Aluminum & Knob-and-Tube Wiring: Rewire Cost & Will Insurance Drop You?

If your house has aluminum branch wiring, you have three permanent fixes to choose from: replace it with copper, or pigtail every connection with a COPALUM crimp or an AlumiConn connector. A full rewire runs roughly $3,000 to $20,000 (most jobs $6,000 to $12,000). The pigtail repairs are usually cheaper than that, but I could not find a trustworthy published per-connection price, so you need an itemized quote. Insurance is the bigger unknown. It varies by company, so ask before you buy or renew.

Knob-and-tube is a different problem with different costs. A lot of the confusion at the insurance counter comes from mixing the two up.

Two different wiring problems

	Aluminum branch wiring	Knob-and-tube
Era	About 1965 to the mid-1970s	Commonly 1880s to 1940s
What it is	Aluminum conductors in modern plastic-sheathed cable	Older ungrounded wiring with cloth-covered conductors
Main hazard	Connections overheat at outlets, switches and splices	Brittle, worn insulation, no ground, buried in insulation
Typical fix	Copper replacement or pigtail repair at every connection	Replacement

CPSC’s Publication 516 says a copper shortage in the mid-1960s pushed builders to use aluminum for general-purpose 15 and 20 amp circuits, where before it was used only for a few large circuits like dryers and ranges. Homes built before 1965 are unlikely to have it. Waypoint Inspection says knob-and-tube was installed from the 1880s into the 1940s and was ungrounded.

How risky is aluminum wiring?

CPSC reports on a survey by the Franklin Research Institute. Homes built before 1972 and wired with aluminum were 55 times more likely to have one or more outlet connections reach “Fire Hazard Conditions” than homes wired with copper. The survey defined that as a cover plate screw reaching 300 degrees F, sparks coming from the receptacle, or charred material around it. The survey looked only at outlet connections, and it gave no data on aluminum-wired homes built after 1972.

The troubling part is the lack of warning. CPSC says failing aluminum connections seldom give easily detected signs. When they do, the signs are warm cover plates, flickering lights, circuits that do not work, or the smell of burning plastic at an outlet or switch. If you see any of those, have an electrician look at it and do not try the repair yourself.

The three repair options, decoded

CPSC will only recommend repairs with documented evidence that they are safe, effective and permanent. Publication 516 (June 2011) names three:

1. Complete replacement with copper cable. CPSC calls this the best method available but says that for many homes it is impractical or prohibitively expensive. The old aluminum can be abandoned inside the walls.
2. COPALUM. A short copper pigtail is joined to each aluminum wire with a crimped sleeve made by a special power tool. CPSC considers it a safe, permanent repair, and every connection should be repaired, including outlets, switches, fixtures, appliances and junction boxes. Only electricians trained by the manufacturer may install it.
3. AlumiConn. The same pigtail idea using a setscrew connector. CPSC called it the next best option when COPALUM is not available, and said it had performed well in early tests but was too new to have a long record.

Plumbline Services, an electrical contractor, describes AlumiConn as equally safe and less expensive. That is the company’s view, and CPSC’s 2011 statement was more cautious, so ask the electrician which method they use and why.

What does not count as a fix: CPSC says twist-on connectors are inadequate, and it strongly recommends against other crimp connectors sold at stores, because none has been evaluated for joining copper and aluminum. If you have to replace a switch or outlet before a permanent repair, CPSC’s older guidance says to use devices marked CO/ALR on the mounting strap.

What the work costs

The published cost numbers I could verify are for whole-house rewires. Amerisave’s 2026 guide gives these:

Home size	Whole-house rewire
About 1,000 sq ft	$4,000 to $9,000
About 1,500 sq ft	$6,000 to $13,000
About 2,000 sq ft	$6,000 to $20,000
About 2,500 sq ft	$10,000 to $25,000
About 3,000 sq ft	$12,000 to $27,000

The guide also gives per-square-foot figures: roughly $2 to $4 in open, accessible framing and $5 to $17 in older homes with closed walls and code upgrades. Add-ons are common:

• Panel replacement: $850 to $2,500
• Drywall repair: $300 to $1,500 per patch, and $2 to $6 per sq ft where whole walls or ceilings are replaced
• Opening and patching walls can add a quarter to a third to the total project cost

For knob-and-tube, Amerisave lists full replacement at about $12,000 to $35,000. Waypoint Inspection’s article gives $3,500 to $8,000 as an average with no year attached. The gap between those two is wide, so I would weigh the 2026 figure more heavily for a typical house.

For COPALUM and AlumiConn repairs, the electrician’s own pricing pages I read gave no dollar ranges. A. J. Long Electric lists a $195 charge for the first 30 minutes of diagnostics and repairs and a $99 dispatch fee in some cases, and says the price depends on the number and accessibility of connections. The honest approach is to ask for a count of connections and a price per connection.

