If you own an older home in the Pittsburgh region, there’s a good chance you’ve heard of knob and tube wiring.
And if you’re thinking about selling, it’s something you need to understand before you list.
What Is Knob and Tube Wiring?
Knob and tube wiring (often called K&T) was a common electrical system used in homes built roughly between the 1880s and 1940s.
It gets its name from:
-
Ceramic knobs that support wires along framing members
-
Ceramic tubes that protect wires passing through wood framing
At the time, it was a safe and innovative system.
But electrical demands today are very different than they were 100 years ago.
Why Is It Common in Western Pennsylvania?
Western Pennsylvania has a large inventory of older homes — especially in neighborhoods built before 1950.
Many of these homes:
-
Have been partially updated over time
-
Have modern wiring in kitchens and bathrooms
-
Still contain some active knob and tube in attics, upper bedrooms, or light fixtures
It’s not unusual for heavy-use areas to be upgraded, while low-use areas remain untouched.
Why Is Knob and Tube a Problem When Selling?
The biggest issue isn’t always safety — it’s insurance.
Today, most insurance companies:
-
Will not insure a home with active knob and tube wiring
-
Or will decline coverage if more than 5% of the home’s electrical system is still active K&T
-
Or may charge significantly higher premiums
If a buyer cannot secure homeowners insurance, their lender will not allow the loan to close.
That means even if you find a willing buyer, the deal can fall apart late in the process.
Is All Knob and Tube Dangerous?
Not necessarily.
Knob and tube itself is not automatically unsafe if:
-
It has not been altered improperly
-
It is not overloaded
-
It is in good condition
However, concerns arise because:
-
It lacks grounding
-
It may have deteriorated insulation
-
It was not designed for today’s electrical loads
-
It is often mixed with modern wiring
The issue is less about panic and more about compatibility with modern standards — especially insurance underwriting requirements.
What Sellers Should Do Before Listing
If your home was built before 1950, it’s wise to:
1. Get a Pre-Listing Electrical Evaluation
Hire a licensed electrician to:
-
Determine if knob and tube is still active
-
Estimate the percentage of active wiring
-
Provide documentation of upgrades
2. Consider a Pre-Inspection
A pre-listing home inspection can:
-
Identify electrical concerns early
-
Allow you to price strategically
-
Prevent surprises during buyer inspections
3. Disclose Honestly
If knob and tube exists:
-
Disclose it properly
-
Provide documentation of upgrades
-
Share any electrician reports
Transparency builds trust — and avoids legal risk later.
Should You Replace It Before Selling?
That depends on:
-
How much of the home still uses it
-
Your price point
-
Your timeline
-
Insurance market conditions
If more than 5% of the home is still on active K&T, replacement may be necessary to avoid insurance problems during escrow.
In some cases, partial replacement is enough. In others, a full upgrade is the smoother path.
Final Thoughts
Knob and tube wiring is common in Pittsburgh’s older homes — and it doesn’t automatically make your house unsellable.
But in today’s insurance environment, it can absolutely affect your ability to close.
The smartest move isn’t to panic.
It’s to prepare.
If you’re considering selling in the next 6–12 months, having your electrical system evaluated early gives you options — and options protect your negotiating power.
Preparation isn’t just helpful — it’s powerful.
