Aluminum Wiring: The 1965 to 1973 Homes, State by State

Aluminum wiring entered homes on a copper shortage and lost favor with a 1972 alloy change

Federal and industry records place aluminum branch wiring in a short window. CPSC says homes built before 1965 are unlikely to have it, and USGS price data show copper climbing 79.5% from 1964 to 1970 while aluminum barely moved.

The U.S. Consumer Product Safety Commission (Publication 516, June 2011) says a copper shortage in the mid 1960s pushed builders to run aluminum wire on general purpose 15 and 20 amp circuits, not only on the large dryer and range circuits where it was already common. CPSC adds that homes built before 1965 are unlikely to have aluminum branch circuit wiring, and that cables installed from 1965 to the mid 1970s, in new homes, additions and rewired circuits, may contain it.

USGS historical statistics show the price gap that made the switch attractive. The US copper unit value rose from $713 a metric ton in 1964 to $1,280 in 1970, while aluminum went from $522 to $633 (USGS copper statistics; USGS aluminum statistics). Copper cost 1.37 times as much as aluminum per ton in 1964, 2.02 times in 1970 and 2.25 times in 1973. US copper stocks fell from 1,200,000 metric tons in 1960 to 342,000 in 1969, a 71.5% drop.

The window closed through product standards rather than a ban. NEMA (2012 white paper) dates the industry reevaluation program to 1970 and says that by mid-1972 only requalified aluminum conductors and CO/ALR wiring devices were acceptable under industry standards. IAEI (January/February 2006) says AA-8000 series alloy wire was listed and manufactured beginning in 1972. The National Electrical Code first named AA-8000 conductors specifically in its 1987 edition.

Branch circuit aluminum wiring: Solid aluminum conductors, sized No. 10 and No. 12 AWG, feeding outlets, switches and fixtures on 15 and 20 amp circuits. CPSC's repair guidance does not cover the larger aluminum service entrance, dryer and range cables, or copper-clad aluminum wire.

CPSC's 55-times finding covers outlets in homes built before 1972

The most cited federal number comes from a Franklin Research Institute survey done for CPSC. It measures outlet connections only, and it stops at 1972.

CPSC reports that the national Franklin Research Institute survey found homes built before 1972 and wired with aluminum were 55 times more likely than copper-wired homes to have one or more outlet connections reach Fire Hazard Conditions (CPSC Publication 516). The survey defined that condition as a receptacle cover plate screw reaching 149 degrees C (300 degrees F), sparks from the receptacle, or charring of nearby materials.

• The survey covered wire connections at outlets only; CPSC notes that other aluminum connections and splices are also prone to fail.
• CPSC says no information was developed for aluminum-wired homes built after 1972.
• On April 28, 1974, two people died in a Hampton Bays, New York, house fire that fire officials traced to an overheating aluminum connection at a wall receptacle, according to CPSC.
• CPSC says failing aluminum connections seldom give warning signs; the signs it lists are hot face plates, flickering lights, dead circuits and a burning plastic smell.

Laboratory work at the National Bureau of Standards (Journal of Research, 1980) explains the mechanism. In a loose connection, arcing at the iron screw and aluminum wire interface produced temperatures in excess of 1,500 degrees C and formed intermetallic compounds with high resistivity. A tight receptacle connection carrying 15 amps dissipates on the order of 80 milliwatts; a glowing connection has been reported at up to 36 watts.

15.8 million surviving homes date from the 1965 to 1973 window

Splitting the Census 2025 decade counts by the timing of regional housing starts puts 15.8 million homes, 10.7% of all US housing units, in the 1965 to 1973 build years. This is an era estimate, not a count of homes that have aluminum wiring.

The 2025 American Community Survey counts 14.0 million housing units built from 1960 to 1969 and 20.1 million built from 1970 to 1979 (ACS 2025 1-year, B25034). Census does not publish single years, so KBR weighted each decade by the share of that decade's private housing starts that fell inside the window, region by region (Census New Residential Construction). Nationally, 1965 to 1969 held 0.491 of 1960s starts and 1970 to 1973 held 0.446 of 1970s starts.

