How much does it cost to install a tankless water heater during a basement renovation in the GTA?

Tankless water heater installation in the GTA typically runs $3,000–$6,000 for a natural gas unit, or $4,000–$8,000 for an electric unit, including equipment and labour. During a basement renovation, it's one of the smarter upgrades to tackle — the space is already disrupted, trades are on-site, and you can plan the mechanical room layout properly from the start.

What Drives the Cost

The equipment itself is the largest variable. A mid-range natural gas tankless unit (Navien, Rinnai, or Noritz are common in the GTA) runs $1,200–$2,500 for the unit alone, depending on flow rate capacity. A whole-home unit sized for a typical GTA house (2–3 bathrooms) needs to deliver at least 8–10 gallons per minute. Electric tankless units are less common in Canadian homes because they require enormous electrical capacity — often 150–200 amps just for the water heater — which makes them impractical for most GTA homes on 100-amp or 200-amp service.

Labour costs in the GTA are significant. A licensed plumber will charge $800–$1,800 for the installation itself, but the full scope often includes gas line work (requiring a licensed gas fitter), new venting through the rim joist or exterior wall (tankless units require Category III stainless steel venting, not the old flue from a tank), and potentially a dedicated gas line upgrade if your existing line can't supply the required BTU load. Some older GTA homes — particularly post-war bungalows in Scarborough, North York, and Etobicoke — have undersized 3/4-inch gas lines that need upgrading to 1-inch to support a high-demand tankless unit, adding $500–$1,500 to the project.

Permit and Inspection Requirements

This work requires permits in Ontario — specifically a plumbing permit and a gas permit, both pulled by the licensed trades doing the work. The gas work must be inspected by the Technical Standards and Safety Authority (TSSA). If you're also adding a basement bathroom as part of the renovation, coordinate the plumber's visits so rough-in, water heater installation, and final inspections happen in logical sequence — it saves mobilization costs.

Basement Renovation Timing Advantage

Installing during a basement renovation is genuinely the right time to do this. The mechanical room walls aren't drywalled yet, so running new gas lines, water lines, and venting is straightforward. If you're adding a basement bathroom or wet bar, the plumber is already on-site for rough-in work — combining the water heater installation in the same visit reduces labour costs compared to a standalone job. Plan the mechanical room to give the unit at least 12 inches of clearance on the service side, and make sure the condensate drain line (all modern condensing tankless units produce acidic condensate) is routed to a floor drain.

One Thing to Watch

If your home still has a conventional tank water heater sitting in the basement, confirm whether it's owned or rented. A large percentage of GTA homes have rented water heaters through Enercare or other providers — breaking a rental contract can cost $300–$1,500 in buyout fees depending on the unit's age. Factor that into your budget before committing to the upgrade.

For the plumbing and gas work specifically, you'll want a licensed plumber and gas fitter — this isn't a DIY scope under any circumstances. You can find licensed plumbing and mechanical contractors through the Toronto Construction Network at torontoconstructionnetwork.com. If you're planning a full basement renovation alongside this upgrade, Toronto Basement Remodeling can match you with a local contractor who can coordinate all the trades for free.