How much does knob and tube rewiring cost in Ontario?

Knob and tube wiring replacement in Ontario typically costs $8,000-$25,000 CAD depending on home size. Small homes (800-1,200 sq ft) cost $8,000-$12,000, medium homes (1,200-2,000 sq ft) cost $12,000-$18,000, and large homes (2,000-3,000 sq ft) cost $18,000-$25,000.

Why is knob and tube wiring dangerous?

Knob and tube wiring is dangerous because it has no ground wire (shock and fire risk), the rubber insulation deteriorates and becomes brittle over time, circuits are often overloaded beyond their 1920s-era capacity, and contact with modern insulation creates fire hazards. Many DIY modifications over the decades also compromise safety.

Will insurance cover a home with knob and tube wiring?

Many major insurers (TD, Aviva, Intact) refuse to insure homes with knob and tube wiring or charge significantly higher premiums ($500-$1,500+ extra annually). You may need specialty high-risk insurers. After K&T replacement, you receive an ESA certificate that allows you to obtain standard insurance rates.

Can I do a partial knob and tube replacement?

Yes, partial replacement is possible if only some circuits have K&T. However, most insurers require complete removal for standard rates. Partial replacement may cost $3,000-$8,000 but may not satisfy insurance requirements. Full replacement is usually recommended.

How long does knob and tube rewiring take?

Knob and tube rewiring typically takes 3-7 days depending on home size and complexity. Small bungalows may be completed in 3-4 days, while larger Victorian homes may take 5-7 days. Work done during renovations when walls are open is faster and less expensive.

How do I know if my home has knob and tube wiring?

Signs of knob and tube wiring include: home built before 1950, ceramic knobs visible in basement or attic, two separate wires (not bundled in cable), fabric or rubber-covered wires, fuse box instead of breakers, and no three-prong grounded outlets. A licensed electrician can perform a K&T assessment.

Knob and Tube Wiring Replacement Cost in Ontario

Own an older Ontario home with knob and tube wiring? Learn about the costs, risks, and process of replacing this outdated electrical system. All prices in Canadian dollars.

Get Free Quote: +1 866 565 5427

Knob and tube wiring was the standard electrical wiring method in Ontario homes built between the 1880s and 1950s. While it was considered safe when installed, this century-old technology simply wasn't designed for today's electrical demands and poses significant fire and safety risks.

If your home has knob and tube wiring, replacing it is one of the best investments you can make for your family's safety and your home's value.

What is Knob and Tube Wiring?

Knob and tube (K&T) wiring gets its name from the ceramic knobs that hold wires in place and ceramic tubes that protect wires passing through wooden joists and studs.

Key characteristics of knob and tube wiring:

Two separate wires (hot and neutral) run through the home
No ground wire — a major safety concern
Ceramic insulators instead of modern plastic sheathing
Wires run openly through wall cavities
Typically found in homes built before 1950

Common in older Toronto neighbourhoods like The Annex, Cabbagetown, Leslieville, Roncesvalles, High Park, and throughout Hamilton, Burlington, and other historic Ontario communities.

Why Knob and Tube Wiring is Dangerous

⚠️ Fire Hazard Warning

The Electrical Safety Authority (ESA) and most insurance companies consider knob and tube wiring a significant fire risk. Many insurers refuse to cover homes with active K&T wiring or charge substantially higher premiums.

Major Risks Include:

No ground wire: Increased shock and fire risk with modern appliances
Deteriorated insulation: Rubber insulation becomes brittle and cracks over decades
Overloaded circuits: Designed for 1920s loads (lights and radio), not modern appliances
Insulation contact: Dangerous when blown-in insulation touches K&T wires
DIY modifications: Often improperly modified over the years
Hidden damage: Problems may be concealed inside walls

Knob and Tube Replacement Costs

The cost to replace knob and tube wiring varies significantly based on your home's size, accessibility, and the extent of the existing K&T system. Most homes require a full rewire plus a panel upgrade.

Average Ontario Costs (CAD)

Small Home (800-1,200 sq ft) $8,000 - $12,000

Medium Home (1,200-2,000 sq ft) $12,000 - $18,000

Large Home (2,000-3,000 sq ft) $18,000 - $25,000

Per Square Foot $8 - $15

Panel Upgrade (100A to 200A) $1,400 - $1,800

ESA Inspection & Permits $200 - $500

Factors That Affect Your Cost

Home Size & Layout

$8 - $15 /sq ft

Larger homes and multi-storey layouts require more wire, outlets, and labour. Complex layouts with finished basements add to the cost.

Wall Access

Varies

Open walls (during renovation) are cheaper to rewire. Finished walls may require cutting access holes that need patching afterward.

Number of Circuits

$150 - $300 /circuit

Modern homes need 15-30+ circuits. Older homes often had only 4-6 circuits, so you're adding significant capacity.

Panel Upgrade

$1,400 - $1,800 additional

Almost always required with K&T replacement. Old 60A fuse boxes must be upgraded to 200A breaker panels.

Partial vs. Full Replacement

Can I Replace Just Part of the K&T?

While partial replacement is technically possible, we generally recommend full replacement for several reasons:

Insurance requirements: Many insurers require ALL K&T to be removed
Code compliance: Mixing old and new wiring can create issues
Hidden problems: Partial removal may miss damaged sections
Cost efficiency: It's more economical to do it all at once
Home sale: Buyers and inspectors want K&T fully removed

Partial replacement may be acceptable when: You're renovating one area and plan to complete the rest later, or your insurance accepts a phased approach.

Insurance & Knob and Tube Wiring

One of the biggest drivers for K&T replacement is insurance. Here's what Ontario homeowners typically face:

⚠️ Insurance Reality

Many major insurers (TD, Aviva, Intact, etc.) will not insure homes with active knob and tube wiring, or charge premiums 2-3x higher than normal.

Denial of coverage: Some insurers flat-out refuse K&T homes
Higher premiums: Those that do insure may charge $500-$1,500+ extra annually
Specialty insurers: You may be forced to use high-risk insurers
Claim issues: Electrical fires with K&T may face claim disputes

After K&T replacement, you'll receive an ESA certificate of inspection that allows you to get standard home insurance rates — often saving hundreds per year.

Quick Reference: K&T Replacement Pricing

Bungalow / Small Home

$8,000 - $12,000 CAD

800-1,200 sq ft. Single storey, accessible attic. Includes panel upgrade and ESA inspection.

2-Storey Semi / Townhouse

$12,000 - $18,000 CAD

1,200-2,000 sq ft. More circuits, multiple floors. Full rewire with 200A panel.

Large Victorian / Detached

$18,000 - $25,000 CAD

2,000-3,000 sq ft. Complex layout, multiple floors, many circuits. Complete modernization.

During Renovation

Save 20-30%

If walls are already open for renovation, rewiring is significantly cheaper. Plan ahead!

Knob and Tube Removal Service Areas

KoljiBros Electrical specializes in knob and tube removal in older neighbourhoods across the GTA and Southern Ontario.

Toronto Downtown Toronto High Park The Junction Bloor West Hamilton Burlington Oakville Etobicoke Kingsway

Get Your Free K&T Assessment Today

Not sure if your home has knob and tube wiring? KoljiBros Electrical offers free assessments for Ontario homeowners. We'll inspect your electrical system and provide an honest quote for replacement if needed.

Call Now: +1 866 565 5427 Request Free Assessment

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