California has the most era homes, an estimated 1.8 million, followed by Texas (1.2 million), Florida (1.1 million), New York (917,223) and Illinois (643,887). Those five states hold 35.8% of the national estimate.

Among owner-occupied homes, the estimate is 9.1 million, or 10.42% of owner-occupied units (ACS B25036). Of occupied homes built from 1960 to 1979, 68.0% are in one-unit structures and 4.42% are mobile homes, boats, RVs or vans (ACS B25127).

Hawaii, Louisiana and Oklahoma have the largest era shares; Nevada the smallest

Ranking by share rather than count moves smaller states to the top. Fast-growing Sun Belt and Mountain states sit at the bottom because most of their housing is newer.

An estimated 14.6% of Hawaii's housing units date from 1965 to 1973, the highest share of any state. Louisiana and Oklahoma follow at 13.34% each, then Connecticut at 12.74%. Nevada has the smallest share at 6.53%, behind the District of Columbia (6.92%) and Utah (7.66%).

Texas ranks second by count but 40th by share (9.34%), because so much of its housing was built after 1980. Michigan is the only state in the top 10 on both lists, with 568,381 era homes and a 12.11% share.

The window holds three of the four biggest years for US housing starts

The aluminum years were also boom years. Private starts reached a record 2.36 million in 1972, so the 1970s weight leans toward the window's end.

Census annual starts, a series that begins in 1959, peak at 2,357 thousand units in 1972. The next three years are 2005 (2,068 thousand), 1971 (2,052 thousand) and 1973 (2,045 thousand), so 3 of the four highest years fall inside the 1965 to 1973 window (Census starts by region). Private starts across the nine window years total 14,791 thousand units.

The Northeast's 1970s weight (0.502) is the highest of the four regions because its building fell off after 1973; the Midwest's (0.414) is the lowest because its starts stayed strong through 1978.

CPSC accepts three permanent repairs and calls CO/ALR devices an incomplete fix

CPSC's 2011 guidance names one replacement method and two pigtail connectors as permanent. Twist-on pigtails and CO/ALR devices are, in CPSC staff's view, temporary at best.

The Commission voted unanimously, 5 to 0, on a ballot due March 21, 2011, to republish Publication 516 with explicit recognition that COPALUM and AlumiConn connectors were the only products meeting the agency's standards (CPSC Record of Commission Action). The publication sets three tests: a repair must be safe, effective and permanent.

CPSC calls full copper replacement the best method but says it is impractical or prohibitively expensive in many homes. COPALUM uses a dedicated power tool whose dies apply upwards of 10,000 pounds of force, and only manufacturer-trained electricians may install it. CPSC describes AlumiConn, a setscrew connector, as the next best alternative when COPALUM is not available.

Four of nine Maine insurer filings name aluminum wiring; Texas and Louisiana sale forms ask about it

Insurer rules range from outright ineligibility to acceptance with an electrician's certificate. Two of three state sale disclosure forms we checked name aluminum wiring.

Of nine homeowners underwriting guideline files posted by the Maine Bureau of Insurance, four name aluminum wiring (4 of 9 (44.4%)). Hanover (2018) and both Integon National files (2019; undated) list it as making a home ineligible. State Farm (effective 2023) excludes single strand aluminum wiring unless a licensed electrician certifies that every connection was repaired with methods approved by CPSC.

In Florida, the Citizens Property Insurance 4-point inspection form (Insp4pt 01 18) asks the inspector to flag branch circuit aluminum wiring and to say whether connections were repaired with a COPALUM crimp or AlumiConn, with remediation certified by a licensed electrician.

Texas's seller's disclosure notice, effective May 28, 2026, lists Aluminum Wiring among the conditions a seller must say whether they are aware of (TREC No. 55-1). Louisiana's January 2026 property disclosure document asks: Are you aware of any aluminum wiring in the structure? (LREC). Washington's statutory form asks about defects in the electrical system, including wiring, without naming aluminum (RCW 64.06.020). Texas and Louisiana together hold an estimated 1,487,423 era homes.

