Does Knob & Tube Wiring Affect Your Home Insurance? (2026 Guide)

If your Kitchener-Waterloo home was built before 1950 and hasn't been fully rewired, there's a good chance some of the original knob & tube wiring is still active behind your walls. On its own, that's a wiring style — but it's also one of the most common reasons homeowners in this region get an unpleasant surprise from their insurance company.

What Knob & Tube Wiring Actually Is

Knob & tube was the standard wiring method in Canada from the early 1900s through the 1940s. It uses ceramic knobs to route wires along framing and ceramic tubes to protect wires passing through joists — with individual wires wrapped in rubber or cloth insulation, no ground wire, and no sheathing around the conductors like modern wire has.

It wasn't a bad system for its time. The problem is what happens to it 70-100 years later.

Why It Becomes a Problem Over Time

Two things change as knob & tube ages, and both matter:

• The insulation degrades. Rubber and cloth insulation gets brittle and cracks with age, which can expose bare wire.

• It wasn't built for modern loads. Knob & tube was designed for lighting and small appliances — not the AC units, kitchen appliances, and electronics a modern household runs simultaneously.

There's one more issue specific to energy retrofits: the Ontario Building Code prohibits insulation from directly contacting energized knob & tube wiring, because trapped heat accelerates the wire's insulation breakdown and can ignite surrounding material. If you're planning to add attic insulation for energy efficiency and you have active knob & tube up there, that's a real conflict — not a technicality.

Why Insurance Companies Care

This is where it gets concrete for a lot of homeowners. Insurers treat active knob & tube as a meaningful risk factor, and the response varies by company:

• Some insurers refuse to write a new policy on a home with active knob & tube at all

• Some will insure it but charge significantly higher premiums

• Some will provide coverage conditional on an electrical inspection, or give you a window of time to replace it

The Electrical Safety Authority allows homeowners to keep knob & tube if it meets specific criteria and passes inspection — but ESA approval doesn't override what your insurer decides. And since mortgage lenders require home insurance, if your insurer won't cover a knob & tube home, replacing the wiring often isn't optional in practice, even if it's technically allowed to stay.

What Replacement Costs in the KW Region

Costs depend heavily on your home's size and how accessible the wiring is (plaster walls cost more in labor than drywall):

• Full home rewire: roughly $8,000 – $20,000+, depending on square footage — a rough rule of thumb is $4,000–$8,000 per 1,000 sq ft

• Targeted circuit removal (replacing specific circuits rather than the whole house): roughly $400 – $800 per circuit

• Panel upgrades are frequently bundled in, since older knob & tube homes often still have undersized fuse panels

Request a free quote and we'll assess your specific home rather than guessing from a range.

The Process

1. Assessment — we identify where knob & tube is still active and where it's already been replaced

2. Quote — a clear plan and price, whether that's a full rewire or targeted circuit work

3. Permit — we pull the ESA permit for the work

4. Rewiring — old wiring is replaced with modern, grounded circuits, done to minimize wall/ceiling disruption where possible

5. ESA inspection — the completed work is inspected and signed off

6. Documentation — you get a Certificate of Inspection to provide your insurer

Why This Is a Job for a Licensed Electrician

Between the insurance stakes and the fire risk, this isn't a corner to cut. Unpermitted or DIY work on knob & tube can void your insurance entirely — the opposite of what you're trying to fix. This is exactly the kind of job where hiring a Master Electrician who documents everything to ESA standards pays for itself the first time your insurer asks for proof.

If you're also dealing with aluminum wiring from a slightly newer era of your home, we've covered what that involves separately — it's a different issue with a different fix.

Get It Checked, for Free

Power KW assesses knob & tube wiring for homeowners across Kitchener, Waterloo, Guelph, and Cambridge — free, no pressure. Call or text 519-573-9889, or request a free quote.

Power KW is a Master Electrician company (ESA Lic# 7015811) serving Kitchener, Waterloo, Guelph, and Cambridge.

FAQ

Will my insurance company refuse to cover a home with knob & tube wiring?

It depends on the insurer. Some refuse new policies outright, some charge higher premiums, and some require an inspection or a timeline for replacement. Since mortgage lenders require insurance, an insurer's refusal can effectively force replacement.

Is knob & tube wiring illegal in Ontario?

No. The ESA allows existing knob & tube to remain if it meets specific criteria and passes inspection. The issue is more often with insurance companies than with legality.

How much does it cost to remove knob & tube wiring in Kitchener-Waterloo?

A full home rewire typically runs $8,000–$20,000+ depending on home size, roughly $4,000–$8,000 per 1,000 sq ft. Targeted circuit-by-circuit removal runs about $400–$800 per circuit. Get a free quote for your specific home.

Can I add attic insulation if I still have knob & tube wiring up there?

Not directly over active, energized knob & tube — the Ontario Building Code prohibits insulation from contacting it, since trapped heat accelerates insulation breakdown and increases fire risk. That wiring needs to be addressed before or during an insulation upgrade.

How do I know if my home still has active knob & tube wiring?

Homes built before 1950 that haven't been fully rewired are the most likely candidates. A licensed electrician can inspect your panel and accessible wiring to confirm what's active versus already replaced.