test or sizing calc shows the existing 1/2" line can't carry the 199,000 BTU/hr load.
Supply and install a condensate pump if gravity routing to the basement floor drain is blocked or impossible by elevation.	Plumber	$275 - $450	On-site assessment finds gravity condensate drainage to the floor drain is obstructed or impossible.
Supply and install a new GFCI-protected outlet if the existing 120V outlet is ungrounded or non-compliant with current electrical code.	Electrician	$125 - $200	Existing 120V outlet lacks grounding, isn't GFCI, or is otherwise non-functional on inspection.

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You can keep chatting to ask questions or tweak the project — and when you're ready, a real professional will confirm the details and discuss final pricing, usually after seeing the space in person.

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