Insuring an older home with knob and tube wiring

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Knob and tube wiring is one of the most common reasons older homes get denied home insurance. Many insurers won’t offer coverage until it’s been upgraded to current safety standards, and those that do often charge higher premiums.

Found in many homes built before the 1950s, knob and tube wiring lacks a ground wire, so excess electrical current has nowhere safe to go—raising the risk of overheating, sparking, and fire. The insulation on these older wires can also dry out and crack over decades, leaving live conductors exposed. Insurers view this as a serious fire and electrocution hazard, which is why it so often blocks coverage.

Protect your wallet

Inspect before you buy or commit. A licensed electrician’s report tells you what you’re walking into — so a surprise rewiring bill doesn’t land after closing.
Disclose the wiring, always. Staying silent to keep your premium low backfires: an undisclosed system can void your policy, meaning you pay out of pocket for a loss you thought was covered.
Weigh $5,000–$10,000 now against years of inflated premiums. Keeping old wiring can cost 50% to 100% more per year in coverage—so replacement often pays for itself.
Don’t let the 30-day deadline cost you the loan. Miss an insurer’s upgrade window and they can cancel coverage and notify your lender, putting your mortgage at risk.

Why do some homes have knob and tube wiring?

Homeowners insurance companies see homes with knob and tube wiring as high-risk.

“This type of electrical system was prevalent prior to 1940 because it was less expensive to install than other types,” explains Kenneth Gregg, CEO of Orion180 Insurance Services, LLC, in Melbourne, Florida. “Knob and tube wiring contains only a live hot wire and a neutral return wire, versus modern-day wiring that includes a ground wire. The lack of a ground wire is a significant fire hazard.”

These homes also typically have an old-fashioned fuse box with ceramic and copper fuses that must be replaced when blown. Knob and tube fell out of favor as homeowners needed more power for refrigerators, air conditioners, TVs, computers, and other modern electronics.

Why do insurers consider knob and tube wiring a fire risk?

Knob-and-tube wiring lacks a ground wire, so excess electrical current has nowhere safe to go — raising the risk of overheating, sparking and fire.
Be aware that the insulation on these older wires can dry out and crack over time, leaving live conductors exposed.
Check with your insurer early: many providers require homeowners to replace outdated wiring before they’ll approve coverage.
Budget accordingly: rewiring an older home runs between $5,000 and $10,000 or more, depending on the size and layout of the property.

Why is knob and tube wiring a concern for insurance companies?

Older residences with knob and tube wiring can frequently overload, posing a fire hazard because of the power demands of today’s homes.

“As many older homes have undergone renovations, knob and tube wiring is now often covered with insulation and pushed into close contact with other building materials, resulting in a major fire hazard,” Friedlander cautions.

Additionally, the original insulation of these wires can fail over time, with the copper becoming exposed.

Exposed wiring poses serious risks, including fire and electrocution hazards. Unlike modern circuit breaker boxes that can simply be reset after a power surge or overload, older systems require replacing a blown fuse with the right type — which can be tricky to find these days.

Can I get homeowners insurance with knob and tube wiring?

It’s tough. Most insurers won’t cover a home with knob and tube wiring unless you agree to upgrade it — usually within 30 days of purchase. Mortgage lenders often require the same. If you miss that deadline, your insurer can cancel your policy and notify your lender, which may put your loan at risk.

Some insurers will still consider you, but only after an inspection. As Friedlander puts it, they’ll want to check “the condition and functionality of the wiring before an underwriting decision can be made.”

And even if no one asks about your wiring, you have to disclose it. “Failure to do so would constitute serial misrepresentation and would invalidate your homeowners insurance policy in the event of a claim,” warns Gregg.

Your options if you don’t upgrade

If you’re not planning to rewire, expect fewer choices and higher costs. You’ll likely need one of these:

A specialty or excess-and-surplus insurer, which Gregg says will cover the home but “at a significant extra cost in premiums.”
An HO-8 or modified form policy, designed for older homes.
Limited coverage from a niche insurer — though many companies won’t offer any coverage at all.

Choosing the right policy

If you do find a willing insurer, look for an extended or guaranteed replacement cost policy. It pays a set percentage — often 20% or more — above your coverage limit to rebuild. “This way, if building costs go up unexpectedly… you’ll have extra funds to cover the bill,” says Friedlander.

