What it is, and where it turns up
Knob-and-tube is the original wiring in a lot of houses from the 1900s and 1920s. Two separate conductors, run apart from each other, held off the framing by ceramic knobs and threaded through ceramic tubes where they pass through joists. No ground wire. The outlets it feeds have two slots, not three.
You find it in basements, in attics, inside closet ceilings, and in the boxes above a plaster ceiling that nobody has opened since the Truman administration. It usually travels with a fuse box or a small early panel.
Plenty of Delco houses have already been half rewired. A previous owner did the kitchen and the second floor and left a few original circuits running the hall light. That’s the common case, and it’s also the one that gets argued about.
What the appraiser does about it
Less than people expect. HUD Handbook 4000.1 has no knob-and-tube rule at all, and anyone who tells you FHA bans it is repeating a rumor.
What the handbook has is a standard. The electrical system is a deficiency if it “is not adequate to support the typical functions performed in the dwelling without disruption.” So the appraiser looks for visible frayed or exposed wire, basement and garage included. Amperage and panel size get reported if they look short. A sample of switches, fixtures and receptacles gets operated. The appraiser is not required to open the panel.
A working old system can clear that bar. A lender can still layer its own overlay on top, so the answer on any specific house is subject to lender approval. The appraisal guide walks the rest of the list.
What the insurer does, and why it’s the real gate
Here’s the part that catches people. Insurers are not bound by HUD’s handbook. Each carrier writes its own underwriting rules on old wiring, and they range from no comment, to a surcharge, to a flat decline until the house is rewired.
Your lender cannot close without evidence of hazard insurance in the file. That’s a required document in the FHA case binder and it’s standard on every other loan type too. So the sequence that kills deals looks like this: appraisal comes back fine, underwriting clears, and then no carrier will bind on a house with active knob-and-tube five days before settlement.
Nobody did anything wrong, and it still costs you the settlement date. One phone call in week one avoids it.
The sequence that keeps this from blowing up
- Write the offer with a real inspection contingency. Give yourself room in the timeline.
- Get the home inspection. Ask the inspector specifically what’s original, what’s live, and what the panel is.
- Call an insurance agent the same week, with the inspector’s language in hand, and ask for a quote on the house as it stands. Get the answer in writing.
- Let the appraisal happen. Now you know whether an appraisal condition and an insurance decline are pointing at the same circuits.
- Decide: seller repairs before closing, a price adjustment, a rewire you finance, or you walk.
Do that in that order and the surprise happens in week one, when it’s still a negotiation. Do it backwards and it happens at the table, when it’s a cancellation.
What rewiring actually involves
New service and a new panel, then home runs fished through walls, ceilings and closets, then plaster patching, then permits and a municipal electrical inspection. In a twin with a finished basement and lath-and-plaster walls, the patching is a real part of the job.
Get two written quotes, itemized, with the panel and the permit broken out. We don’t publish price ranges for this work, because there’s no source worth quoting on a house we haven’t seen; an electrician standing in your basement is the source.
Worth knowing before you buy: several Delco boroughs want an electrical sign-off at resale regardless of your loan. Prospect Park asks for third-party electrical certification. Aldan and Ridley Park list electrical and chimney certificates. Eddystone lists electrical and heating. Upland checks the service cable. That’s the U&O layer, and it runs on its own rulebook.
Where a 203(k) fits
If the seller has no money and no interest, the rewire can go into the mortgage.
FHA 203(k) Limited covers total rehabilitation costs up to $75,000, raised from $35,000 for case numbers assigned on or after November 4, 2024. Minor remodeling and nonstructural repairs only, which a rewire generally is. Nine months to complete under the borrower and contractor agreement. A consultant is optional and the consultant fee is now financeable. Energy improvements can sit on top of the $75,000.
Standard 203(k) is for the bigger jobs: minimum $5,000 of eligible improvements, a consultant from the FHA roster, structural work allowed, twelve months to finish, and up to twelve months of mortgage payments financeable if you can’t live there while the work runs.
Either way it’s one loan, closed on the value after the work, and the contractor gets paid from draws instead of from you. Which version fits is the lender’s call.
Who pays for it
Three normal outcomes on a Delco twin. The seller rewires before closing, usually only if the house has been sitting. The price comes down and you handle it after settlement, which insurance may or may not allow. Or the work goes into a 203(k) and the loan carries it.
An escrow holdback is sometimes floated as a fourth option. Whether that’s available is entirely up to the lender, so ask before you write it into a contract.