What does knob-and-tube replacement cost?

Replacing knob-and-tube in a typical home is a whole-house rewire, so the $8,000 to $15,000 range here sits inside published rewire guides: Fixr’s national guide lists whole-home rewiring at $7,191 to $13,384, and Bob Vila lists $9,000 to $15,000 for 3,000 square feet and $12,000 to $20,000 in its panel guide. This is the typical SoCal range as of October 2026 for a standard home. It is not a government figure, and it does not include patching.

How to spot the wiring and what the insulation rule says is on the knob-and-tube replacement page.

What you are replacing

Knob-and-tube is the wiring system in many pre-1940s homes. It has no grounding wire, and it is common in homes built before the 1940s. Your city page shows the local housing age, for example Pasadena or Long Beach.

This is a rewire, so price it like one

The cost logic is the same as a whole-house rewire. Size, wall access and finish repair decide it. What is different here is the age. Houses old enough for knob-and-tube may also have plaster walls or a small panel. Each of those can add work.

Source	Full-rewire range
Bob Vila, 1,250 sq ft home	$7,500 to $15,000
Bob Vila, 3,000 sq ft home	$9,000 to $15,000
Fixr, whole home	$7,191 to $13,384

The knob-and-tube figure of $8,000 to $15,000 sits inside all three rows, which makes it a reasonable planning number for a typical older home.

A staged plan can work

Some homeowners replace the highest-risk circuits first. These are usually the ones with attic insulation over them, heavy appliance circuits, and bedrooms. The partial rewire page shows how that works, and the desk estimate for a partial job is $3,000 to $8,000. A staged plan leaves some old wire in the walls, so ask for a written map of what stays.

Panel and insurance

A house with knob-and-tube often has an old panel, too. If both change at once, the price rises by the panel cost. Read the panel upgrade cost page. If you are selling, a buyer’s inspector may flag the wiring. The home sale inspection guide explains the process.

Questions that separate a real quote from a rough one

Ask the electrician to walk the attic and the panel before pricing. They should be able to say how many circuits are knob-and-tube, where the wire runs, and how it ties into newer wiring. A quote that does not mention the circuit count is a guess. Ask for the cable type, how many new boxes the job needs, and whether the bid assumes open attic access. Those answers explain most of the gap between $8,000 and $15,000.

Permit fees

California requires a permit for rewiring. Permit fees are set by each city; see the permit fees page. For your city, use Los Angeles, Riverside or the county hubs instead of trusting a range. The utility is usually not involved unless the panel or meter changes.

How to compare quotes

1. Does the bid replace all knob-and-tube, or only some circuits?
2. Does it name the cable type and the number of circuits?
3. Who handles access in the attic and crawl space, and any insulation that is in the way?
4. Who patches plaster or drywall, and to what finish?
5. Is the permit in the price, and does the bid mention inspection?

What is not included

Patching, texture and paint, plaster restoration, a new panel unless listed, new fixtures, and any work on the gas, plumbing or structure that the walls reveal. Insurance savings are not counted.