Just know that without a wiring upgrade, a standard replacement cost policy may be off the table. You may have to accept a modified version, which pays to rebuild with today’s standard materials rather than matching older features like plaster walls or hardwood floors.

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What can you do if you can’t get home insurance because of knob and tube wiring?

In order to get insurance for your home, you have to update the wiring system to a safer option. Once you have done that, you can have comprehensive coverage to protect your home.

“By replacing knob and tube wiring with modern electrical wiring, you are creating a much safer environment for your family and preventing many unnecessary risks,” says Friedlander. “The other major benefit is you will be able to purchase standard homeowners insurance coverage and not pay an excessive premium because of your home’s antiquated wiring.”

Why do insurers see older homes as a higher risk?

Insurers see older homes as higher risk because they come with older systems – and they are more likely to fail and very expensive to repair. Outdated electrical wiring, older plumbing and worn out roofing all increase the chances of a claim — and the cost of one.

Plumbing and pipes

Homes built before the 1960s often contain galvanized steel or even lead pipes that can corrode or leak over time. Many insurers require homeowners to update these systems with copper or PEX before providing full coverage. Upgrading your plumbing not only improves safety but can also lower your premium.

Roof condition and materials

Your roof’s age and construction play a major role in your insurability. Older roofs—especially those made from wood shake, slate, or tile—may not meet current safety standards and can be expensive to repair. Insurers sometimes offer only actual cash value coverage for roofs more than 20 years old unless they’ve been recently replaced. A new or reinforced roof can make your home more attractive to insurers.

Outdated or specialty building materials

Historic homes often feature plaster walls, intricate trim, or other high-cost materials that are difficult to replace after damage. Because of this, insurers may cap coverage or issue a modified replacement cost policy that accounts for these specialized materials.

How to keep your policy affordable

Updating your home’s electrical, plumbing, and roofing systems can greatly improve safety and reduce insurance costs. Keep inspection reports and document every upgrade — it shows insurers your home meets modern safety standards and may qualify you for better coverage and lower rates.

Frequently asked questions about knob and tube wiring

How much does it cost to replace knob and tube wiring?

You can expect to pay at least $5,000 to replace knob and tube wiring depending on the size of your home. The cost may exceed $10,000 depending on the work and repairs by a licensed electrician.

If you were to keep the old wiring and find an insurer to cover you, expect to pay between 50% and 100% more per year for insurance coverage than an updated home with modern electrical components due to the high underwriting risk, Friedlander says.

Is knob and tube wiring a fire hazard?

Yes, knob and tube wiring can present a major fire and electrocution threat.

Many homes with older electrical systems are remodeled. This old wiring is often covered with insulation and pushed into close contact with other building materials, resulting in electrical fires.

Also, the original insulation of these wires can fail over time, with the copper becoming exposed.

Should you buy a house with knob and tube wiring?

You may still want to purchase a home with knob and tube wiring, especially if it has architectural features and historic charm you value.

But the experts agree: You will need to protect these homes for your own use and future generations by updating important systems and components like:

Electrical
Plumbing
HVAC
Foundation
Roof

In fact, your insurer and mortgage lender may require those upgrades.

“Make sure you have the right insurance coverage in place and a good team of remodelers and repair professionals to help you along the way,” recommends Brian McCabe with Provision Insurance Group.

Is knob and tube wiring legal?

Local building and electrical codes can vary. However, it’s likely not against the law to have a home with knob and tube wiring systems in your area.

The problem is that home insurance companies and mortgage lenders won’t tolerate this kind of electrical system.

The home likely won’t pass a professional home inspection that lenders often require. You’ll then be required to convert to modern electrical service.

Erik Martin

Contributing Researcher

Erik J. Martin is a Chicago-based insurance expert and journalist with 27 years of experience covering insurance, personal finance and real estate. He helps consumers understand complex financial topics—from choosing the right car insurance policy to managing household budgets—through clear, practical guidance.

On this page

Why do some homes have knob and tube wiring?
Why is knob and tube wiring a concern for insurance companies?
Can I get homeowners insurance with knob and tube wiring?
What can you do if you can't get home insurance because of knob and tube wiring?
Why do insurers see older homes as a higher risk?
How to keep your policy affordable
Frequently asked questions about knob and tube wiring

Home insurance for older homes with knob and tube wiring

Why do some homes have knob and tube wiring?

Why is knob and tube wiring a concern for insurance companies?