Yes, you can sell. Selling a house with knob and tube wiring in Massachusetts is legal, and no state rule forces you to rewire before a sale. What the wiring changes is who can buy. A buyer’s home inspector will almost always flag it, the buyer’s insurance company will usually ask about it, and if the system is in poor shape a lender may not finance the purchase until it is dealt with. So the practical question is not whether you are allowed to sell, but whether you rewire first, give the buyer a credit, or sell the house as it is to someone who does not need a mortgage.
The rest of this article covers what knob and tube is, why buyers and insurers react to it, what rewiring involves in Massachusetts, and how to choose between those three routes. It is general information, not electrical or legal advice. A licensed Massachusetts electrician should look at the actual system before you set a price or promise anything.
What knob and tube wiring is, and how to tell if you have it
Knob and tube is the earliest form of household wiring. Single conductors run separately through ceramic knobs and tubes in the framing, with no ground wire. The City of Boston’s guidance on barriers to installing insulation notes that it was a common way to wire homes up until the 1940s, that it has no ground wire, and that its protective casing deteriorates over time and can become a fire hazard.
That date range matters in Massachusetts, where a large share of the housing stock, especially in the older cities and inner suburbs, went up before the war. Plenty of those houses were partly rewired decades ago, so knob and tube often survives in pockets rather than throughout: a few ceiling circuits, the third floor of a triple-decker, the walls nobody opened during a kitchen remodel. You can sometimes spot the white ceramic knobs in an unfinished basement or attic. Two-prong outlets and an old fuse box are hints but not proof, and the reverse is true too, because a modern panel can still be feeding old wire. Only an electrician tracing the circuits can tell you how much is left and whether any of it is live. A house from a slightly later era, roughly the 1960s and 1970s, is more likely to have aluminum branch circuit wiring instead of knob and tube, which is a different repair problem with its own fix.
Why buyers, lenders and insurers care
Three different parties look at the same wiring for three different reasons.
The buyer’s inspector reports it because it is ungrounded, often more than 80 years old, and frequently modified by later owners. The inspector’s report does not stop a sale, but it gives the buyer a clear, documented reason to ask for a credit, ask for repairs, or walk away during the inspection period.
The insurer asks because older wiring is an underwriting question. Some companies ask for an electrician’s letter, some want the active knob and tube removed, and some will not write the policy at all. That varies by company and changes over time, so the only reliable answer comes from the buyer’s own agent. Buyers who are turned down in the regular market can apply to the Massachusetts Property Insurance Underwriting Association, the state’s FAIR Plan, which chapter 175C of the General Laws sets up to offer basic property insurance to eligible applicants. Coverage there is narrower than a standard homeowners policy, so it is a fallback rather than a fix.
The lender’s concern is narrower still. An appraiser is judging whether the house is safe and habitable, not whether it is modern. Old wiring that works and shows no obvious hazard often passes. Wiring that is visibly damaged, spliced into, overloaded or partly dead is a different matter, and it can hold up a loan until it is repaired.
| Who looks at it | What they are deciding | What usually happens |
|---|---|---|
| Home inspector | Whether to flag a defect for the buyer | Almost always noted, often with a recommendation for an electrician |
| Insurer | Whether and on what terms to cover the house | Varies by company, from no issue to a required letter or removal |
| Lender and appraiser | Whether the house is safe enough to lend against | Working, undamaged wiring often passes; hazards can stall the loan |
Does knob and tube wiring stop a mortgage?
Not by itself, in our experience. The line lenders draw is safety, not age. Across the deals we see, the things that reliably kill a buyer’s mortgage are serious structural problems, major fire or water damage, and electrical or plumbing that is substantially unsafe or not working. A house that is simply old and ugly usually still gets a conventional loan. So a knob and tube house where the old circuits are intact and working is usually financeable, while one with scorched insulation, amateur splices or dead circuits may not be. If you want to see how the same safety test plays out for structural defects, our guide to selling a house with foundation problems in Massachusetts walks through it.
