Cost Breakdown for Replacing Knob and Tube Wiring
Project Size: The cost of replacing knob and tube wiring is significantly influenced by the home’s size. For example, costs range from $8,000 to $16,000 for a small home (around 800 square feet) and can escalate to $60,000 for a larger property (3,000 square feet). Additional rooms mean more wiring, outlets, switches, and fixtures. Here’s a breakdown based on square footage:
| Square Footage | Average Rewiring Cost |
| 800 | $8,000–$16,000 |
| 1,000 | $10,000–$20,000 |
| 1,300 | $13,000–$26,000 |
| 1,600 | $16,000–$32,000 |
| 2,000 | $20,000–$40,000 |
| 2,500 | $25,000–$50,000 |
| 3,000 | $30,000–$60,000 |
Removal of Knob and Tube Wiring System: Removing old wiring often involves cutting open walls and ceilings. “Electricians may leave some old wiring inside the walls unless complete removal is requested, which incurs additional labor and disposal costs.” – says Service Trade Pros.
Post-removal wall repairs can range from $300 for minor fixes to $900 for extensive repairs, while repainting the interior typically costs around $1,960.
Materials: Replacing knob and tube wiring requires various materials, such as:
- Electrical Wiring: $0.25 to $2.00 per linear foot for types like NM, UF, and THHN/THWN wires.
- Retrofitted Electrical Boxes: $2 to $6 per box.
- Wire Connectors: Approximately $0.20 each.
Quality materials are vital for ensuring compliance with modern electrical standards.
Labor: Electricians charge between $50 and $100 per hour for labor, with some also charging a flat rate per opening (outlet, fixture, or switch) that averages $100 to $350. Hiring a licensed electrician is essential for safe and compliant work.
Accessibility: Homes built from the 1880s to the 1940s often have limited access to areas like basements and attics, complicating the wiring replacement process and increasing labor costs. Electricians may need to open more walls, leading to higher repair expenses.
Permits: Electrical permits are necessary for safe and legal wiring replacements, costing from $10 to $500 depending on the project’s size and location. On average, homeowners should expect to pay between $100 and $125 per permit to avoid fines and legal issues.
Inspections: Inspections are required before and after the replacement project. A local inspector will assess the initial condition and verify compliance after the work is completed. Each inspection typically costs between $100 and $150.
Upgrade of Electrical Panel: Replacing knob and tube wiring may necessitate upgrading the electrical panel, which can range from $600 to $4,000. Modern homes generally require 100-amp panels or higher to meet electricity demands. Consulting with an electrician is advisable for determining the appropriate panel upgrade.
Additional Factors Influencing Replacement Costs
Repairs: Wall repairs are often necessary after installing new wiring, especially in older homes with drywall or lath and plaster walls. Repair costs can range from $60 to $900, or $50 to $150 per square foot, with lath and plaster repairs averaging between $80 and $200 per square foot.
Cleanup and Disposal: Cleanup and disposal of debris post-installation typically costs between $300 and $500. If a contractor is needed for thorough cleaning, the service may range from $30 to $50 per hour.
Upgrading Outlets, Switches, and Light Fixtures: Modernizing the electrical system often requires upgrading outlets, switches, and light fixtures. Costs can vary significantly based on the item, as shown below:
| Upgrade Item | Installation Cost Per Item |
| GFCI grounded outlet | $10–$25 per outlet |
| New electrical outlet | $140–$300 per outlet |
| Replace existing outlet | $125–$250 per outlet |
| New light switch | $100–$200 per switch |
| Replace existing light switch | $50–$150 per switch |
| Smart outlet | $25–$50 per outlet |
| Light fixture | $160–$950 per fixture |
| Ceiling fan | $150–$360 |
These additional expenses can accumulate quickly, making careful budgeting essential.
Tips for Reducing Knob and Tube Wiring Replacement Costs
- Get Multiple Quotes: Obtain estimates from several licensed electricians to identify a fair price and potential savings.
- Consider Partial Replacement: Instead of a full replacement, consider upgrading critical areas first to reduce immediate costs.
- Do Some Prep Work: Save on labor costs by moving furniture and clearing obstructions before the electrician arrives.
- Hire During Off-Peak Times: Scheduling the replacement during slower periods may lead to lower labor costs.
- Prioritize Accessibility: Ensure that wiring is easily accessible to minimize labor hours.
- Use Energy-Efficient Upgrades: Incorporate energy-efficient fixtures and appliances, leading to long-term savings on energy bills.
