Knob and tube wiring when properly installed is not dangerous. In fact, this wiring method is superior, in some ways, to modern wiring procedures. Generally, the concerns surrounding its safety are the roughly same concerns that haunt dated wiring practices. The materials used in the original installations of knob and tube wiring are high in quality, but decades of usage, modifications by previous owners, and other factors have worn them down. This is where heritage home rewiring comes in. Heritage home rewiring has to be completed before old houses become livable. The amount of time and money needed to invest on heritage home rewiring depends on how extensive the rewiring needs to be. Some homes have knob and tube wiring systems that are undisturbed, and don’t require much rewiring work; expect to shell out a huge amount of money for houses whose wiring systems are not so easily accessible, though.