How do I choose between a centralized and decentralized duct layout for my Toronto home?

For most GTA homes, a centralized duct layout with a single furnace and air handler is the most practical and cost-effective choice — but larger homes, multi-storey additions, and homes with persistent comfort problems may benefit from a decentralized approach using two or more smaller systems. The right answer depends on your home's size, layout, number of storeys, and your comfort priorities.

A centralized layout uses one furnace or air handler located in the basement (the standard setup across the GTA), with a trunk duct system branching to every room in the house. This is simpler to install, costs less upfront ($3,000 to $15,000 for the duct system), and requires maintaining only one piece of equipment. For single-storey homes, bungalows, and compact two-storey homes under 2,500 square feet, a well-designed centralized system handles heating and cooling effectively. The key is proper duct sizing — Manual D calculations ensure each branch delivers the right airflow to each room based on its heating and cooling load.

The limitation of centralized systems shows up in larger and taller homes. A single furnace in the basement pushing air up to a second or third floor through long duct runs loses efficiency with every foot of distance and every turn. The further a room is from the furnace, the less airflow it receives. This is why second-floor bedrooms in many Toronto two-storey homes are uncomfortably hot in summer and sometimes too cool in winter — the ductwork simply cannot deliver enough conditioned air that far from the source. Closing registers on the main floor to force more air upstairs is a common homeowner reaction, but it actually damages the system by increasing static pressure and causing air leaks at duct joints.

A decentralized layout solves this by using two or more smaller systems, each serving a portion of the home. The most common configuration in the GTA is one system for the main floor and basement, and a second system for the upper floors — often with the upper system's air handler installed in the attic or a second-floor mechanical closet. Each system has shorter duct runs, delivers more consistent airflow, and can be controlled independently with separate thermostats. This effectively creates two zones without the complexity of motorized zone dampers.

The cost difference is significant. A decentralized two-system setup costs roughly $20,000 to $40,000 for equipment and ductwork combined, compared to $8,000 to $20,000 for a single centralized system. You also have two filters to change, two sets of maintenance, and eventually two units to replace. However, the comfort improvement in a large or multi-storey home is substantial, and the energy savings from not over-conditioning the entire house to satisfy one uncomfortable zone can partially offset the higher upfront cost.

A practical middle ground that many GTA homeowners choose is a centralized system with zoning dampers. Motorized dampers installed in the trunk ducts divide the home into 2 to 4 zones, each with its own thermostat. A zone control panel coordinates the dampers and the furnace to direct airflow where it is needed. This costs $2,000 to $5,000 on top of the base duct system and provides much of the comfort benefit of a decentralized layout at a fraction of the cost. Consult with a ductwork professional through the Toronto Construction Network to assess which approach suits your home best.