A worked example

A 1,500 sq ft house with aluminum wiring and plaster walls.

• Amerisave’s 1,500 sq ft range: $6,000 to $13,000
• Plus a panel replacement: $850 to $2,500
• Subtotal: $6,850 to $15,500
• If the opening and patching is not already in the quote, add a quarter to a third: $15,500 x 1.33 = about $20,700 at the top

Compare that with the per-square-foot route. At the open-framing rate of $2 to $4, 1,500 sq ft is $3,000 to $6,000. At the closed-wall rate of $5 to $17 it is $7,500 to $25,500. Your attic and basement access decide which end you are on.

Now compare with pigtail repair. If an electrician counts N connections, the price is N times the per-connection rate, plus any panel or permit work. Ask for that rate in writing, along with whether it includes switches, fixtures and appliance connections, since CPSC says all of them need repair.

Will insurance drop you?

I could not find a source that breaks this down by state, and the sources I read say it varies by company. Here is what they do say.

Policygenius (updated October 2023) says most standard insurance companies refuse to insure homes with aluminum wiring. Surplus lines insurers may cover them, typically at a much higher price and with weaker coverage. If the wiring looks worn or hazardous, the insurer may require repairs or drop the policy after its inspection. For knob-and-tube, it says some companies charge higher rates or deny coverage.

MyChoice, a Canadian insurance broker, describes three typical approaches for knob-and-tube: decline, insure after an inspection by a licensed electrical contractor, or write a time-limited policy while updates are made. It stresses that agreeing to insure a home does not mean paying to replace the wiring later. Canadian rules differ from U.S. rules, so use it as a picture of how insurers think, not as a U.S. guide.

A. J. Long Electric states it plainly: only the insurer, lender, buyer or inspector can decide what it will accept. The company provides documentation of the work but does not promise how a third party reacts.

How agents and sellers confuse the terms

Some of the mix-ups that cause real trouble:

• Aluminum wiring vs copper-clad aluminum. CPSC says cable marked CU-clad or copper-clad uses copper-coated aluminum wire and is not covered by its repair recommendations.
• Branch circuit wiring vs service wires. CPSC notes that the repairs it describes do not apply to the larger aluminum wires used for service entrance cables, electric dryers and ranges.
• Aluminum vs knob-and-tube. A form that asks about “old wiring” lumps them together, and an insurer that declines one may accept the other.
• Remediation vs rewire. A pigtail repair keeps the existing aluminum wire in the walls and is not a rewire. Some insurers accept it and some insist on copper. Ask which one they require by name.
• Active vs abandoned. MyChoice says not to label old wiring inactive unless a qualified electrical contractor verifies it is disconnected from every source.

Knob-and-tube has one more hazard worth knowing. ENERGY STAR warns that pre-1930 knob-and-tube wiring can be a fire hazard in contact with insulation, and Waypoint Inspection says the 2008 National Electrical Code states it should not be located in hollow spaces insulated with loose, rolled or foamed-in-place material. Check before you blow new insulation into the attic.

What to ask the insurer

1. Do you write policies on homes with aluminum branch wiring (or knob-and-tube)? Standard market or surplus lines?
2. Do you require an electrician’s inspection first? Who can do it?
3. Which repairs do you accept: copper replacement, COPALUM, AlumiConn?
4. If I repair it, will the premium change? Please confirm in writing.
5. How long do I have to complete repairs after binding the policy?

Keep the written answers and the electrician’s paperwork together. MyChoice recommends keeping the assessment, invoices, proof of payment and photos taken before walls are closed.

What to do next

1. Confirm what you have. Look at the cable jacket in the basement or attic for “Al” or “Aluminum” markings, as CPSC describes, or hire an electrician to verify.
2. Do not DIY the repair. CPSC warns against it.
3. Get two written quotes, one for COPALUM or AlumiConn pigtailing with a connection count, and one for full copper replacement.
4. Call your insurer, or shop for coverage before closing if you are buying.
5. Use the Wire Size Calculator and the Breaker Size Calculator to check what a rewire needs for each circuit.
6. If you are buying, ask the seller to repair before closing. Policygenius says that can significantly lower rates.

Sources

• U.S. Consumer Product Safety Commission, Publication 516: Repairing Aluminum Wiring (June 2011)
• CPSC, Safety Recommendations for Aluminum Wiring in Homes (1974 release)
• Policygenius, Does Homeowners Insurance Cover Aluminum Wiring? (updated October 2023)
• Amerisave, What It Costs to Rewire a House (2026)
• MyChoice, A Guide to Knob and Tube Wiring and Insurance (Canada)
• Waypoint Inspection, Knob and Tube Wiring
• Plumbline Services, Repair or Replace Aluminum Wiring
• A. J. Long Electric, Aluminum Wiring
• ENERGY STAR, Attic Insulation Project