What is the price to relocate a furnace and reroute all ductwork in a GTA home?

Relocating a furnace and rerouting the entire duct system in a GTA home typically costs $8,000 to $25,000 or more, depending on where the furnace is moving, how far the new duct runs need to travel, the size of the home, and whether the existing ductwork can be partially reused or must be completely replaced. This is one of the most involved HVAC projects a homeowner can undertake, and it requires careful planning with both an HVAC contractor and often a general contractor handling the structural and finishing work.

The furnace relocation itself — disconnecting the existing unit, moving it to the new location, reconnecting gas, electrical, venting, condensate drainage, and combustion air — typically runs $2,000 to $5,000 for the mechanical work alone. Gas line extension or rerouting must be performed by a TSSA-registered contractor, and the new gas connection requires a TSSA inspection. Electrical work for the new furnace location, thermostat wiring, and any associated circuits requires an ESA-Licensed Electrical Contractor. The furnace exhaust flue and fresh air intake must be rerouted to meet Ontario Building Code clearance requirements from windows, doors, and property lines — this alone can add $500 to $2,000 depending on the new venting path.

The ductwork rerouting is where costs escalate. A complete trunk line reroute for a typical 1,500 to 2,500 square foot GTA home runs $5,000 to $15,000, including new supply and return plenums ($200 to $600 each), new trunk lines, branch runs to each room, register boots, and all fittings. If the furnace is moving from one end of the basement to the other, every supply and return run changes direction and length, essentially requiring a brand-new duct system designed with Manual D calculations for the new layout. If you are moving the furnace from the basement to the attic or a mechanical closet on the main floor, costs climb higher because of the additional structural work, attic duct insulation requirements (minimum R-8 duct wrap in unconditioned spaces), and the complexity of routing ducts vertically through walls and chases.

Common reasons GTA homeowners relocate furnaces include basement renovations where the furnace occupies valuable living space, kitchen or bathroom expansions that conflict with the existing mechanical room, converting a basement apartment into rental space (each unit needs its own mechanical system under the OBC), or improving the duct layout in older post-war homes where the original furnace location creates excessively long duct runs to some rooms. In older Scarborough, North York, or Etobicoke homes with the original gravity furnace location in the centre of the basement, moving to a corner mechanical room frees up significant floor space but requires complete duct redesign.

A building permit is required for this scope of work — expect $400 to $800 in permit fees from the City of Toronto or your local municipality. The permit covers mechanical, and you will likely need separate electrical and gas permits as well. Budget a minimum of $10,000 to $15,000 for a straightforward basement-to-basement relocation in a mid-size GTA home, and $15,000 to $25,000 or more for complex relocations involving floor changes or major rerouting. Get at least three detailed quotes that break out furnace relocation, ductwork, gas, electrical, and permit costs separately so you can compare accurately.