Nowadays, providence of non-renewable energies is the most important issue of Iran. Iranian architects have focused on two approaches of energy saving. Firstly, they are going to use past architecture experiences and secondly, they use new scientific solutions. This paper among the traditional cooling systems, studies pool houses. They have been used in different locations of Iran; although they are similar, in general but their structure differs with the climates. This paper is going to answer some questions: Are pool-houses passive cooling systems? Are there different pool-houses in various regions of Iran? The research method is descriptive-analytic and we have collected some data and information through library and field study.  We studied pool-houses in different climate conditions of Iran; we found that pool-houses have different structures. For instance, in north-west Iran, where the climate condition is cold, they are located at basement of two-story buildings, and there is not a roof ventilator.  But in warm and dry areas they use Khyshkhan on the roof for wind circulation and subterranean-water is accessible in some houses.