Most homes built before 1980 have 100-amp service — inadequate for modern EVs, HVAC, and appliance loads. Upgrading to 200-amp costs $1,500–$3,500. Upgrading to 400-amp (needed for solar, two EVs, or whole-home electrification) costs $3,500–$8,000. The utility company may need to upgrade the service entrance separately, which can add $500–$2,000 and 2–8 weeks of wait time.

Homes with knob-and-tube wiring (pre-1940s) or aluminum branch circuit wiring (1965–1973) require full rewiring for safety and insurability. Many insurers now refuse coverage or charge significant premiums for these systems. Full rewiring costs $8–$15/sf depending on home size and accessibility. Partial rewiring of specific circuits is cheaper but may not satisfy insurance requirements.

Rewiring an open-framed home under construction costs 40–60% less than rewiring a finished home where walls must be opened and patched. Homes with accessible attics and crawlspaces cost less to rewire than slab-on-grade homes where wiring runs through finished walls. Drywall repair after rewiring adds $500–$3,000 to the total cost.

All electrical panel work and rewiring requires permits in every US jurisdiction. Permit fees run $150–$500 depending on project scope and municipality. Work must be inspected by a licensed electrical inspector before walls are closed. Unpermitted electrical work is a serious liability at resale and voids homeowner’s insurance coverage for any related claims.