Can I install an ERV without existing ductwork in my older Toronto home?

Yes, you can install an ERV in an older Toronto home without existing ductwork, but the approach is different from a standard ducted installation — and the options range from simple single-point units to fully dedicated duct systems. Many pre-war and post-war Toronto homes in neighbourhoods like the Annex, Riverdale, Leslieville, and Cabbagetown were built with hot water radiator heating or gravity furnace systems that have no ductwork at all, so this is a very common scenario in the GTA.

The most practical option for a ductless older home is a wall-mounted or ceiling-mounted single-room ERV unit. These self-contained units mount on an exterior wall, require only a single penetration through the wall, and provide balanced ventilation for the room they serve. They contain their own heat and moisture recovery core, fans, and filters — no ductwork required. Several manufacturers make units designed specifically for retrofit applications. You would typically install one in the main living area and one in the primary bedroom to cover the spaces where you spend the most time. GTA pricing for a single-room ERV unit runs $800-$2,000 per unit installed, depending on the brand and capacity.

The limitation of single-room units is obvious — they only ventilate the room they are in. Bathrooms, the kitchen, and other bedrooms still lack mechanical ventilation. For whole-house ventilation, you will need to run dedicated ERV ductwork through the home. In older Toronto homes, this is a more involved project but absolutely doable during a renovation.

Running dedicated ERV ducts through an older GTA home typically involves routing small-diameter ducts (3-4 inch round) through closets, soffits built along ceiling edges, or through the basement ceiling and up interior wall cavities. Some installers use semi-rigid small-diameter duct systems designed specifically for ERV retrofit installations — these flexible tubes are easier to snake through existing walls than traditional rigid ductwork. Fresh air supply ducts run to bedrooms and the living room, while stale air exhaust ducts run to bathrooms and the kitchen. The ERV unit itself is usually mounted in the basement or a utility closet. Budget $3,500-$6,500 for a fully ducted ERV installation in an older Toronto home, depending on the number of rooms served and the difficulty of routing ducts through finished spaces.

Why an ERV rather than an HRV for a ductless older home? Toronto summers are humid, with humidex values regularly exceeding 40 degrees. An ERV transfers moisture as well as heat between the air streams. In summer, this means the ERV removes some humidity from the incoming outdoor air before it enters your home, reducing your cooling load. In winter, it retains some indoor humidity in the outgoing air stream, preventing the bone-dry conditions that plague tightly renovated older Toronto homes. If your older home has been updated with new windows, insulation, and air sealing, an ERV is especially important because you have eliminated the natural air leakage that previously provided ventilation.

One important consideration for pre-1945 Toronto homes: if the home has any asbestos-wrapped ductwork, pipe insulation, or vermiculite insulation in the walls, have these materials tested before any ERV installation that involves cutting into walls or ceilings. Professional asbestos abatement adds $2,000-$5,000 to the project but is required by Ontario regulation and essential for your family's safety.