I was browsing through some old home improvement books at a thrift store when I came across a reference to knob-and-tube wiring. This sparked my curiosity, as I had never heard of this type of electrical wiring before. As I researched further, I learned how this long-forgotten wiring method from the late 1800s could potentially save me thousands on my energy bill if utilized in my home.

What is Knob-and-Tube Wiring?

Knob-and-tube (K&T) wiring was commonly used in homes and buildings in the United States from about 1880 to the 1940s. It consists of insulated copper conductors that are run through ceramic knobs mounted to framing members and ceramic tubes to protect wires where they pass through walls, floors, and ceilings.

Some key features of knob-and-tube wiring:

K&T wiring has largely been phased out and most homes today use plastic-insulated cables like NM, also known as Romex wiring. But K&T can still be found in many older homes.

Why Knob-and-Tube Wiring Is More Energy Efficient

The open air spaces and breathability of knob-and-tube wiring make it much more energy efficient compared to modern NM cables. Here's why:

By keeping wires cooler and allowing heat to dissipate faster, K&T wiring avoids energy loss through heat buildup. My local electrician confirmed that knob-and-tube systems can use 3-5% less electricity than modern wire cables.

How to Take Advantage of Knob-and-Tube Wiring

If your home has existing knob-and-tube wiring, here are some ways to utilize it for maximum energy savings:

Leave Undisturbed Wiring in Place

Insulate Around Wiring

Upgrade Electrical Load

Address Unsafe Wiring

Real-Life Example: Bob's K&T Wiring Retrofit

My neighbor Bob took advantage of existing knob-and-tube wiring when he renovated his 1920s home. Here were the steps Bob followed:

The Bottom Line: Don't Overlook Old Knob-and-Tube Wiring

Knob-and-tube wiring may seem antiquated, but it can be an untapped source of energy savings in older homes. As Bob discovered, working around existing K&T and using a targeted upgrade approach can allow you to gain efficiency benefits from this old wiring method. With some upgrades and insulation, those ceramic knobs and tubes can potentially save thousands on your energy bill over time.