Ending the window in 1972 or 1975 moves the count by 2.3 to 2.8 million homes

The weights matter less than the window. Swapping starts for completions changes the total by 2.8% and one national weight pair by 0.1%; ending the window in 1972 or 1975 changes it by 14.7% or 17.9%.

The main estimate is 1.07 times the private starts recorded for 1965 to 1973. A ratio above 1 is a warning sign: the ACS counts mobile homes and public housing that private starts omit, and households tend to round year built to a decade. Removing the mobile-home share cuts the ratio to 1.02. Read 15.8 million as an upper-leaning era figure.

Dishwashers, light fixtures and junction boxes are on CPSC's repair list too

CPSC's repair scope reaches beyond outlets and switches to permanently connected appliances, which is where kitchen and bathroom projects meet the old wiring.

CPSC says every aluminum connection or splice should be repaired, including outlets, dimmers, switches, fixtures, appliances and junction boxes, and names dishwashers, heaters, air conditioners and light fixtures wired directly to No. 10 or No. 12 aluminum circuits. CPSC also says all modifications to installed wiring should be performed and inspected under local rules.

For a homeowner planning a remodel in a 1965 to 1973 house, those points mean the electrical scope and permit can affect schedule; our kitchen remodel timeline and guide to choosing a remodeling contractor cover how to plan those steps. Related old-house hazards are covered in our reports on knob and tube wiring, Federal Pacific panels, polybutylene pipe and Chinese drywall.

Dated official positions on aluminum branch wiring

Checked at each report refresh (planned yearly with the ACS 1-year release). Last checked 2026-11-08. Entries are neutral records of public data; each links to its source record.

State-by-state findings

1. An estimated 15.8 million US housing units built 1965 to 1973 were standing in 2025, 10.7% of 148.2 million units.^[1][5]
2. Owner-occupied era homes number an estimated 9.1 million, 10.42% of US owner-occupied units in 2025.^[2][5]
3. California leads by count with an estimated 1,765,484 era homes in 2025, followed by Texas (1,199,640) and Florida (1,149,072).^[1][5]
4. Hawaii has the highest era share in 2025 at 14.6%; Louisiana and Oklahoma follow at 13.34%.^[1][5]
5. Nevada has the lowest era share in 2025 at 6.53%, then DC (6.92%) and Utah (7.66%).^[1][5]
6. Five states, California, Texas, Florida, New York and Illinois, hold 35.8% of the US era estimate.^[1][5]
7. US private housing starts hit a record 2,356.6 thousand in 1972; 3 of the 4 highest years since 1959 fall in 1965 to 1973.^[5]
8. CPSC: homes built before 1972 with aluminum wiring were 55 times more likely to have outlet connections reach Fire Hazard Conditions than copper-wired homes.^[7]
9. CPSC defines Fire Hazard Conditions as a cover plate screw at 149 degrees C (300 degrees F), sparks, or charring.^[7]
10. National Bureau of Standards tests in 1980 found arcing temperatures above 1,500 degrees C at loose iron screw and aluminum wire interfaces.^[9]
11. The CPSC Commission voted 5 to 0 in March 2011 to republish Publication 516 recognizing only COPALUM and AlumiConn connectors.^[8]
12. US copper unit value rose 79.5% from 1964 to 1970, while US copper stocks fell 71.5% from 1960 to 1969.^[10]
13. State Farm's 2023 Maine guidelines accept solid aluminum wiring only with an electrician's certificate of CPSC-approved repairs.^[13]
14. Texas (May 2026) and Louisiana (January 2026) seller disclosure forms ask about aluminum wiring by name; Washington's does not.^[22][23][24]

Rankings and ratios we derived

Download the calculations (CSV)

Executive summary

• KBR estimates 15.8 million US housing units standing in 2025 were built from 1965 to 1973, 10.7% of the stock; the figure marks the aluminum wiring era, not homes confirmed to have it.
• California has the most era homes (1.8 million); Hawaii has the highest share (14.6%) and Nevada the lowest (6.53%).
• CPSC reports that pre-1972 aluminum-wired homes were 55 times more likely than copper-wired homes to have outlet connections reach Fire Hazard Conditions.
• CPSC accepts three permanent repairs: copper rewiring, COPALUM crimps and AlumiConn connectors; it treats twist-on pigtails and CO/ALR devices as temporary.
• Copper cost 1.37 times as much as aluminum per ton in 1964 and 2.02 times in 1970, per USGS unit values.
• Four of nine Maine insurer guideline files name aluminum wiring; Texas and Louisiana seller disclosure forms ask about it by name.
• Ending the window in 1972 or 1975 instead of 1973 moves the estimate to 13.5 million or 18.7 million.