What rewiring involves in Massachusetts
If you decide to fix it first, the work is regulated. Under chapter 143, section 3L, anyone installing electrical wiring for hire must give notice to the local inspector of wires, using the state permit application form, before the work starts or within five days of starting it, must notify the inspector in writing when it is finished, and the inspector then has five days to approve or disapprove the work. In practice that means a licensed electrician, a permit pulled with your town, and an inspection before the walls close.
Three things tend to surprise sellers about the job.
- It is rarely just wire. Pulling new cable through finished plaster walls means opening walls and ceilings, then patching and painting them. That repair work can rival the electrical bill.
- It often triggers other upgrades. Old service equipment, a full fuse panel and missing smoke and carbon monoxide detection tend to be addressed at the same time.
- The paperwork is part of the value. A closed permit and a signed-off inspection are what a buyer’s attorney and inspector will want to see. Rewiring without them can create an open or unpermitted work problem, which we cover in our piece on selling a house with unpermitted work.
There is also an energy efficiency angle. Boston’s guidance says insulation can still go in as long as the knob and tube system is inactive, and that the Mass Save HEAT Loan offers 0 percent financing toward knob and tube mitigation. That program is aimed at owners who are staying and weatherizing, but it is worth knowing about if you are deciding whether to fix the wiring or sell.
We cannot give you a reliable rewiring price, because it depends on the size of the house, how many circuits are still original, and how much plaster has to come down. Get at least two written quotes from licensed electricians before deciding.
Selling a house with knob and tube wiring: rewire, credit, or sell as-is
Once you know how much knob and tube is left and whether it is live, the choice usually comes down to three routes.
Rewiring before listing makes sense when the house is otherwise in good shape and aimed at buyers using a mortgage, since it removes the inspection objection and the insurance question in one go. The cost is time, cash up front and living with open walls, and you rarely recover every dollar in the price.
Offering a credit makes sense when the rest of the house is sound and you would rather not manage a renovation. You list with the wiring disclosed, attach an electrician’s assessment and quote, and let the buyer do the work after closing. The risk is the buyer’s insurer or lender, which can still slow or sink the deal after you have accepted an offer.
Selling as-is to a cash buyer makes sense when the wiring is one of several problems or you need a firm date. No lender or appraiser is involved. In our experience, a seller who describes a house as needing “some updating” often turns out to have 40-year-old electrical along with a tired roof or water in the basement, and our number typically moves 5 to 15 percent between the phone call and the walkthrough, usually downward, for exactly that reason. Old wiring behind plaster is one of the items we budget conservatively, because the cost is in what the walls hide. As a rough guide, our offers usually run 60 to 70 percent of the after-repair value, closer to 55 to 60 percent on a heavy rehab, and a clean deal typically closes in two to four weeks once title is checked.
What sellers usually ask about old wiring
Do I have to disclose knob and tube wiring?
What you must say depends on the facts and on what you are asked, so this is a question for your attorney. As a practical matter, a seller who knows about a defect should not hide or misstate it, and a buyer’s inspector will usually find it anyway. Answer questions truthfully and ask a real estate attorney how to word any written disclosure.
Is it enough to disconnect the old circuits?
Sometimes. Old wire left in the walls but fully disconnected is generally treated very differently from live wire, and Boston’s insulation guidance turns on whether the system is inactive. A licensed electrician should confirm and document that it is dead.
Will a buyer’s insurer refuse the house?
Some will and some will not. Ask the buyer’s agent to get an insurance quote early in the inspection period rather than after the loan is approved.
Does a partly rewired house still count as knob and tube?
If any original circuit is still live, most inspectors and insurers will treat it as having knob and tube. Knowing exactly which circuits remain is what lets you give a buyer a straight answer.
If the wiring is one of several things you would rather not take on, you can get a cash offer on the house as it stands and weigh it against an electrician’s quote before deciding.
Homeowners We’ve Helped
Boston Investors
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After 94 days on the market, two buyers backed out over the roof and septic. We were tired of dealing with it. The cash offer came without asking us to make the repairs, and we closed in 21 days. Once we looked at the actual numbers, it made much more sense than continuing to list. The whole process was simple and we’re very happy with how it worked out.
