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Cost to Rewire a House in Ontario (2026): When to Do It, With and Without the Panel, Plaster Patching, Living in It, and Insulating While the Walls Are Open
Electrical & Lighting
Rewiring an Older House: The Wire Is the Cheap Part, the Walls Are Not
A rewire is one of those jobs where the number on the quote and the number you end up paying are often far apart, and almost all of the gap is in the plaster. This page covers when a house really needs rewiring and when a smaller fix will do, what it costs with and without the panel, the patching nobody puts in the first number, what it is like to live in the house while it happens, and the insulation work worth doing while the walls are open.
The numbers
$5 to $15per sq ft, depending on access
$8,000 to $22,5001,500 to 2,000 sq ft rewire
$2,000 to $8,000drywall and plaster patching, extra
$40 to $100per point to pigtail aluminum instead
| Job | Range | Default or note |
|---|---|---|
| Whole-house rewire, per sq ft | $5 to $15 | $10 |
| Whole-house rewire, 1,500 to 2,000 sq ft | $8,000 to $22,500 | patching extra |
| Drywall and plaster patching | $2,000 to $8,000 | plus paint |
| Knob-and-tube replacement, 1,500 to 2,500 sq ft, with panel | $12,000 to $25,000 | large older houses to $45,000 |
| Plaster patching after knob-and-tube | $2,500 to $8,000 | plus paint |
| Panel replacement, same amperage | $1,500 to $3,000 | $2,200 |
| 100 A to 200 A upgrade, overhead | $2,500 to $5,000 | $3,800 |
| 100 A to 200 A upgrade, underground with a trench | $5,000 to $7,000 and up | |
| Aluminum pigtailing, typical house of 40 to 60 points | $2,000 to $6,000 | assessment $100 to $250 |
| Electrical safety inspection with written report | $250 to $450 | for insurance or a purchase |
| ESA fee, service change or panel upgrade | $92 | contractor minimum; $212 homeowner |
October 2026, before HST. Most published rewire prices do not say whether the panel is in. This page carries the panel or service as its own line so it is not missed; if a quote already includes it, take it out of that line rather than paying for it twice.
Why Ontario prices are all over the map: the contractors and price guides we checked for this page quoted very different prices for a rewire. A national home-services marketplace said $8,000 to $20,000. A GTA electrical contractor said $15,000 to $30,000 for 1,200 to 2,500 sq ft. Patching was often not in either. The gap is access: an open basement ceiling and a hollow attic are fast, plaster on lath over three storeys is slow, and whether the panel, the service and the patching are in the price moves it again. Budget $10 a square foot plus a patching allowance, and get two or three quotes on the same written scope.
When a House Needs Rewiring, and When It Does Not
Old does not mean dangerous, and new paint does not mean safe. On any older house, the honest question is what the wire is, what condition it is in, and what has been hung off it since 1955.
- Knob-and-tube. ESA allows it to stay if it is on 15 A protection, the conductors are sound and nobody has added outlets to overload the circuit. Where it shows abuse or deterioration it gets replaced, and many insurers will not insure or renew without an inspection or replacement.
- Aluminum branch wiring, in houses from the mid-1960s to the late 1970s. It does not have to be ripped out. Pigtailing every termination with copper and AL-CU rated connectors is a repair ESA accepts, at $40 to $100 a point. Insurers may still ask for an inspection and an ESA Certificate of Acceptance.
- Ungrounded two-wire circuits, a fuse box, a panel full of doubled-up breakers, or a house that has been “improved” by three owners with extension cords in the walls. That is where a rewire usually earns its price.
- A renovation that opens most of the walls anyway. If the plaster is coming off, the wire behind it is the cheapest part of the job.
The way to find out is an electrical safety inspection by a licensed electrician, $250 to $450 with a written report. What each old wiring type looks like and what ESA allows is on the aluminum and knob-and-tube page. If a receptacle is hot or discoloured, or you smell burning, do not wait for the inspection: turn the breaker off and call a licensed electrical contractor today.
Three Houses, Added Up
| House | Line | Basis | Cost |
|---|---|---|---|
| A. 1,600 sq ft 1950s bungalow, drywall, open basement | Rewire | 1,600 x $10 | $16,000 |
| Panel replacement, stays at 100 A | default | $2,200 | |
| Drywall patching | allowance | $4,000 | |
| Total | $22,200 | ||
| B. 2,000 sq ft 1920s two-storey, plaster, knob-and-tube | Rewire, harder access | 2,000 x $11 | $22,000 |
| 100 A to 200 A, overhead | default | $3,800 | |
| Plaster patching | allowance | $6,000 | |
| Total (paint extra) | $31,800 | ||
| C. 1,800 sq ft 1972 split-level, aluminum | Assessment | middle of $100 to $250 | $175 |
| Pigtail 50 points with AL-CU connectors | 50 x $70 | $3,500 | |
| Total, pigtailing | $3,675 | ||
| Or: full copper rewire plus patching | 1,800 x $10 + $3,000 | $21,000 |
Before HST. In House B the utility disconnect and reconnect for the service change is extra unless your utility does it free: Hydro One does one a calendar year for an upgrade at no charge with 10 days notice, Toronto Hydro charges $120 at the meter in regular hours, Alectra $65 at the meter in its PowerStream rate zone. Ask your own utility before you accept a contractor’s line for it.