Frequently asked questions

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Reproduce this analysis

Every figure comes from the files below. The scripts that pulled and computed them are kept with the report and can be re-run.

Data quality and exclusions

• Puerto Rico removed from the ACS state rows (1 row); the analysis covers 50 states and DC (51 rows).
• Wyoming has no 2025 1-year B25127 row, so state-level mobile-home adjustments were not used; the national adjustment uses the US row only.
• Census completions by region start in 1968; they were used only to test the 1970s weight (table t6), not for the 1960s.
• Two copies of CPSC Publication 516 were opened (cpsc.gov/s3fs-public/516.pdf and /pdfs/516.pdf); their text matched apart from hyphenation, and the first is cited.
• One unsourced per-device COPALUM price on a home inspection page was dropped because it named no source (see excluded.md).

Methodology

Source selection: federal agencies first (Census, CPSC, National Bureau of Standards, USGS), then state agency forms and insurer filings, then two trade bodies (IAEI, NEMA) for product standard history. Commercial blogs and contractor pages were read only as pages to beat.

Era estimate: ACS 2025 1-year table B25034 gives housing units by decade built for 50 states and DC. Each state's 1960s count was multiplied by its Census region's share of 1960s private starts that fell in 1965 to 1969, and its 1970s count by the share of 1970s starts in 1970 to 1973. Starts were used because Census completions by region begin only in 1968.

Owner-occupied and structure-type figures use B25036 and B25127 from the same release. B25127 is not published for Wyoming in the 2025 1-year file, so structure shares are used only at the national level.

Conflicts: CPSC gives two bounds, before 1972 for its survey and the mid 1970s for installation; the brief's 1965 to 1973 window sits between them, and table t6 shows the 1965 to 1972 and 1965 to 1975 alternatives. Insurer files were coded once each by searching the full text for 'aluminum'.

Limitations: no federal survey asks what metal a home's wiring is, so no state count of aluminum-wired homes exists. ACS year built is self-reported. Maine insurer files are dated filings that may have been replaced.

Last updated 2026-11-08. ACS 2025 1-year data were released 2026-10-29.

This report presents published data with its limitations. It is not legal, financial or investment advice.

Sources, ranked by quality

Tier 1: primary and official sources (24)

