Redoing the Complete Electrical Installation in a House

Rewiring an entire house is the sort of renovation that often raises plenty of questions about cost, timescales and safety. Unlike repainting or replacing flooring, the wiring is hidden away, which can make it harder to see where the money is going-even though the work follows well-defined technical criteria and can be planned with a reasonable degree of predictability.

How much does it cost to redo a house’s electrical installation?

The price of a full electrical refit changes depending on the floor area, how many rooms there are, the number of light points and sockets, and the quality level of the materials chosen. In many Brazilian cities, it is common to combine a price per square metre with a count of electrical points, adjusting the overall figure to match what the design requires.

Lighting typically accounts for a smaller share of the budget, while sockets intended for high-demand appliances-such as air conditioning, electric showers and heaters-push the final cost up. Older properties usually need more corrective work too, including replacing consumer units and opening up walls, which increases both the duration of the job and labour costs.

Watch a video on the YouTube channel World of Electrical about planning a residential electrical renovation, material costs, and why hiring qualified professionals matters:

https://www.youtube.com/watch?v=y3n9E94oI1M

Which factors most affect the price of an electrical renovation?

When you choose to redo the electrical installation, certain elements have an immediate effect on the budget-especially if the goal is to prepare the home for modern equipment and possible future extensions. Beyond the quantity of materials, the total also needs to allow for planning, testing, and any structural adjustments required in the property.

Among the items that most often change the overall cost, it is worth paying close attention to:

• Size of the house: a larger area means more cables, conduits and fittings.
• Number of circuits: adding more circuits improves safety, but requires more circuit breakers and more time on site.
• Material specification: well-known brands and devices such as RCD (DR) and surge protection (DPS) increase the spend, but provide greater protection.
• Condition of the old installation: very outdated systems typically demand more masonry repairs and compliance updates.
• Ease of access: concrete slabs and old pipework can make the work slower and more complex.

Why is it important to hire a qualified professional for electrical installation work?

Electrical renovations involve load calculations, correct cable sizing, selecting circuit breakers, and choosing protective devices against electric shock and voltage surges. A mistake can lead to overheating, frequent power trips and serious safety risks, which is why it is essential to follow technical standards such as NBR 5410, as well as the requirements set by the local utility.

With a properly qualified professional, the homeowner gets circuits sized appropriately, a layout of light points and sockets that matches how each space is actually used, and provision for dedicated circuits for electric showers and air conditioning. Circuit diagrams or recorded schedules also make future maintenance simpler and help faults be identified quickly.

What signs show it’s time to redo the electrical installation?

Before signing off on a complete overhaul, it is sensible to confirm whether replacing the wiring is genuinely necessary. Some warning signs indicate the electrical system can no longer keep up with today’s demand or may be putting residents at risk.

Circuit breakers that trip regularly, warm sockets, a burning smell, systems that have gone decades without an upgrade, and heavy reliance on extension leads are all red flags that need immediate attention. In many situations, fully replacing the wiring is more effective than isolated repairs, and it can be planned alongside other renovations-such as new wall finishes and painting-to reduce disruption, repeated break-outs and rework.