How Much Does It Cost to Replace Knob and Tube Wiring? [2026 Data]

In 2026, the national average cost to replace knob and tube wiring is $24,300, typically ranging from $12,000 to $36,600 depending on your home size, number of circuits, and how accessible the wiring is. Because knob and tube wiring poses serious shock and fire risks, this is one replacement you'll want to leave to a licensed electrician.

Knob and Tube Wiring Replacement Cost Breakdown: Key Price Factors

Replacing a knob and tube electrical system involves several cost categories that together determine your total project bill. Key factors include job size, materials, labor, permits, accessibility, and disposal.

Rewiring Cost per Square Foot

Rewiring your home costs an average of $10 to $20 per square foot, with larger homes requiring more wiring, fixtures, switches, and outlets in every additional room. The table below shows how rewiring costs vary by home size.

Removal of Knob and Tube Wiring System

In most cases, electricians working in an older home with outdated wiring cut back the old knob and tube wiring rather than fully removing it, leaving the remainder inside the walls to avoid extensive demolition. If full removal is recommended, expect additional labor and disposal costs on top of the base project price. You should also budget for the cost to repair the drywall or lath, which ranges from $300 for small fixes to $900 for major repairs, plus the cost to repaint the walls, averaging $1,960 for the entire interior.

Materials

The most common materials electricians use for upgrading your knob and tube wiring include:

• Electrical wiring, such as low-voltage, NM (non-metallic), UF (underground feeder), and THHN/THWN wire range in cost from $0.25 to $2.00 per linear foot .

• Old work or retrofit electrical boxes cost between $2 and $6 per box. Retrofit boxes are designed for installation in remodels and renovations, as opposed to new work boxes that are designed to be attached to exposed studs during new construction.

• Wire connectors cost about $0.20 each.

Labor

Professional electricians typically charge $50 to $100 per hour to replace knob and tube wiring, not including materials. Many electricians also price the work per opening, charging a flat rate of $100 to $350 or more per opening for each outlet, fixture, or switch.

Accessibility

Homes with knob and tube wiring were typically built between the 1880s and the 1940s, and their age often makes it harder to access wiring and work spaces. When a home lacks a basement, crawl space, or attic, electricians must open more walls to run new wiring, which increases both labor and repair costs.

Permits

Electrical permit costs range from $10 to $500, with most homeowners paying $100 to $125 per permit depending on the job's size and location. Permits are necessary for this type of electrical work, and skipping them is illegal and can result in fines.

Inspections

Knob and tube wiring replacement requires two inspections: a pre-work site evaluation by a local building inspector and a post-completion inspection to confirm the work meets code. Plan to spend $100 to $150 per inspection.

Upgrade the Electrical Panel

Replacing knob and tube wiring typically requires upgrading your electrical panel, which costs $600 to $4,000 on average. Knob and tube systems run through a 60-amp box that cannot support modern appliances designed for today's 100-amp panels, and the right replacement panel for your home will range from 100 to 400 amps, depending on your household's power needs. Consult your electrician to determine the best panel size for your home.

Additional Knob and Tube Wiring Replacement Costs: What to Budget For

Unexpected costs are common in knob and tube replacement projects, particularly when your electrician uncovers hidden issues inside the walls. Keep the following add-on cost factors in mind when reviewing your project estimate.

Repairs

After knob and tube replacement, you will likely need to patch or repair the walls that were opened during the electrical work, with costs varying based on your home's wall material. Drywall patches and repairs run $60 to $900, or $50 to $150 per square foot, while lath and plaster repairs average $80 to $200 per square foot.

Cleanup and Disposal

Cleanup and disposal after knob and tube replacement typically costs $300 to $500, depending on whether your electrician or contractor hauls the debris away or opts to rent a dumpster.

Upgrading Outlets, Switches, and Light Fixtures

Modernizing your electrical system often means upgrading the outlets, switches, and light fixtures that the old knob and tube wiring once powered, since that system is ungrounded and rated for only 60 amps rather than the 100-amp standard required by most modern appliances and electronics. The National Electrical Code also requires an outlet or receptacle at least every 12 feet in each room, so you may need to add outlets to bring your home up to code. Costs for common rewiring upgrades vary by item type, as shown in the table below.

Tips to Reduce the Cost of Knob and Tube Wiring Replacement

Although you don’t want to cut corners when replacing knob and tube wiring with a more modern electrical system, you can save money in a couple other ways. While professional electricians need to handle the main job of the replacement, you can cut down on costs by completing some of the pre- and post-work tasks.

• Choose less expensive fixtures: Since you’ll likely need to replace light and outlet fixtures, you can reduce costs by opting for less expensive models.

• Patch the drywall or plaster yourself: If you need to restore your drywall after the electrician opens the walls during the replacement process, attempt a DIY drywall repair to save on labor costs.

• Touch up the paint yourself: Like the drywall repair, you can likely touch up the ceiling paint and walls on your own post-wiring replacement. 

• Clean up debris yourself: Instead of paying extra for the pros to clean up the debris from the knob and tube replacement, take care of it yourself. For major jobs, consider using a junk removal service, costing an average of $240.

Why You Should Hire a Professional Electrician

When it comes to electrical work in your home, it’s always best to hire a licensed electrician near you. From electrocution to fire hazards, there’s simply too much risk involved if you don’t have the proper know-how. 

Here’s why it’s ideal to hire a professional electrician

Replacing your knob and tube wiring is a dangerous and difficult task, so it’s best to hire a pro for the following reasons:

• A professional has the tools, knowledge, and experience to safely replace knob and tube wiring.

• Licensed electricians will secure the necessary permits and schedule inspections.

• Electricians can accomplish the job more quickly and safely than a homeowner attempting to do it themselves.

• DIY mistakes can result in electrocution, fires, or extensive damage to your home’s electrical system.

• Professional work ensures your home is up to code, which helps prevent insurance issues.

• Electricians can identify any related problems with your electrical system.

How Angi Gets Its Cost Data

Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We extensively research project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We rely on reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects. 

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