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

While it's an investment, replacing the outdated wiring is crucial for the ongoing safety of your home. Replacing your home’s knob and tube wiring costs an average of $12,000 to $36,600, usually ranging from $10 to $20 per square foot. Your total bill depends on your home size, number of circuits, and the wiring’s accessibility. Knob and tube wiring is not considered safe for home electrical wiring due to its high shock and fire risk, making it essential to replace. Keep in mind that you should never attempt to alter any knob and tube wiring found in your home due to high safety risks. Instead, hire a professional electrician to complete the replacement safely.

Knob and Tube Wiring Replacement Cost Breakdown

Here are a few common costs for replacing a knob and tube electrical system. As with any project, cost factors include job size, materials, labor, permits, accessibility, disposal, and other variables.

Rewiring Cost per Square Foot 

It likely doesn’t come as a surprise that the square footage of your home and the number of rooms will impact the project price. Every room means additional wiring, fixtures, switches, and outlets. Costs average between $10 and $20 per square foot.

Removal of Knob and Tube Wiring System 

Since removing the old knob and tube wiring system requires cutting open the walls and ceilings, especially in an older home with outdated wiring, electricians will usually cut back the old wiring so it’s out of the way to install the new wiring. The rest of the old wiring is left in the walls.

If the electrician recommends removing the old wiring, you can expect additional labor time and disposal costs, depending on accessibility and difficulty. Plus, you’ll need to factor in the cost to repair the drywall or lath, ranging from $300 for small fixes to $900 for major repairs. And don’t forget to budget for the cost to repaint the walls, which averages $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 between $50 and $100 per hour to replace knob and tube wiring in your house, not including the cost of materials. Electricians will often charge per opening (each outlet, fixture, or switch), which is usually a flat rate of about $100 to $350 or more per opening. This charge may include prep to finish and clean-up, or those parts of the job may be added as separate items, depending on the electrician. While labor charges are an additional cost, they are essential as this project isn’t safe to complete without a professional electrician. 

Accessibility

Most knob and tube wiring was installed in homes between the 1880s and the 1940s. If your home currently has knob and tube wiring, it’s likely older, making it more challenging to access and run new wiring. Difficult access to wiring and work spaces will increase the cost. For example, electricians may charge more if your home doesn’t have access to a basement, crawl space, or attic because they’ll likely have to open more walls, leading to more clean-up and repair costs. 

Permits

Expect electrical permit costs to range from $10 to $500. The cost of permits will depend on the size and location of the job. The average cost range is from $100 to $125 per permit. Permits are necessary to replace the wiring in your home. It’s against the law to skip the permit for this type of electrical law, and failure to produce the appropriate permits could result in fines.

Inspections

Before starting your knob and tube replacement work, your electrician will have a local building inspector visit the site to evaluate what needs to be done. After the work is complete, the electrician will have a post-inspection of the final product to make sure their work is up to code. Plan on spending from $100 to $150 per inspection. 

Upgrade the Electrical Panel

Replacing knob and tube wiring typically means upgrading your electrical panel. Upgrading your electrical panel costs between $600 and $4,000 on average. Knob and tube systems usually run through a 60-amp electrical box and can’t support modern appliances designed for the present 100-amp panels. Ranging from 100 amps to 400 amps, the panel you need depends on how much electricity you need to power your home and appliances. Consult your electrician to get a professional opinion on the best electrical panel for your home’s needs.

Additional Knob and Tube Wiring Replacement Cost Factors

It’s almost inevitable that unexpected costs will pop up, especially if your electrician finds surprise issues hidden in your walls. Here are a couple of cost factors to keep in mind as possible add-ons to the original project estimate.

Repairs

As we mentioned above, you’ll likely have to invest in repairing your walls after the knob and tube replacement is complete. Depending on the age and build of the home, you may have drywall or lath and plaster walls that need to be patched or repaired after the electrical work is done. 

Drywall patches and repairs typically cost anywhere from $60 to $900, or $50 to $150 per square foot, depending on the size and number of repairs. Lath and plaster typically costs an average of $80 to $200 per square foot. Once all of the repairs are done, you’ll likely have to paint the walls to cover up any imperfections. Painting a wall costs $2 to $6 per square foot if you hire a pro, but it’s a DIY-friendly task. 

Cleanup and Disposal

After the job is done, your electrician or contractor will have some cleanup and disposal to do. This task typically costs about $300 to $500, depending on whether they haul it away or rent a dumpster. Once the dust settles, you may want to hire a professional cleaning service to refresh your home, which costs between $30 to $50 per hour, depending on the home and job size.

Upgrading Outlets, Switches, and Light Fixtures

Replacing knob and tube wiring systems with more modern electrical systems often involves upgrading the things the system powers, like outlets, switches, and lights. Since a knob and tube wiring system is not grounded and it’s designed for 60 amps, it can’t support most modern appliances and electronics that require a grounded 100-amp electrical system.

Additionally, the National Electrical Code (NEC) requires that each room has an electrical outlet or receptacle at least every 12 feet. It’s likely that you’ll need to install some outlets to bring the electrical in your home up to code. You can expect the following upgrades and additions to cost as follows:

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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