What is the average cost of sheet metal ductwork fabrication for a custom Toronto home?

Custom sheet metal ductwork fabrication and installation for a custom Toronto home typically costs $8,000 to $25,000 or more, depending on the home's size, the number of zones, ceiling and wall configurations, and the complexity of the duct layout. Custom homes generally cost 30 to 50 percent more for ductwork than production-built homes because the duct system must be designed and fabricated specifically for the unique floor plan, architectural features, and mechanical layout — there are no cookie-cutter solutions.

The cost breaks down into three major components. Design and engineering runs $1,000 to $3,000 and includes Manual J heating and cooling load calculations for each room, Manual D duct sizing and layout design, and coordination with the architect and mechanical engineer. This step is non-negotiable for a custom home — guessing at duct sizes in a custom build leads to comfort problems that are extremely expensive to fix after the walls are closed. Fabrication of the sheet metal ductwork itself costs $12 to $30 per linear foot for rectangular trunk ducts and $8 to $20 per linear foot for round branch runs, with custom fittings (offsets, transitions, reducers, and register boots) adding $40 to $150 each. A typical 3,000 to 4,000 square foot custom home might have 150 to 300 linear feet of ductwork and 30 to 60 fittings. Installation labour in the GTA runs $50 to $90 per hour for experienced sheet metal workers, and a custom home duct installation typically requires 40 to 80 labour hours depending on complexity.

Custom homes often have architectural features that significantly increase ductwork costs. Cathedral ceilings eliminate attic space for duct runs, requiring ducts to be routed through soffits, bulkheads, or between floor joists — adding design complexity and fabrication cost. Open-concept layouts with large great rooms need careful supply register placement and oversized return air to handle the volume. Multi-storey homes require vertical chases for duct risers, which must be coordinated with the structural design. Radiant floor heating in some zones combined with forced air in others requires a hybrid mechanical design. High ceilings (10 to 12 feet) need higher supply air velocities to push conditioned air down to the occupied zone.

For exposed ductwork in modern or industrial-style custom homes — increasingly popular in GTA new builds — spiral round duct is the preferred choice at $10 to $25 per linear foot installed. Spiral duct has a clean, architectural appearance and can be powder-coated in custom colours ($5 to $10 per linear foot additional). Exposed ductwork installations require cleaner fabrication, polished welds, and visible hangers, which adds 15 to 25 percent to the cost compared to concealed installations.

Ontario Building Code compliance adds specific requirements. Fire dampers are required at all duct penetrations through fire-rated assemblies. Make-up air is required if any exhaust hood exceeds 75 litres per second. All ductwork must be sealed with mastic and UL 181 tape. A mechanical permit from the City of Toronto or your municipality is required, typically $400 to $800 for a custom home.

Start the ductwork design process early — ideally during the architectural design phase, not after framing. Get matched with experienced sheet metal contractors through Toronto Ductwork and the Toronto Construction Network for detailed quotes on your custom home project.