Is it more cost-effective to rewire my entire house or just upgrade specific circuits during a renovation?

Whether to do a full rewire or targeted circuit upgrades depends on the age and condition of your existing wiring, the scope of your renovation, and your budget — but if your home still has knob-and-tube or aluminum wiring, a full rewire during a major renovation is almost always the smarter long-term investment. Walls are already open during renovation, which dramatically reduces the labour cost of rewiring compared to doing it as a standalone project.

If your home was built before 1945 and has original knob-and-tube wiring — common across Toronto's older neighbourhoods like High Park, Leslieville, and Rosedale — a full rewire is the right call whenever you're doing a renovation that opens walls. The cost difference between rewiring with open walls versus closed walls is substantial. Running new NMD90 cable through exposed wall cavities takes a fraction of the time compared to fishing wire through finished walls, cutting access holes, and patching drywall afterward. Many GTA electricians estimate that rewiring during a renovation saves 20 to 40 percent on labour compared to a standalone rewire.

For post-war homes built in the 1950s through 1970s with copper wiring and 100A panels, a targeted approach often makes more sense. If the existing copper wiring is in good condition and properly grounded, there's no compelling reason to rip it all out. Instead, focus your electrical budget on upgrading the circuits that matter most: adding dedicated 20A circuits for the kitchen (modern code requires separate circuits for countertop outlets, refrigerator, and dishwasher), installing GFCI protection in bathrooms and kitchens, adding AFCI breakers on bedroom circuits, and running new circuits for any added loads like an EV charger, hot tub, or home office equipment.

The cost comparison helps frame the decision. A full rewire of a 2,000 square foot home runs $18,000 to $30,000 as a standalone project, but $12,000 to $20,000 when done during a gut renovation with open walls. Adding individual circuits during a renovation typically costs $300 to $800 per circuit. If you only need four or five new circuits and your existing wiring is sound, spending $2,000 to $4,000 on targeted upgrades makes more financial sense than a $20,000 full rewire.

Here's a practical decision framework. Choose a full rewire if your home has knob-and-tube or aluminum wiring, if your panel is 60A, if your insurer is requiring electrical upgrades, or if you're doing a gut renovation that opens most of the walls anyway. Choose targeted circuit upgrades if your existing copper wiring is in good condition, your panel has capacity for additional circuits, and you're only renovating one or two rooms.

Either way, an ESA permit is required for any new circuits or rewiring work in Ontario. Your electrician handles the permit application, and the ESA inspector verifies code compliance before and after walls are closed. If you're planning a renovation and want to understand your electrical upgrade options, Toronto Electrical Repair can connect you with licensed electricians who can assess your existing wiring and recommend the most cost-effective approach for your situation.