Do I need to rewire my house?

Probably not. Most people who ask this need a consumer unit and one or two circuits renewed — a job in the low four figures rather than the high ones. There are five findings that genuinely justify a full rewire, and "the house is old" is not among them.

Age is not a fault

The most expensive misconception in domestic electrics is that wiring has an expiry date. It does not. PVC-insulated cable installed in the 1970s, kept dry and not overloaded, can still pass insulation-resistance testing today. Meanwhile a badly executed alteration from 2015 can fail. What matters is condition and arrangement, both of which are measurable — so the question is answerable with a test rather than a guess about the decade.

That is worth holding on to when someone quotes you for a rewire on the strength of a look round. Nobody can tell you the state of the insulation inside a wall by looking at the sockets.

The five findings that genuinely justify a full rewire

1. Rubber-sheathed or lead-sheathed cable. Rubber insulation perishes — it goes hard, then cracks, and it does so everywhere at once because it is all the same age. Lead-sheathed wiring is older still. If either is present in more than an isolated leftover run, the answer is a rewire, and it is not a close call.
2. No earth at the lighting circuits. Common in pre-1960s installations and in some 1960s ones. At minimum every lighting circuit needs replacing, and because lighting cable runs through the least accessible parts of the house, that is most of the disruption of a full rewire anyway. Usually cheaper to do the lot.
3. Widespread C2 observations across most circuits. Not two or three items — most of them. At that point pricing each observation separately costs more than replacing the installation, and you still own an old installation at the end of it.
4. Insulation resistance failing on multiple circuits. This is the measured version of the point above, and it is the single most objective signal available. Ask for the readings.
5. You are doing the building work anyway. Full refurbishment, floors up, walls coming off, extension going on. The marginal cost of rewiring while the fabric is open is a fraction of doing it later, and this is the one case where rewiring sound wiring is still rational.

What does not justify one

The fourth row catches people out in Harlow in particular. The town's post-war new-town stock has largely been part-rewired at least once, so a single surviving legacy circuit sitting alongside three sound modern ones is a normal finding here — and it is a partial job, not a whole-house one.

How to find out for about £119

An EICR tests every circuit and reports it individually, with readings. For a three-bedroom house that is roughly £119. It replaces the entire argument above with a document, and it tells you which of these you are actually dealing with:

If the answer is yes

Then two things are worth knowing before you get quotes, because both cost more than people expect. First, the electrician's price is not the job's price: replastering commonly adds £800–£2,500 and is usually not in the quote at all. Second, the electrical work on a three-bed is 5–7 days but the house is disrupted for three to four weeks once plaster drying and decorating are counted.

Both are broken down on what a rewire really costs, along with the all-in figure rather than the electrical-only one. If you intend to stay in the property while it happens, read how long a rewire actually takes and ask for the work to be staged floor by floor before the quote is written.

One thing to check regardless

Whatever the scope turns out to be, it will be notifiable — new circuits always are. Confirm whoever you hire is on the Registered Competent Person Electrical register so they can self-certify and notify Building Control. On a rewire that certificate is the asset you are really buying: it is what answers the question cleanly when you sell.