Knob and Tube Wiring Replacement Cost, Room by Room

Knob and tube wiring gets priced two ways: as a terrifying whole-house number that makes homeowners close the tab, or honestly, as a set of circuits that can be replaced in a planned order. The second way is how the work actually happens. San Antonio's oldest neighborhoods, the ones with the porches worth keeping, still hold plenty of it, and the room-by-room frame is what makes the project startable.

Why room by room is the honest unit

Knob and tube runs as individual circuits from the panel through ceramic knobs and tubes, usually one or two circuits per area of the house. Replacement happens at that same granularity: kill the old circuit, run new cable, land it on a modern breaker. Nothing about the method requires doing every circuit the same month. What it does require is a map, so each finished room is genuinely finished, old conductors abandoned dead rather than half-fed.

The per-room numbers

In our book, replacing one accessible circuit, the attic-fed bedroom case, is the Knob and tube circuit replacement task, from $2,189. That is the room-by-room unit: new copper, a modern breaker, the old run disconnected dead, permit included. Starting price. Your tech confirms the final number on site before any work.

Access is the whole spread. A circuit reachable from the attic or crawl space is the good case. A circuit buried in plaster walls that has to be fished without wrecking the finishes takes hours of careful work per drop, and the fished tier of the same task prices that honestly. A room with heavy plaster detail can cost more than the two rooms beside it combined, and knowing that before you start is the point of pricing by circuit.

Where a room needs its device count brought to modern code at the same time, the bigger unit is the Room rewire task, from $3,029, which rewires the room and adds the receptacles the last seventy years of living actually use. Starting price. Your tech confirms the final number on site before any work.

The order that makes engineering sense

• First: kitchens and laundry. The circuits carrying real current are the ones where old insulation and buried splices matter most.
• First, also: anything already showing symptoms. Warm devices, brittle insulation at fixtures, or any circuit that has been spliced into over the decades.
• Second: living areas where insulation has been blown over old conductors in the attic. Knob and tube was designed to shed heat in open air.
• Last: lightly loaded bedroom circuits that test clean. They still go, but they can go in next year's phase without losing sleep.

What replacement looks like from inside the house

The fear underneath the whole-house number is usually drywall, so here is the honest picture. An attic-fed circuit replaces with almost no wall damage: new cable drops from above into the existing device boxes, and the patching is measured in single holes, not walls. A fished circuit needs strategic openings, cut cleanly and sized for repair, and we tell you where before cutting. What a phased rewire feels like from inside is a day or two per phase of a crew in specific rooms, power off in those rooms while the cutover happens, and every evening ending with the circuits either fully on the new copper or fully on the old, never half. The old conductors are disconnected dead at both ends and abandoned in place where code allows, because removing plaster to extract dead wire is expense without safety.

The multipliers that show up mid-project elsewhere

Three conditions turn other companies' knob and tube bids into change orders, so we price them at the walkthrough instead. Insulation blown over old conductors in the attic, common in every energy-retrofit decade since the seventies, slows the tracing work and raises the urgency, since knob and tube was engineered to shed heat into open air. Decades of amateur splices mean the circuit map lies, and the real topology only appears as the work proceeds, which is why our quote follows a real walkthrough with a tester rather than a square-footage formula. And original fuse or early breaker equipment at the panel end often makes the first phase a panel conversation, because landing new copper on failing equipment is half a job. None of this changes the room-by-room math. It changes which rooms go first.

Insurance, and what carriers actually want

For many owners the schedule is set by an insurance renewal, not by the wiring itself. Carriers ask about knob and tube at underwriting, and what satisfies them varies by company. What we can say from the electrical side is that a documented, permitted, staged replacement plan reads very differently to an underwriter than an unknown quantity of original wiring, and each phase we finish is inspected work you can show on paper.

One question always comes up mid-project: what happens to the parts of the old system that still work, the ceramic knobs in the attic, the switch loops, the fixtures. The wiring goes; the fixtures usually stay. A 1920s fixture rewired with new leads at the box keeps every bit of its character, three-way switching gets rebuilt properly with modern cable instead of the borrowed-neutral arrangements the old method used, and the house ends the project with something it has never had: a panel directory that tells the truth, written circuit by circuit as each phase lands. That document alone changes every future electrical decision from archaeology into a lookup.

Room by room is how this project stops being a number that ends conversations and becomes a plan with a first phase. Price the kitchen circuit, schedule it, finish it, and the house is measurably safer that same week, whatever the rest of the calendar says. Every phase after that is a decision you make with real numbers instead of a fear you carry with imaginary ones.

The background on how knob and tube works and how to recognize it is in knob and tube wiring, what to know, and the whole-house framing lives in the cost to rewire a house.

The work is our whole home rewiring service, staged to your house and your renewal date rather than to a contractor's convenience.