Aluminum wiring in 1970s houses: what insurers actually want

Why do insurers care about aluminum wiring?

Because the risk lives at the connections, and connections are invisible until they fail. Aluminum wire expands and contracts more than copper as it heats and cools, and it oxidizes where copper does not. Over decades, that works terminations loose at outlets and switches. A loose connection builds heat, and heat behind a wall is the failure mode insurers are pricing when they see a house built between roughly 1965 and 1976 on an application.

If your Guelph house went up in that window and the wiring has never been touched, assume aluminum until someone looks. It runs through whole neighbourhoods here, and through plenty of the older housing in Fergus too.

Do I have to rewire the whole house?

Usually not. Insurers in Ontario generally accept two paths. The first is remediation: every connection where aluminum meets a device or a splice gets corrected with connectors rated for the job. The second is a full rewire to copper. Both satisfy the insurer when the paperwork is right, and remediation costs a fraction of a rewire. Where we recommend the full rewire is when the insulation is damaged or the original workmanship is poor, and we will show you exactly what we found before you decide.

What does remediation actually involve?

Every point where aluminum meets a device gets opened and corrected. That means outlets, switches, fixtures and junction boxes, one at a time, with rated connectors or CO/ALR devices at each stop. It is methodical work rather than complicated work, and a typical 1970s house takes a day or two. You lose power room by room while we work, not the whole house for a week.

What paperwork will my insurer accept?

An ESA certificate, almost always. We file the notification with the Electrical Safety Authority before the work starts, and the inspection happens when it is done. The certificate is the document your insurer or broker actually wants to see. We send it to you, and to your broker directly if you like. A receipt or a handshake from a contractor without a licence number does not satisfy anyone, and it should not satisfy you either.

What does it cost?

It depends on the number of connections, so we count before we quote. The look inside starts as a standard service call, from $95 as of June 2026, and you get a firm written price for the remediation after it. That number is broken out clearly enough that you can send the quote itself to your insurer to show the work is booked, which has bought more than one client an extension on a renewal deadline.