Quick Answer
What Toronto homeowners need to know about knob-and-tube and insurance:
- Many insurers flag active knob-and-tube as elevated fire risk — some ask for an inspection, some set a removal deadline, some apply a surcharge.
- Requirements differ by insurer. Confirm your own policy's stance in writing before assuming the worst.
- Documented removal under an ESA permit — ending in an ESA Certificate of Acceptance — is the paperwork insurers and buyers want to see.
If you own an older home in Toronto — the Beaches, Riverdale, Leslieville, the Annex, Parkdale, Cabbagetown — there's a good chance knob-and-tube wiring has come up at some point. Usually it surfaces during a home purchase, a renovation, or an insurance renewal. And when it comes up with an insurer, it tends to get people's attention fast. Here's a straight explanation of why insurers care, what they typically ask for, and how to get to the other side of it.
What Knob-and-Tube Actually Is
Knob-and-tube was the standard wiring method in Toronto homes built before roughly the 1950s. It uses individual insulated conductors run through ceramic knobs (to hold the wire away from framing) and ceramic tubes (to pass safely through joists). It was a reasonable system for its era. The problem is that "its era" was 70 to 100 years ago, and the electrical demands of a modern household — plus decades of well-meaning modifications — have left most of it far from ideal. If you want the deeper safety picture, we cover it in is knob-and-tube wiring dangerous.
Why Insurers Care About Knob-and-Tube
Insurers are in the business of pricing risk, and knob-and-tube touches several risk factors at once. Understanding what specifically worries them helps you have a productive conversation with your broker.
- Age. The wiring is typically 60 to 100 years old. Insulation degrades, becomes brittle, and can crack or flake off over decades.
- No ground conductor. Knob-and-tube has no equipment grounding conductor. That limits your ability to safely run modern grounded appliances and electronics, and it's a fundamental difference from today's wiring.
- Insulation contact. The system was designed with air around the conductors to dissipate heat. When later owners add blown-in or batt insulation in walls and attics, the wiring gets buried, traps heat, and the fire risk climbs. This is one insurers ask about specifically.
- Amateur modifications. Over a century, most knob-and-tube has been spliced, extended, or tied into modern wiring — often by non-professionals, sometimes in junction points buried inside walls. Improvised connections are a common failure point.
Typical Insurer Responses
There's no single, industry-wide rule here, and that's important to understand. Different insurers handle knob-and-tube very differently. That said, the responses we see fall into a few recognizable patterns:
- A request for inspection. Many insurers will ask for a written assessment from a Licensed Electrical Contractor confirming the condition of the wiring and whether active knob-and-tube is present.
- A remediation timeline. Some insurers renew the policy on the condition that active knob-and-tube be removed within a set period — sometimes months, sometimes a year or more.
- A surcharge or condition. Some may apply an additional premium or attach conditions while the wiring remains.
- Declining a new policy. A smaller number of insurers won't write a new policy on a home with active knob-and-tube at all.
Because responses vary this much, the single most useful thing you can do is ask your insurer, in writing, exactly what they require. Don't assume a friend's experience with a different company applies to yours.
The Inspection and Documentation Path
When an insurer asks for an inspection, they want a clear, written picture of what's actually in the walls. A Portman electrical safety inspection is a contractor assessment: we examine the visible and accessible components of your system — the panel, accessible junction boxes, attic and basement runs, device connections — and provide a written report on condition and any active knob-and-tube we can identify.
It's important to be honest about the limits here. Our assessment is not an ESA inspection, and because it's non-destructive, we can't see wiring concealed behind finished walls and ceilings. We report on what's accessible, and we'll tell you plainly where we can and can't see. Many insurers accept this kind of contractor report; some may have their own specific format or requirements, so it's worth confirming what yours will accept before booking.
When actual rewiring happens, that's a separate and more formal process. We file an ESA Notification of Work (the electrical permit) before starting and coordinate the ESA inspection. Once ESA reviews and accepts the work, ESA — not Portman — issues the Certificate of Acceptance. That certificate is the gold-standard documentation for both your insurer and any future buyer. If you're new to how ESA inspections work, our guide on the ESA inspection process in Ontario walks through it.
Partial vs Full Replacement
Homeowners often hope they can remove "just the bad parts." Sometimes that's realistic, sometimes it isn't — it depends on how much active knob-and-tube remains and what your insurer will accept.
- Partial replacement can make sense when most of the home has already been rewired and only a few original circuits remain. The catch: any knob-and-tube being "abandoned in place" must be genuinely disconnected and dead, not simply left capped and live. An inspector will look for this.
