House rewiring cost

Rewiring a house costs $6 to $17 per square foot, so $9,000 to $25,500 for a 1,500 square foot house. Replacing knob and tube wiring costs more, $10 to $20 per square foot, because the old wiring has to come out rather than simply be abandoned.

Those figures usually exclude the wall repair. That is the number people miss, and on a plastered house it can be a third of the project.

Cost by house size

Aluminum branch circuit replacement adds 15% to 25% over a standard rewire.

The spread within each row is mostly access. A single-story house with a full basement and a walkable attic is the easy case: an electrician can reach most walls from above and below without opening them. A two-story house on a slab with plaster walls is the hard case, and it is the difference between the low and high columns.

The wall repair is a separate trade

Rewiring means getting cable inside finished walls, and that means holes. A careful electrician cuts small, regular openings and keeps them where they can be patched. There will still be dozens.

• Drywall patch: $300 to $1,500 per opening, depending on size
• Ceiling repair: $50 to $100 per square foot in drywall
• Lath and plaster repair: $50 to $125 per square foot, and matching an old plaster texture is genuinely difficult
• Painting afterwards, which is a whole-room job because patches never match

Ask every quote whether patching is included, and whether that includes texture and paint. Two quotes $8,000 apart are frequently just this.

When a house needs rewiring

Knob and tube. Cloth-insulated wire on ceramic knobs, used until about 1950. It is not automatically dangerous, but the insulation embrittles, it has no ground conductor, and it fails badly when buried in modern insulation. Many insurers will not write a policy on a house with active knob and tube, which frequently forces the decision.

Aluminum branch wiring. Used from roughly 1965 to 1973 during a copper price spike. Aluminum expands and contracts more than copper, and connections at outlets and switches loosen over time and overheat. The Consumer Product Safety Commission has flagged it as a fire risk.

Full replacement is one answer. The cheaper one is COPALUM crimping or approved AlumiConn connectors at every device, which pigtails copper onto the aluminum. That runs $50 to $150 per connection, so $2,000 to $6,000 for a house, against $12,000 or more for a rewire. Ask about it: many electricians quote the rewire without mentioning the alternative.

No ground. Two-prong outlets throughout means an ungrounded system. Modern electronics and anything with a metal case want a ground. A whole rewire is one fix; GFCI protection on ungrounded circuits is a code-permitted alternative that costs a fraction, though it does not give you a true ground.

Cloth-sheathed cable that is crumbling, visible at the panel or in the basement.

Symptoms. Breakers that trip repeatedly, lights that dim when an appliance starts, warm switch plates, a burning smell, outlets that no longer grip a plug.

Doing it in phases

A whole-house rewire in one go is disruptive enough that many people cannot live through it. Phasing works and costs 20% to 40% more in total.

The sensible order:

1. The panel and the service, because everything else feeds from it
2. Kitchen and bathrooms, which have the most demanding code requirements and carry the most risk
3. Bedrooms, where arc-fault protection matters most
4. The rest

Doing it room by room during other renovations is the cheapest version of all: the walls are already open and the electrician is not paying for access.

What a good quote covers

• The number of circuits and what each serves
• New devices throughout, or whether existing ones are reused
• AFCI and GFCI protection where code requires it
• Whether the panel is included
• Smoke and carbon monoxide detectors, which most jurisdictions require to be interconnected and hardwired when a house is rewired
• Wall repair, and to what standard
• Permit and inspection
• Whether you can live in the house, and for how long the power is off

That detector line catches people out. Interconnected hardwired detectors in every bedroom and on every level are commonly triggered by a rewire permit, and they add $500 to $1,500.

Frequently asked questions

How long does it take?

One to two weeks for a small house, three to six for a large or difficult one, plus the patching and painting afterwards. Power is off in the area being worked on, not the whole house, for most of it.

Can I live in the house?

Usually, with disruption. Furniture gets moved to the middle of rooms, there is dust everywhere, and power comes and goes. Many people move out for the kitchen and bathroom phase.

Does rewiring add value?

Not visibly, and that is the frustrating part: you spend $18,000 and the house looks identical. It removes a reason for buyers to discount or walk away, and on a house with knob and tube or aluminum it can be the difference between selling and not.

Is knob and tube illegal?

Not generally. Existing installations are usually permitted to remain, but it cannot be extended, and covering it with insulation violates most codes. The practical pressure comes from insurers rather than inspectors.

Can I just replace the outlets?

Replacing a two-prong outlet with a three-prong one without a ground conductor is a code violation and it is dangerous, because it tells every appliance there is a ground when there is not. The permitted alternative is a GFCI outlet labeled "no equipment ground". That is a legal and much cheaper fix, and it is not the same as having a ground.