Can airconditioning be installed in house with knob and tube wiring?

Knob and tube is less of an issue than the capacity of the electrical system. Typically, older homes did not have wiring that would handle the current capacity of modern electrical needs. In fact, many of the older knob and tube homes did not even have 240 V service.

Contact a local electrician to determine the capacity of your home and the electrical needs of the AC system.