- Utilize Financial Assistance Programs: Research available grants, rebates, or low-interest loans for home electrical upgrades to offset costs.
DIY vs. Hiring a Professional
Attempting to replace knob and tube wiring without proper training poses significant risks, including injury or fire hazards. Here’s a comparison:
| Factors | DIY | Hiring a Professional |
| Skill Level Required | Very high; training needed | Licensed and experienced electricians required |
| Safety | High risk of injury/fire | Safe; professionals follow safety standards |
| Legal Concerns | Illegal without permits | Legally compliant with permits and certifications |
Given the complexities and hazards associated with knob and tube wiring, hiring a licensed professional is strongly recommended for a safe and effective replacement process.
Knob and Tube Replacement Cost: Key Considerations and Budgeting Guide
Cost Breakdown for Replacing Knob and Tube Wiring
Project Size: The cost of replacing knob and tube wiring is significantly influenced by the home’s size. For example, costs range from $8,000 to $16,000 for a small home (around 800 square feet) and can escalate to $60,000 for a larger property (3,000 square feet). Additional rooms mean more wiring, outlets, switches, and fixtures. Here’s a breakdown based on square footage:
| Square Footage | Average Rewiring Cost |
| 800 | $8,000–$16,000 |
| 1,000 | $10,000–$20,000 |
| 1,300 | $13,000–$26,000 |
| 1,600 | $16,000–$32,000 |
| 2,000 | $20,000–$40,000 |
| 2,500 | $25,000–$50,000 |
| 3,000 | $30,000–$60,000 |
Removal of Knob and Tube Wiring System: Removing old wiring often involves cutting open walls and ceilings. Electricians may leave some old wiring inside the walls unless complete removal is requested, which incurs additional labor and disposal costs. Post-removal wall repairs can range from $300 for minor fixes to $900 for extensive repairs, while repainting the interior typically costs around $1,960.
Materials
Replacing knob and tube wiring requires various materials, such as:
- Electrical Wiring: $0.25 to $2.00 per linear foot for types like NM, UF, and THHN/THWN wires.
- Retrofitted Electrical Boxes: $2 to $6 per box.
- Wire Connectors: Approximately $0.20 each.
Quality materials are vital for ensuring compliance with modern electrical standards. - Labor: Electricians charge between $50 and $100 per hour for labor, with some also charging a flat rate per opening (outlet, fixture, or switch) that averages $100 to $350. Hiring a licensed electrician is essential for safe and compliant work.
- Accessibility: Homes built from the 1880s to the 1940s often have limited access to areas like basements and attics, complicating the wiring replacement process and increasing labor costs. Electricians may need to open more walls, leading to higher repair expenses.
- Permits: Electrical permits are necessary for safe and legal wiring replacements, costing from $10 to $500 depending on the project’s size and location. On average, homeowners should expect to pay between $100 and $125 per permit to avoid fines and legal issues.
- Inspections: Inspections are required before and after the replacement project. A local inspector will assess the initial condition and verify compliance after the work is completed. Each inspection typically costs between $100 and $150.
- Upgrade of Electrical Panel: Replacing knob and tube wiring may necessitate upgrading the electrical panel, which can range from $600 to $4,000. Modern homes generally require 100-amp panels or higher to meet electricity demands. Consulting with an electrician is advisable for determining the appropriate panel upgrade.
Additional Factors Influencing Replacement Costs
Repairs: Wall repairs are often necessary after installing new wiring, especially in older homes with drywall or lath and plaster walls. Repair costs can range from $60 to $900, or $50 to $150 per square foot, with lath and plaster repairs averaging between $80 and $200 per square foot.
Cleanup and Disposal: Cleanup and disposal of debris post-installation typically costs between $300 and $500. If a contractor is needed for thorough cleaning, the service may range from $30 to $50 per hour.
Upgrading Outlets, Switches, and Light Fixtures: Modernizing the electrical system often requires upgrading outlets, switches, and light fixtures. Costs can vary significantly based on the item, as shown below:
| Upgrade Item | Installation Cost Per Item |
| GFCI grounded outlet | $10–$25 per outlet |
| New electrical outlet | $140–$300 per outlet |
| Replace existing outlet | $125–$250 per outlet |
| New light switch | $100–$200 per switch |
| Replace existing light switch | $50–$150 per switch |
| Smart outlet | $25–$50 per outlet |
| Light fixture | $160–$950 per fixture |
| Ceiling fan | $150–$360 |
