Safety Concerns with Knob and Tube
1Insulation Contact
K&T wiring was designed to dissipate heat into open air. Modern blown-in or batt insulation traps heat, creating fire risk. This is the #1 concern with K&T homes.
2Age Deterioration
Rubber insulation from 80-100 years ago becomes brittle, cracks, and falls off, exposing bare copper wire. This creates shock and fire hazards.
3Improper Modifications
Decades of amateur repairs often include improper splices, overloaded circuits, and connections to modern wiring without proper methods.
4Limited Capacity
K&T was designed for 1920s loads - a few lights and a radio. Modern appliances, computers, and HVAC systems far exceed original design capacity.
Replacement Costs (2026)
Partial Replacement
$3,000 - $8,000
- • High-use circuits only
- • Kitchen and bathrooms
- • Areas with insulation
- • Circuits with deterioration
Complete Rewire
$8,000 - $20,000
- • All K&T removed
- • New copper throughout
- • Panel upgrade included
- • Modern grounded outlets
Costs vary based on home size, accessibility (attic/basement access reduces costs), and extent of wall repair needed. A professional assessment provides accurate pricing.
Insurance & Mortgage Implications
Common Insurance Company Positions
- Many insurers refuse to cover homes with active K&T wiring
- Premiums can be 50-100% higher for K&T homes
- Fire claims may be denied if K&T was involved
- FHA/VA loans typically require K&T assessment or replacement
Selling a K&T home? Having a licensed electrician's assessment ready shows buyers the wiring has been evaluated and documents any concerns. This facilitates negotiations and prevents deals from falling through during inspection.
The Replacement Process
- 1
Assessment (Day 1)
Identify all K&T circuits, evaluate panel, plan new circuit layout and access points.
- 2
Permit & Planning
Pull permits, finalize scope, schedule inspections.
- 3
Wiring Installation (3-5 Days)
Run new cables, install boxes, disconnect old circuits, connect new devices.
- 4
Inspections
Rough-in inspection before walls closed, final inspection after completion.
- 5
Restoration
Patch and paint where walls were opened. Most access is through attic/basement to minimize wall damage.
Own an Older Wisconsin Home?
If your home was built before 1950, a K&T assessment can identify issues before they become problems - and provide documentation for insurance and resale. Couillard Electric serves Sheboygan, Ozaukee, and Washington Counties.