Knob and Tube Wiring Replacement Cost: Easy 2026

Knob and tube wiring replacement cost in Michigan typically runs $12,000 to $25,000, with most 1,500 to 2,000 square foot homes landing between $12,000 and $18,000. If you’re reading this, there’s a good chance an insurance company, a home inspector, or a buyer just made knob and tube wiring your problem — and you need a real number. This guide gives you honest 2026 pricing for Metro Detroit, explains what drives it, and covers the insurance reality that makes this project urgent for many homeowners.

IB Electric replaces knob and tube wiring across Wayne, Oakland, and Macomb counties, and our founder has held a Michigan master electrician license since 1997. Metro Detroit’s older neighborhoods have plenty of it, and we handle these projects — including the panel and insurance angles — regularly. Here’s what to expect.

What Is the Knob and Tube Wiring Replacement Cost?

For a full replacement, knob and tube wiring replacement cost generally runs $8 to $17 per square foot, putting most homes in the $12,000 to $25,000 range. It costs more than a standard rewire because there’s no partial fix — the entire old, ungrounded system has to be replaced with modern grounded wiring throughout the house. Home size is the main driver, and the table shows realistic ranges by size for a Michigan home.

These assume reasonable access. Because knob and tube is found in older homes — often with plaster walls and limited access — many real-world projects land at the higher end. For the broader picture on rewiring in general, our guide to the whole house rewiring cost in Michigan covers standard rewires too.

Why It Costs More Than a Standard Rewire

Knob and tube replacement sits at the higher end of rewiring projects for specific reasons, and understanding them explains the quote you’ll receive.

• The whole system must go. Knob and tube has no ground wire, so there’s no way to partially upgrade it safely. Every run gets replaced with new grounded wiring throughout the home.
• Old homes, harder access. Knob and tube is found in homes from roughly the early 1900s to the 1940s, which usually means plaster walls and finished spaces that are more labor-intensive to open and repair than modern drywall.
• A panel upgrade is often needed. These homes frequently have outdated panels or fuse boxes, so the project commonly includes a service upgrade, proper grounding, and modern AFCI/GFCI protection.
• New outlets and grounding everywhere. Replacing an ungrounded system means new grounded outlets throughout, brought up to current code.

Pro tip: Ask whether the quote is to fully remove the old knob and tube or to de-energize and abandon it in the walls. Electricians often safely disconnect and leave the old wiring in place rather than extract it, because full removal adds labor and disposal cost. Neither is wrong, but knowing which you’re quoted explains a price difference between two bids.

The Insurance Reality Behind This Search

For most homeowners, knob and tube replacement isn’t prompted by a safety scare — it’s prompted by a letter. Here’s the reality worth understanding. Knob and tube wiring often isn’t illegal, and many codes allow it to stay in place if it’s intact and unmodified. The pressure comes from insurers, lenders, and buyers. Many insurance carriers now refuse to write new policies, or won’t renew existing ones, on homes with knob and tube wiring — and in some cases coverage is simply unavailable. At sale, a buyer’s lender or inspector flags it, often making replacement a condition of the deal, and homes with knob and tube can see their value drop meaningfully and their buyer pool shrink.

That’s why this is frequently a time-sensitive project rather than a someday one. If you’ve received a non-renewal notice or you’re preparing to sell, you’re on a clock set by your carrier or your closing date. The good news is that replacement resolves it cleanly: once the knob and tube is gone and the work passes inspection, the insurance and resale obstacles go with it. It’s a similar dynamic to outdated panels — our guides on Federal Pacific panel replacement and fuse box to breaker replacement cover those insurance-driven fixes too.

What Drives Your Final Price

Within the ranges above, a few factors decide where your home lands:

• Accessibility. The single biggest swing. Open basements and attics keep costs down; plaster walls and finished, hard-to-reach spaces raise them.
• Home size and number of circuits. More square footage and more rooms mean more wire, outlets, and labor.
• Full removal vs abandonment. Extracting the old wiring costs more than safely de-energizing and leaving it; your quote should specify which.
• Panel upgrade. Often bundled in, since these homes usually need modern service and grounding — see the cost to replace an electrical panel.
• Wall repair and finishes. Patching plaster or drywall, painting, and cleanup — often quoted separately.
• Permits and inspection. Required for this work in Michigan, typically a few hundred dollars.

Costs Base Quotes Often Leave Out

As with any rewire, the headline number can hide real costs. Budget for these so your quotes are comparable:

• Wall and ceiling repair. Fishing new wire means holes to patch; plaster repair in older homes runs more than drywall.
• A panel upgrade. If the service can’t support modern grounded wiring, this gets added — often several thousand dollars.
• Painting and cleanup. After patching comes repainting and debris removal.
• Temporary relocation. For a whole-home job, many electricians recommend staying elsewhere during the work.

A sensible approach is to budget 15 to 25% above a base estimate and insist on an itemized quote. That’s the only way to know whether one bid is truly cheaper or just leaves more out.

Is Replacement Worth It?

For knob and tube, replacement is almost always worth it — and often not optional. Beyond resolving the insurance and resale obstacles, it removes a genuine safety concern: the ungrounded, aging system is a shock and fire risk, especially when paired with modern high-draw appliances or when insulation has been added around old wiring. Replacement brings your home up to current code, adds grounded outlets throughout, and finally supports today’s electrical loads. Given the fire risk, the insurance pressure, and the resale impact, it’s one of the higher-value investments an older home can make — and the sooner it’s handled, the sooner those risks and pressures disappear. You can review electrical fire-safety guidance from the Electrical Safety Foundation International, and since this is permitted work, Michigan’s process is on the LARA permit page.

Conclusion

Knob and tube wiring replacement cost in Michigan comes to $12,000 to $25,000 for most homes, driven by size, access, and whether a panel upgrade is included — with older Metro Detroit homes often landing higher due to plaster walls. But for most homeowners the number matters less than the deadline: this is usually an insurance- or sale-driven project on a clock. Get an itemized quote, budget a cushion for wall repair and a possible panel upgrade, and handle it before your carrier or closing forces the timeline. Once it’s done, the safety risk and the insurance headache are both gone for good.