Knob and Tube Wiring Replacement Cost in Ontario

Knob and Tube Wiring Replacement Cost in Ontario

Knob and tube wiring was the standard in Canadian homes built before the 1950s. If your home still has it, you may be facing pressure from insurance companies, home inspectors, or site renovation contractors to have it replaced. Here is what knob and tube wiring replacement actually costs in Ontario and why the project almost always includes a panel upgrade.

How Much Does Knob and Tube Wiring Replacement Cost in Ontario?

Knob and tube rewiring in Ontario starts at $10 per square foot, based on the finished area of the home. This covers the labour and materials to remove the old knob and tube wiring and replace it with modern copper wiring that meets the Ontario Electrical Safety Code (OESC).

In addition to the per-square-foot rewiring cost, most knob and tube replacement projects also require a panel upgrade. Homes with original knob and tube wiring typically have outdated 60-amp or 100-amp panels that cannot safely support modern electrical loads. Panel upgrade pricing is quoted separately based on your existing service type.

The total cost of your project depends on the size of the home, the extent of the original knob and tube system, and whether the wiring has been partially replaced or modified over the years. A site assessment by a licensed electrical contractor is required to provide an accurate quote.

What Is Knob and Tube Wiring?

Knob and tube wiring uses ceramic knobs to hold wire runs along structural members and ceramic tubes to pass wires through joists and studs. The wiring has two conductors — a live and a neutral — with no ground wire. This is one of the primary reasons it is considered a safety hazard by today’s standards.

Key issues with knob and tube wiring include:

• No ground wire — Modern appliances and electronics require a grounded circuit for safe operation and surge protection. Knob and tube provides no ground.
• Deteriorated insulation — The cloth and rubber insulation used on knob and tube wiring degrades over time. It becomes brittle, cracks, and can expose live conductors.
• Incompatibility with insulation — Knob and tube wiring is designed to dissipate heat through air. When covered by attic insulation — a common renovation practice — it cannot cool properly, creating a fire hazard.
• Insurance and resale issues — Many insurance companies in Ontario refuse to insure homes with active knob and tube wiring, or charge significantly higher premiums. It can also be a deal-breaker during a home sale.

Does Knob and Tube Replacement Require an ESA Permit?

Yes. Rewiring a home is one of the most significant electrical projects a licensed electrical contractor undertakes, and it requires an ESA permit. The Electrical Safety Authority will inspect the work after completion to confirm the new wiring meets Ontario Electrical Safety Code standards.

Only a licensed electrical contractor can legally pull this permit and perform the rewiring. In Ontario, only licensed electrical contractors and master electricans are permitted to perform electrical work on residential, commercial, or industrial properties.

What Does the Rewiring Process Involve?

A full knob and tube replacement involves removing the original wiring throughout the home and running new copper wiring to all outlets, switches, and fixtures. This work typically requires opening walls and ceilings to access wire runs. In a finished home, some drywall patching may be needed after the wiring is complete.

The project scope also includes:

• Assessment of any aluminium wiring that may have been added during partial rewires between the 1960s and 1980s
• Replacement of all outlets and switches that are connected to the old wiring
• Installation of proper grounded receptacles throughout the home
• Panel upgrade if the existing panel is insufficient for the rewired home’s load
• ESA permit and final inspection

What About Aluminium to Copper Rewiring?

Some Ontario homes built between roughly 1965 and 1980 have aluminium branch circuit wiring instead of copper. Aluminium wiring expands and contracts at a different rate than copper, which can loosen connections over time and create fire hazards. Replacing aluminium branch wiring with copper also starts at $10 per square foot, with a panel upgrade quoted separately where required.

If your home has a combination of knob and tube and aluminium wiring from partial rewires over the decades, a licensed electrical contractor will assess the full scope at the initial site visit and provide a complete quote.

Get a Quote for Knob and Tube Wiring Replacement

EZSMART provides full home rewiring services for residential properties across Ontario. We assess your existing wiring system, explain the full scope of work, and provide a clear quote before any work begins. All permits and ESA inspections are included.

Contact us today to schedule a site assessment for your knob and tube or aluminium wiring replacement project.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp