The dangers of outdated wiring
Q: Our house needs insulation badly, but has knob & tube wiring (it's a 1920's house). How important is rewiring before insulation?
A: Very. Bill Ellison, owner of Ellison Electric in Greenfield, Indiana, says that "knob and tube wiring has a requirement of 3 inches of clearance around the wires for ventilation. This doesn’t leave very much room for insulation." If you put the insulation too close to the wires, they can overheat and cause a fire. "It can be costly to replace all of the wiring – depending on the size of the attic it can cost anywhere from $500 to $2,000," Ellison says. Although it is the most expensive type of wiring repair, it is really important to find a skilled electrician to do the work. "Since it is an older type of wiring, not everyone knows how to replace it," he says.