What Is Knob and Tube Wiring?
An outdated electrical system with no grounding, common in houses built before 1950. Insurers see it as a fire risk.
Free to compare
Insurers drop houses with knob and tube wiring because the insulation wears out over decades and there's no ground wire, so it can't handle what a modern house puts on it, like window units and space heaters on one circuit. Most insurers want it replaced, either throughout the house or in the rooms still using it, before they'll write a new policy. Some will accept a licensed electrician's inspection showing the active wiring is safe. Your electrical panel or an inspection will tell you what your declarations page won't.
A wiring problem doesn't rule out coverage
One insurer's rejection isn't every insurer's answer. Some weigh the rewiring, the inspection, or the age of the system differently. Comparing quotes shows whether another company will cover the house as it stands.
Can knob and tube wiring be fixed instead of replaced?
Rewiring a whole house is expensive, so it's worth knowing what counts as fixing the problem instead of replacing everything. Some insurers will accept partial rewiring, where the rooms or circuits still on knob and tube get updated to modern wiring and the rest of the house, if any part was already rewired by a previous owner, stays as is. Whether that's enough depends on how much of the house is still on the old system and what each insurer's underwriting guidelines say.
An inspection by a licensed electrician is the other path. The electrician checks the condition of the insulation, the connections, and whether the circuits are overloaded for what the house actually runs now. A report showing the wiring is in good condition and not a fire hazard can be enough for some insurers, even without replacing anything. Not every insurer accepts this option, and the ones that do may still want the work scheduled within a certain time after the policy starts.
If a lender is involved, ask what they require separately from what the insurer requires. Lenders sometimes want proof of safe wiring before closing or before renewing a mortgage, and that requirement doesn't disappear just because an insurer accepted the house as is. Keep any inspection report or electrician's invoice. It documents the condition of the wiring at a point in time, which matters if a future insurer asks the same question again at the next renewal.
Cost is the real tradeoff here. A full rewire removes the issue permanently and tends to open up more insurers willing to write the policy, but it costs far more than an inspection. Partial rewiring sits in between, fixing the highest-risk circuits without touching the whole house. None of these choices change the fact that the wiring itself is the reason the house is harder to insure, so whichever path gets chosen, it helps to ask the insurer in advance what documentation they'll want to see.
Does knob and tube wiring affect more than insurance?
Insurance is usually what brings knob and tube wiring to someone's attention, but the wiring itself has effects beyond the policy. It was designed for a world without microwaves, air conditioners, or phone chargers in every room. A circuit built for a few lamps and a radio wasn't meant to run what a modern kitchen or home office draws today. That mismatch is why insurers worry about it, and it's also why some homeowners notice tripped breakers, warm outlets, or flickering lights in rooms still on the old system.
The wiring's condition matters as much as its age. Knob and tube that has sat undisturbed for decades, with its rubber or cloth insulation intact and no signs of prior tampering, can still be functioning as designed. The problems tend to show up where someone added insulation around the wires, which knob and tube was never meant to have touching it, or where a previous repair spliced in modern wire without the right connectors. An electrician's inspection looks at exactly these things, not just whether the system is old.
Selling the house later is worth thinking about now. A buyer's lender will likely ask the same questions an insurer does, and a buyer's own insurance search will run into the same obstacle. Some sellers rewire before listing to avoid the issue coming up during a sale, since a house that's hard to insure is also a house that's harder to finance. Others disclose the wiring and let the price reflect it. Either way, documentation from an inspection or rewiring job becomes part of the house's history, something a future buyer's insurer or lender will likely want to see.
None of this changes what's needed right now, which is coverage before the current policy ends. But knowing that the wiring is a long-term fact about the house, not just a line item on one insurer's checklist, helps in deciding whether to rewire fully, rewire partially, or document the system's condition and move forward with what the house has.
Before the deadline, check your panel
Find out how much of the house still runs on knob and tube and whether a prior owner already rewired part of it. That answer, plus any electrician's report, shapes which insurers will write the policy.
