Solid aluminum wiring used for branch circuits (the outlets and switches) in many homes built roughly 1965–1973, when copper prices spiked. Aluminum expands, contracts, and oxidises differently than copper, so terminations can loosen and overheat over time. (This is about branch wiring; large-gauge aluminum service entrance and feeder cable is normal and not the same concern.)
$300–1,500 to remediate (pigtail/COPALUM/AlumiConn); more for a rewireAddress before purchaseElectrical
Why it matters
It's a recognised fire risk at the connections. A U.S. Consumer Product Safety Commission–funded study found homes wired with aluminum before 1972 were about 55 times more likely to have a connection reach "fire-hazard conditions" than copper-wired homes, and aluminum terminations have been known to fail without any prior warning signs. It can also be an insurance flag. The good news: it rarely needs a full rewire — properly done remediation makes it acceptable. In Ontario, ESA notes aluminum wiring is safe when connected and terminated to the Electrical Safety Code and the device manufacturer's instructions.
How to spot it
A 1965–1973 build; "AL" or "ALUMINUM" stamped on the cable sheathing at the panel or in the attic/basement; warm or discoloured switch/outlet cover plates; flickering lights not traced to a fixture or appliance; a faint burning-plastic smell at a device.
What it costs
Often $300–1,500 to remediate connections with approved methods — copper "pigtailing" with listed connectors, or COPALUM/AlumiConn crimps by a qualified electrician. A full rewire costs far more but is rarely necessary.
What to do
Address before purchase. ESA recommends a Licensed Electrical Contractor familiar with aluminum-wiring techniques assess it, do the repairs, and have the work inspected — and not to wait for signs of overheating, since failures can be silent. Confirm coverage with your insurer/broker before removing conditions.
Education and triage, not a home inspection. Casaroo flags aluminum-wiring risk from the era and visible cable markings — a licensed electrician confirms the connections and remediates them.
Common questions
What is Aluminum branch wiring?
Solid aluminum wiring used for branch circuits (the outlets and switches) in many homes built roughly 1965–1973, when copper prices spiked. Aluminum expands, contracts, and oxidises differently than copper, so terminations can loosen and overheat over time. (This is about branch wiring; large-gauge aluminum service entrance and feeder cable is normal and not the same concern.)
Why does it matter for home buyers?
It's a recognised fire risk at the connections. A U.S. Consumer Product Safety Commission–funded study found homes wired with aluminum before 1972 were about 55 times more likely to have a connection reach "fire-hazard conditions" than copper-wired homes, and aluminum terminations have been known to fail without any prior warning signs. It can also be an insurance flag. The good news: it rarely needs a full rewire — properly done remediation makes it acceptable. In Ontario, ESA notes aluminum wiring is safe when connected and terminated to the Electrical Safety Code and the device manufacturer's instructions.
How can I spot it?
A 1965–1973 build; "AL" or "ALUMINUM" stamped on the cable sheathing at the panel or in the attic/basement; warm or discoloured switch/outlet cover plates; flickering lights not traced to a fixture or appliance; a faint burning-plastic smell at a device.
How much does it cost to fix?
Often $300–1,500 to remediate connections with approved methods — copper "pigtailing" with listed connectors, or COPALUM/AlumiConn crimps by a qualified electrician. A full rewire costs far more but is rarely necessary.
A licensed electrician confirms and repairs; Casaroo flags, it does not inspect.
Last reviewed 2026-06-27.
Casaroo reviews each guide against current pricing, code, and insurer practice. Cost ranges are 2026
estimates that vary by region, size, and access — confirm specifics with a licensed professional.