• [1] U.S. Census Bureau. American Community Survey 2025 1-year, Table B25034 Year Structure Built. 2025. Accessed 2026-11-08.
• [2] U.S. Census Bureau. American Community Survey 2025 1-year, Table B25036 Tenure by Year Structure Built. 2025. Accessed 2026-11-08.
• [3] U.S. Census Bureau. American Community Survey 2025 1-year, Table B25127 Tenure by Year Built by Units in Structure. 2025. Accessed 2026-11-08.
• [4] U.S. Census Bureau. 2025 ACS Data Release Schedule. 2025 ACS releases. Accessed 2026-11-08.
• [5] U.S. Census Bureau. New Residential Construction: New Privately-Owned Housing Units Started, annual by region. 1959 to 2025. Accessed 2026-11-08.
• [6] U.S. Census Bureau. New Residential Construction: New Privately-Owned Housing Units Completed, annual by region. 1968 to 2025. Accessed 2026-11-08.
• [7] U.S. Consumer Product Safety Commission. Repairing Aluminum Wiring, Publication 516 (June 2011). June 2011. Accessed 2026-11-08.
• [8] U.S. Consumer Product Safety Commission. Record of Commission Action: CPSC Publication No. 516, Repairing Aluminum Wiring (ballot due March 21, 2011). March 2011. Accessed 2026-11-08.
• [9] National Bureau of Standards (now NIST). Observations on the Mechanisms of High Resistance Junction Formation in Aluminum Wire Connections, Journal of Research Vol. 85 No. 6 (1980). 1980. Accessed 2026-11-08.
• [10] U.S. Geological Survey. Copper Statistics, Historical Statistics for Mineral and Material Commodities (Data Series 140), last modified June 27, 2023. 1900 to 2020. Accessed 2026-11-08.
• [11] U.S. Geological Survey. Aluminum Statistics, Historical Statistics for Mineral and Material Commodities (Data Series 140), last modified July 5, 2023. 1900 to 2021. Accessed 2026-11-08.
• [12] Citizens Property Insurance Corporation (Florida). 4-Point Inspection Form, Sample Form Insp4pt 01 18. Form edition 01 18. Accessed 2026-11-08.
• [13] State Farm via Maine Bureau of Insurance (Internet Archive). State Farm Underwriting Guidelines, Homeowners, Maine (effective 1/1/2023); Internet Archive capture of the maine.gov file. Effective January 1, 2023. Accessed 2026-11-08.
• [14] Hanover Insurance Group via Maine Bureau of Insurance (Internet Archive). Hanover, Maine Homeowners Underwriting Guidelines (effective 12/03/2018); Internet Archive capture of the maine.gov file. Effective December 3, 2018. Accessed 2026-11-08.
• [15] Integon National via Maine Bureau of Insurance (Internet Archive). Integon National Insurance Company, Maine Homeowners OneChoice (revised April 25, 2019); Internet Archive capture of the maine.gov file. Revised April 25, 2019. Accessed 2026-11-08.
• [16] Integon National via Maine Bureau of Insurance (Internet Archive). Integon National Insurance Company, Homeowners Guidelines OneChoice and Premier Client, Maine (undated); Internet Archive capture of the maine.gov file. Undated. Accessed 2026-11-08.
• [17] Farmers via Maine Bureau of Insurance (Internet Archive). Farmers Property and Casualty Insurance Company, Maine Homeowner New Business Underwriting Guidelines (October 5, 2021); Internet Archive capture. October 5, 2021. Accessed 2026-11-08.
• [18] Farmers via Maine Bureau of Insurance (Internet Archive). Farmers Casualty Insurance Company (FCAS), Maine Homeowner Underwriting Guidelines; Internet Archive capture. December 9, 2022. Accessed 2026-11-08.
• [19] USAA via Maine Bureau of Insurance (Internet Archive). USAA Group Homeowners Insurance Underwriting Guidelines, Maine (Rev. Eff. 02/24/2023); Internet Archive capture. Effective February 24, 2023. Accessed 2026-11-08.
• [20] Chubb via Maine Bureau of Insurance (Internet Archive). Homeowners Underwriting Guidelines, State: Maine (effective 08/01/2022), Chubb writing companies; Internet Archive capture. Effective August 1, 2022. Accessed 2026-11-08.
• [21] Unnamed insurer via Maine Bureau of Insurance (Internet Archive). Maine Homeowners New Business Eligibility and Pricing Guidelines, form PL-12430 (01-07), insurer not named; Internet Archive capture. Form edition 01-07. Accessed 2026-11-08.
• [22] Texas Real Estate Commission. Seller's Disclosure Notice, TREC No. 55-1 (effective 05/28/2026). Effective May 28, 2026. Accessed 2026-11-08.
• [23] Louisiana Real Estate Commission. Residential Property Disclosure Document (01/2026). January 2026 edition. Accessed 2026-11-08.
• [24] Washington State Legislature. RCW 64.06.020 Improved residential real property, seller's duties, format of disclosure statement. Current statute as accessed. Accessed 2026-11-08.

Tier 2: trade bodies, market research, company data (2)

• [25] International Association of Electrical Inspectors. Aluminum Building Wire Installation and Terminations, IAEI Magazine (January/February 2006). January/February 2006. Accessed 2026-11-08.
• [26] National Electrical Manufacturers Association (Internet Archive). The Evolution of Aluminum Conductors Used for Building Wire and Cable (2012); Internet Archive capture. 2012. Accessed 2026-11-08.