In 2021, replacing knob-and-tube wiring in a U.S. home typically cost about $8,000-$15,000 for a full rewire, with larger or difficult projects reaching $20,000 or more. Home size, wall access, regional electrician rates, and whether plaster repairs are included drive the estimate.
| Item | Low | Average | High | Notes |
|---|---|---|---|---|
| Partial replacement | $1,500 | $3,500 | $6,000 | Several circuits or a limited area |
| Whole-home rewire | $8,000 | $12,000 | $20,000+ | Scope and access affect the total |
| Rewiring rate | $4 per sq ft | $6 per sq ft | $10+ per sq ft | Electrical work; wall repairs may be extra |
| Plaster repair | $500 | $1,500 | $4,000+ | Depends on openings and finish quality |
Assumptions: 2021-era U.S. pricing, standard-grade copper wiring, ordinary access, and no major service-panel replacement.
Typical 2021 prices for a full knob-and-tube rewire
A modest 1,000-square-foot home with accessible wiring might cost $8,000-$12,000. A 1,500- to 2,000-square-foot house commonly fell around $12,000-$20,000, while a larger multi-story home or one with finished walls could exceed $25,000. These are project totals, not a guaranteed national rate.
For planning, many owners used roughly $6 per square foot as a starting point, then added for difficult access, repairs, and code-related work. Partial rewiring can be less expensive if the electrician can isolate the affected circuits and the remaining system is safe and permitted to stay in service. A licensed electrician should assess the full installation before pricing a limited scope.
How wire, electrician labor, and wall repair shape the quote
A written estimate should separate electrical work from finish repairs and show what is included. Typical 2021 ranges below are approximate; project size and local rates can shift them.
| Quote component | Typical range | Pricing basis | What it covers |
|---|---|---|---|
| Electrical labor | $50-$100 per hour | $4,000-$12,000 total | Removal, routing, connections, testing |
| Copper cable and devices | $1-$3 per sq ft | $1,000-$4,000 total | New cable, boxes, outlets, switches |
| Panel or circuit work | $500-$2,500 | Per project | Additional breakers or panel changes |
| Permits and inspection | $100-$500 | Per permit or job | Local approvals and inspections |
| Wall opening and repair | $500-$4,000+ | Per project | Access cuts, patching, plaster or paint |
Labor and access often dominate the quote; cable itself is only one part of a whole-home rewire. Confirm whether the electrician includes patching, painting, permit fees, cleanup, and disposal or expects separate contractors to handle them.
Why house size, plaster walls, and circuit count change the price
Square footage is a useful first estimate, but it does not capture how many outlets, fixtures, and circuits need work. A 1,200-square-foot home with open basement and attic access may cost less than a smaller house with finished ceilings, dense plaster, or multiple stories.
Two practical thresholds help explain quote differences. At about 1,500 square feet, a full rewire may require substantially more cable and labor than a 900-square-foot home. If more than 30-40 outlet or switch locations need replacement, device installation and circuit planning can add hundreds to several thousand dollars. Knob-and-tube wiring buried under insulation or concealed behind finished plaster also takes longer to locate and remove.
Ask whether the estimate covers every occupied room, garage, attic, and basement, and whether the contractor will replace all active knob-and-tube circuits. Scope gaps can make a low bid look attractive while leaving costly work for later.
Electrician hours and access determine the work schedule
A small, clearly defined partial replacement may take one or two days. A whole-home rewire often takes several days to two weeks, depending on crew size, access, inspection timing, and how much opening and closing of walls is required. Occupied homes may need staged work to keep essential circuits available.
Labor rates in 2021 commonly ranged from $50-$100 per hour, with higher rates in costly metro areas or for urgent scheduling. A two-person crew working 60-100 combined hours at $65 per hour would generate about $3,900-$6,500 in labor before materials, permits, and repairs. Request expected crew size, billable hours, and a plan for keeping power available during the project.
Regional electrician rates can move the 2021 estimate
Regional differences reflected wages, housing age, permit practices, and contractor demand. Compared with a national midpoint, metropolitan markets in the Northeast and West Coast could run roughly 15%-30% higher. Smaller Midwestern and Southern markets could be around 5%-15% lower, although rural travel charges or limited contractor availability might offset savings.
These percentages are broad comparisons, not fixed adjustments. A high-cost city with easy attic access may still be cheaper than a rural home requiring long travel and extensive plaster removal. Compare bids from electricians familiar with older homes in the same local market.
Added charges for panel upgrades, plaster, and insulation
Some homes need more than new cable. A panel upgrade may add about $1,500-$3,500 in 2021, depending on capacity and service work; correcting grounding or adding circuits may add several hundred dollars or more. Plaster and lath repair can add $500-$4,000+, and repainting may be priced separately.
Insulation deserves special attention because older knob-and-tube wiring may be unsafe when covered by insulation. Removing or changing insulation can add cost, and the appropriate remedy depends on wiring condition and local code. Permit fees vary by jurisdiction, so confirm whether the contractor obtains the permit and schedules inspection. Get separate prices for electrical upgrades and finish work instead of assuming they are included.
Three sample home sizes and their likely rewire totals
Examples help compare quotes, but they assume ordinary access and standard materials. Difficult wall access, a panel replacement, or extensive repairs can raise each total.
| Example | Approximate scope | Estimated total | Typical duration |
|---|---|---|---|
| Small home | 900 sq ft, accessible attic, 50-70 labor hours | $8,000-$11,000 | 4-7 working days |
| Mid-size home | 1,500 sq ft, plaster walls, 80-120 labor hours | $12,000-$20,000 | 1-2 weeks |
| Large older home | 2,200 sq ft, multiple floors, limited access | $20,000-$30,000+ | 2 weeks or longer |
Assumptions: 2021 pricing; totals vary by region, circuit count, panel condition, permits, and repair scope.
Ways to lower the knob-and-tube replacement bill
Have the electrician map active circuits before choosing between partial and complete replacement. A limited project can save money when only a small area is affected and the rest of the system passes inspection, but replacing wiring in stages may mean repeat mobilization and wall repairs. Compare the full staged cost with a whole-home quote.
Collect at least three itemized bids using the same room list and specifications. Schedule non-emergency work in advance, clear access to the attic and basement, and decide whether a separate drywall contractor can repair openings more economically. Avoid paying for unneeded premium devices, but do not skip permits, grounding, or required safety corrections. The most reliable savings come from a clearly defined scope and comparable quotes, not simply selecting the lowest total.