Knob-and-Tube Wiring and Insurance: Why You Might Get Denied or Dropped
Many home insurers will not write a new policy — or will non-renew an existing one — on a house with active knob-and-tube (K&T) wiring, and those that do often charge more or require it be replaced within a set period. K&T was standard before the 1950s, but insurers treat it as a fire risk, and it can derail a home purchase at the insurance step. Here’s why it’s flagged, what replacement costs, and how to keep or get coverage.
Why Insurers Flag Knob-and-Tube
K&T wiring isn’t automatically dangerous, but it carries risk factors insurers dislike:
- No ground wire — it’s a two-wire system, so no grounding for modern appliances and electronics.
- Brittle insulation — decades-old rubber/cloth insulation cracks and crumbles, exposing conductors.
- Overheats when buried — K&T was designed to dissipate heat in open air; later insulation packed around it (common in attics) traps heat and is a fire hazard.
- Frequently altered — amateur splices and modifications over a century add risk.
- Undersized for modern loads — not built for today’s electrical demand, leading to overloads.
What This Means for Coverage
| Situation | Typical insurer stance |
|---|---|
| Buying a home with active K&T | May refuse to bind a policy until it’s replaced |
| Existing policyholder | Possible non-renewal or a deadline to replace |
| Partial/inactive K&T | Some insurers accept it if a licensed electrician certifies it’s disconnected/safe |
| High-risk/surplus insurers | May cover at higher premiums |
If you’re buying, get the insurance question answered before closing — a deal can fall apart when coverage can’t be bound. Lenders generally require active insurance.
What It Costs to Replace
Rewiring is the permanent fix and what insurers want to see. Cost depends on home size, access, and finishes:
| Job | Typical cost |
|---|---|
| Partial K&T removal/replacement | $2,000 – $8,000 |
| Whole-house rewire | $8,000 – $30,000+ |
| Electrician inspection/certification | $150 – $500 |
Full ranges and what drives them: cost to rewire a house and when to rewire a house. A rewire is often paired with a panel upgrade and 200-amp service upgrade on older homes.
How to Get or Keep Coverage
- Get an electrician’s inspection documenting the wiring’s condition and how much is active K&T.
- Replace active K&T — the surest path to standard coverage; prioritize buried-in-insulation runs first.
- Get certification that remaining K&T is disconnected or safe, if a rewire isn’t immediate.
- Shop insurers — appetite for K&T varies widely; an independent agent can find carriers that will write it.
- Verify your electrician’s license before this kind of work: how to verify a contractor’s license, and ask the right questions to ask an electrician.
Frequently Asked Questions
Will insurance cover a house with knob-and-tube wiring? Often not on standard terms. Many insurers refuse new policies on homes with active K&T or will non-renew existing ones, citing fire risk. Some will cover it at higher premiums, or if a licensed electrician certifies remaining K&T is disconnected or safe. Replacement is the surest route to standard coverage.
Is knob-and-tube wiring actually dangerous? It isn’t automatically unsafe, but it has no ground wire, uses insulation that becomes brittle with age, and overheats when buried under modern attic insulation. Combined with a century of amateur alterations and undersized capacity, those factors make it a real fire risk — which is why insurers flag it.
Do I have to replace knob-and-tube wiring? Not legally in most cases if it’s existing and functional, but your insurer may require it for coverage, and a lender requires active insurance. Replacing it — at least the active and buried runs — is the reliable way to get and keep standard homeowners insurance and to reduce fire risk.
How much does it cost to replace knob-and-tube wiring? Partial replacement typically runs $2,000–$8,000, and a whole-house rewire $8,000–$30,000 or more depending on size, access, and finishes. An electrician inspection or certification is usually $150–$500. Older homes often pair the rewire with a panel or service upgrade.
Can I buy a house with knob-and-tube wiring? Yes, but resolve insurance before closing. Get an electrician’s inspection, then check whether you can bind a policy — some insurers will require the K&T be replaced or certified safe first. Factor rewiring cost into your offer, since it can be a significant expense.
Last updated: June 15, 2026. Sources: ESFI and CPSC on older wiring fire risk; Insurance Information Institute on older-home underwriting; 2026 rewiring ranges per our electrical cost guides. Coverage rules vary by insurer and state.