Most owners of older homes don't know whether knob-and-tube or aluminum wiring is still in use, especially after partial updates.
Electrical play · Rewiring
Rewiring leads from homes built in the knob-and-tube and aluminum wiring eras.
Older wiring hides in walls and attics, and most homeowners only learn about it when an insurer asks or an inspection flags it. Spur finds homes built in the eras when knob-and-tube and aluminum branch wiring were common, writes a plain-language letter about what that means, and offers a free wiring inspection.
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USPSFirst-Class
Catherine Doyle5307 Roland AveBaltimore, MD 21210Scan for a free wiring inspection
Catherine D. requested a wiring inspection · 29 min ago
AI-written for this owner · Mailed in 2 days
Pre-1950homes most likely to have knob-and-tube wiring
1965–1973era of aluminum branch-circuit wiring
55×more likely to reach fire hazard conditions: older aluminum vs. copper connections
The problem
Old wiring is invisible until an insurer or inspector finds it.
Some insurers ask about knob-and-tube or aluminum wiring before writing a policy, and inspection reports flag it during a sale.
A whole-house rewire is a large, disruptive job. A coupon won't sell it. A clear explanation of the risks and the process will.
How it works
From list to mailbox in one workflow.
Five steps from a wiring-era list to a rewire estimate.
app.usespur.com
See it in Spur
A rewiring list in Spur
Sample older homes in north Baltimore likely to have some original wiring. Names are partly masked.
Zip 21210Single-familyOwner-occupiedBuilt before 1950Owned 10+ yrs
- Catherine D.5307 Roland Ave2,860 sq ft · built 1924Knob-and-tube eraOwned 19 yrs
- Ben & Ivy S.614 W Lake Ave3,240 sq ft · built 1917Knob-and-tube eraOwned 23 yrs
- Charles O.5512 Purlington Way2,110 sq ft · built 1938Owned 12 yrs
- Nadia F.702 Edgevale Rd2,540 sq ft · built 1929Knob-and-tube eraOwned 31 yrs
- Peter G.5110 Falls Rd Ter1,890 sq ft · built 1946Owned 15 yrs
AI draft for Catherine D. · 5307 Roland Ave
Dear Catherine,
Your home on Roland Avenue was built in 1924. Many homes of that era in Roland Park still have some original knob-and-tube wiring, often alongside newer circuits added over the years.
Knob-and-tube wasn't designed for today's electrical loads, has no ground wire, and its insulation becomes brittle with age, especially where it's been covered by attic insulation. Some insurers ask about it, and it often comes up when a home is sold.
We'll inspect your wiring for free and tell you honestly what you have. If updates make sense, we'll explain how we rewire older homes with minimal wall damage and in stages if you prefer. Scan the code to book.
Dan Mercer · Chesapeake Electric · MD Master Electrician #12408 · (410) 555-0167
Sample data for illustration. Your results depend on your market and filters.
Playbook
How to find and sell rewiring work in older homes
Rewiring jobs are large, but the homes that need them are predictable from build year. Two eras matter most. Knob-and-tube wiring, with single conductors run through ceramic knobs and tubes, was standard in homes built from the late 1800s into the 1940s. Aluminum branch-circuit wiring was used in many homes built or expanded from about 1965 to 1973, when copper prices spiked.
Both carry real issues. Knob-and-tube has no ground conductor, wasn't designed for modern loads, and its insulation can deteriorate, especially where it has been buried under attic insulation. The U.S. Consumer Product Safety Commission reports that homes wired with older aluminum wire manufactured before 1972 are 55 times more likely to have one or more connections reach fire hazard conditions than homes wired with copper. Remediation options for aluminum, such as approved connectors or pigtailing, can be less disruptive than a full rewire.
Homeowners often learn about their wiring from someone else. Some insurers ask about knob-and-tube or aluminum wiring when writing a policy, and home inspectors flag both during a sale. That gives you a factual, non-alarming reason to reach out: "homes of your era often have this; here's how to find out."
Sell with an inspection and a letter. A whole-house rewire is a significant expense and a disruptive project, so a sealed letter that explains the home's era, the likely wiring, and how you minimize wall damage is more persuasive than a postcard. Offer to rewire in stages, starting with the highest-risk circuits, which makes the decision easier.
Plan a longer cycle. Three touches over two to three months, same-day callbacks on scans, and a place on your list for homeowners planning a remodel, which is the most natural time to rewire.
Tie the message to what the homeowner already cares about. Owners of older homes are often planning a remodel, adding insulation, or dealing with an insurer's questions. Each of those is a natural moment to rewire, and a letter that names it makes the decision easier.
24×return on a year of Spur Team from one $14,000 rewire
One rewire pays for years of mail.
- Spur Team: $588/yr, plus 400 older homes × 3 letters = 1,200 letters at $1.29 = $1,548
- One $14,000 whole-house rewire = 24× your subscription
- Add two $2,500 aluminum remediation jobs, and the year returns 9× the software and postage combined
Example math. Rewire pricing depends on home size, access, and how much original wiring remains. Run your own numbers →
One tool, not four
Spur vs. the usual way to find rewiring jobs
What you needThe usual waySpur
Homes built in the K&T and aluminum erasInspection referrals only✓ Built in
Owner contact detailsSeparate data vendor✓ Built in
Letter that explains their wiringGeneric electrical coupon✓ Built in
Sealed letter printing and mailOffice printer and stamps✓ Built in
Multi-month follow-upCalendar reminders✓ Built in
Rewiring Leads by the numbers
Why older wiring deserves a look
55×
homes with pre-1972 aluminum wire are more likely to have connections reach fire hazard conditions than copper-wired homes
46,700
U.S. home fires a year involved electrical failure or malfunction (2015–2019 average)
24×
return on a year of Spur Team from one $14,000 rewire
FAQ
Rewiring lead questions
How do electricians find homes that need rewiring?
Target build years. Homes built before about 1950 often have some knob-and-tube wiring, and homes built or expanded from 1965 to 1973 may have aluminum branch wiring. Filter to owner-occupied homes held 10+ years.
Is knob-and-tube wiring dangerous?
It isn't automatically unsafe, but it has no ground, wasn't designed for modern loads, and its insulation can deteriorate, especially under attic insulation. An inspection tells you its condition.
Does aluminum wiring need to be replaced?
Not always. Approved remediation methods such as special connectors or pigtailing can address the connection risk without a full rewire. An inspection shows which option fits.
Should rewiring offers be letters or postcards?
Letters for the first touch. A rewire is a significant decision, and a sealed letter can explain the home's era, the wiring, and the process.
How long do rewiring leads take to close?
Often a few months. Plan three touches over 8 to 12 weeks and keep non-responders on your list, especially those planning a remodel.
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