- Full replacement is what many insurers ultimately want, and it's the cleanest outcome — every original conductor removed and replaced with modern grounded wiring. It's more disruptive and more expensive, but it ends the conversation permanently.
Full rewiring is frequently paired with a service upgrade, because older homes with knob-and-tube often also have undersized service. If your panel is part of the picture, our panel and service upgrade work often happens in the same project. You can see how the full removal process works on our knob-and-tube rewiring in Toronto page.
What About the Cost?
The honest answer is that it varies widely, and anyone quoting a flat number sight-unseen is guessing. The real cost drivers are the size of the home, how much active knob-and-tube actually remains, how accessible the wall and ceiling cavities are, and whether a panel upgrade is needed at the same time. A semi where most circuits were replaced decades ago is a very different job from a fully original Victorian. We assess the specific home before giving numbers.
Can You Do It Yourself?
In Ontario, a homeowner doing electrical work in a home they own and occupy is generally permitted to do so — but a permit (an ESA Notification of Work) and an inspection are still required. That said, knob-and-tube removal is one of the jobs we most strongly advise against tackling yourself. It runs through old, sometimes brittle framing, mixes with modern circuits in ways that are easy to misread, and often hides live splices in unexpected places. If you're hiring anyone, that work must be done by a Licensed Electrical Contractor — and for insurance and resale, professionally documented removal is what carries weight.
Portman Electric
Insurer asking about knob-and-tube? We can help you document it.
As an ECRA/ESA Licensed Electrical Contractor, we assess your wiring, provide a written report, and — when rewiring is needed — file the ESA permit and coordinate the inspection so you get the documentation your insurer wants.
Common Questions About Knob-and-Tube and Insurance
Does knob-and-tube wiring affect home insurance in Toronto?
It often does. Many insurers treat active knob-and-tube wiring as an elevated risk and may ask for an inspection, require remediation within a set timeframe, apply a surcharge, or in some cases decline to write a new policy. Requirements vary by insurer, so the only way to know is to ask yours directly.
Why do insurers care about knob-and-tube wiring?
Knob-and-tube is typically 60 to 100 years old, has no ground conductor, was never designed for today's electrical loads, and is frequently found buried in blown-in or batt insulation — which the system was never meant to contact. Decades of amateur modifications and splices add further risk. Insurers weigh all of this when assessing fire risk.
Will my insurance company cancel my policy if I have knob-and-tube?
Not automatically. Some insurers renew existing policies with conditions, some ask for an electrician's inspection, and some set a deadline to remove active knob-and-tube. A smaller number won't write new policies on homes with it. Because policies differ, confirm your specific insurer's stance in writing.
Can I get an inspection to satisfy my insurer?
Often yes. Many insurers will accept a written assessment from a Licensed Electrical Contractor documenting the condition and extent of any knob-and-tube. A Portman electrical safety assessment inspects visible and accessible components and provides a written report — but keep in mind it can't see wiring concealed behind finished walls, and it is not an ESA inspection.
Do I have to replace all the knob-and-tube at once?
Not always. Some insurers accept a phased plan; others want all active knob-and-tube removed. Partial replacement can make sense when only certain circuits remain, but abandoned-in-place wiring must be truly disconnected, not just capped. Your insurer's requirements drive whether partial work is acceptable.
Does a permit and ESA inspection matter for insurance?
Yes. When rewiring is done under an ESA Notification of Work with an ESA inspection, ESA issues a Certificate of Acceptance once the work is reviewed and accepted. That documentation is exactly what insurers and future buyers want to see as proof the work was done to the Ontario Electrical Safety Code.
Is it safe to just add insulation over knob-and-tube?
No. Knob-and-tube relies on air around the conductors to shed heat, so burying it in insulation traps heat and increases fire risk. This is one of the specific conditions insurers ask about, and it's a common reason a home's wiring gets flagged.
How much does knob-and-tube removal cost in Toronto?
It depends heavily on the size of the home, how much active knob-and-tube remains, wall and ceiling access, and whether a panel upgrade is needed at the same time. Rather than quoting a flat figure, we assess the specific home. The cost drivers matter more than any single number.
Can I remove knob-and-tube myself to save money?
As a homeowner in a home you own and occupy, DIY electrical work is generally permitted in Ontario, but a permit and inspection are still required — and we strongly advise against it here. Knob-and-tube runs through old, sometimes brittle framing and mixes with modern wiring in ways that are easy to get wrong. Hired work must be done by a Licensed Electrical Contractor.
Will replacing knob-and-tube lower my insurance premium?
It may. Once active knob-and-tube is removed and documented, many insurers will remove a surcharge or condition — but this varies. Provide your insurer with the ESA Certificate of Acceptance and any contractor documentation, and ask how it affects your policy.