House C is the one people overspend on. Pigtailing done properly by a licensed contractor costs about a sixth of a rewire, $3,675 against $21,000, and fixes the part of aluminum wiring that causes trouble, the connections. If the walls are coming open for a renovation anyway, the arithmetic changes. The panel and service side, the 100 A versus 200 A decision and the utility steps, are on the panel upgrade cost page.
Living in the House While It Happens
Many rewires are done with the family still in the house, and it can be done, but it is a renovation, not a service call. The electrician works a section at a time, so some rooms are without power for part of each day. Plan for that, and ask for it in writing.
- Ask for the sequence. Which rooms are off on which days, and which circuit keeps the fridge, the furnace and the sump pump going.
- Move the furniture out of the way, and the valuables out of the house. There will be holes in walls and dust in rooms you did not think were involved.
- Agree who patches. The electrician cuts the access holes. Unless the contract says so, they do not fill them, and they certainly do not paint.
- Nothing gets closed until ESA authorizes it. The inspector sees the new wire before the patching covers it. A patcher who arrives early is a patcher who comes back.
- Get the Certificate of Acceptance. Only ESA issues it, to whoever filed the notification, when the work passes. Your insurer will ask for it.
The work must be done by an ESA Licensed Electrical Contractor with a 7-digit licence number you can check on ESA’s contractor locator on esasafe.com. A general contractor is not licensed to do it. A homeowner may rewire their own home, but files the notification themselves before starting and passes the inspection; the ESA permit page covers the fees and steps. On our own renovations in Simcoe, Muskoka and Georgian Bay, the electrical is done by the licensed contractors I hire, under their licence and their notification.
Insulate and Air Seal While the Walls Are Open
A rewire is the one time in fifty years that every ceiling and wall cavity in an old house has a hole in it. That is the time to fix the air leaks and the insulation, because you have already paid for the holes.
Knob-and-tube and insulation do not mix: the old wire was designed to shed its heat into open air, so burying live knob-and-tube in insulation is not a weekend job with a rented blower. Once it is out and the new cable is in, the attic can be air sealed and insulated properly. The knob-and-tube and insulation page and the insulating older homes page go through the order. Seal the new box penetrations in the top-floor ceiling as you go; every one is a little chimney into the attic.
Questions people ask
How much does it cost to rewire a house in Ontario?
About $8,000 to $22,500 for 1,500 to 2,000 sq ft, or $5 to $15 a square foot depending on access, before HST. Drywall and plaster patching adds $2,000 to $8,000, and a new panel or service upgrade is another $1,500 to $5,000 if it is not already in the price.
How much does knob-and-tube replacement cost?
$12,000 to $25,000 for 1,500 to 2,500 sq ft including the panel, up to $45,000 in large older houses, plus $2,500 to $8,000 of plaster patching and the paint.
Do I have to replace aluminum wiring?
Not necessarily. Pigtailing every termination with AL-CU rated connectors, $40 to $100 a point and $2,000 to $6,000 for a typical house, is accepted by ESA when done properly. Some insurers want an inspection and a Certificate of Acceptance afterward.
Can I live in my house while it is rewired?
Usually, yes. The electrician works in sections, so rooms lose power for parts of the day. Ask for the sequence in writing and keep the fridge, furnace and sump on a working circuit.
Do I need a permit to rewire my house?
Yes, an ESA notification filed before the work starts, by the licensed contractor or by you if you are doing your own home. Nothing gets covered until ESA authorizes it.
Price your rewire
The whole-house electrical cost calculator handles a rewire as well as a new house: square feet, access, the panel and a patching allowance, with nothing counted twice. If you already have rewire quotes, the $99 review reads up to three of them and tells you which left out the panel, the patching or the permit.
Sources and further reading
- ESA: knob and tube wiring: when it may stay, when it should go, and what insurers often ask for.
- ESA: aluminum wiring: what to look for in a 1960s and 1970s house, the approved repair methods and the insurance question.
- ESA 2026 Fee Guide: the actual ESA fees for a new house, a service change, an EV charger and renovation work, contractor and homeowner rates.
