Kashan is a splendid city. My only gripe is the relative lack of accommodations for tourists. Aside from a far flung hotel on the edge of town and a motel in the middle of the city where the bathrooms are located in the hallway there is really no place to stay. Then again, with the decline of tourism in Iran in general and lack of investors one cannot expect much.
Of the many attractions Kashan has to offer, the Tabatabei House and the Fin Gardens are a must see.
The Tabatabei House was built in the 19th century by Ostad Ali who was a famed architect of the time, and it represents the traditional dwelling of the affluent people of the time. The property has four major courtyards with their respective fountains, as well as stained glass windows and wall paintings which have survived to this day. At the time of my visit the house was being refurbished and restored by the Cultural Heritage Organization (Miras-e Farhangi). One of the interesting features of this house is the basement which is some 40 feet below ground level. This area provided for cool air during the scorching summer months and must have been delightful in an era devoid of modern comforts.
The Fin Gardens which most know as the place where Amir Kabir was murdered by Naser-idin Shah's henchmen, was actually built during the Safavid period. This desert oasis houses the Soleimani Brook which has been the lifeline of the lush gardens and cypress trees. The brook is connected to a series of pools and fountains that operate by gravity alone and is truly a stroke of genius. If you have a chance to see Kashan I highly recommend it.