Globally, building sector contribute highly to energy consumption and pollutant release in the form of 𝐶𝑂ଶ emissions. The share of housing in energy consumption increases as the residential construction sector is growing faster than other buildings sectors in Oman and other GCC countries. This high percentage of energy consumption and production not only raises the expense of building energy but also has a negative influence on the environment. Native population has adopted variety of techniques to improve thermal conditions in buildings. Courtyard, urban layout, wall thickness etc. are examples of such techniques. Among those techniques was the windcatcher which found in hot climates where it was necessary to cool the space. In this research, a computational fluid dynamics (CFD) tool is used to evaluate the airflow in the windcatchers under various parameters. Those parameters are the impacts of wind speeds and angles. In addition, different windcatcher designs were carefully examined for a traditional building. The findings of this study give windcatcher designers crucial knowledge on key design factors such as geometrical and environmental factors. It was found that a four-sided windcatcher is better compared to one-sided and two-sided windcatcher because of wind angles. Furthermore, squared windcatcher with an X-blade configuration is the optimum design for the studied location. In addition, blades can increase the average air velocity of the windcatcher by 42% in a southwest wind. Although the windcatcher in the traditional house was able to improve the Indoor Air Quality of the house, the 𝐶𝑂ଶ concentration is still high. However, adding more windcatchers in the house was able to reduce it by more than 70% and return it to an acceptable level. Moreover, adding a windcatcher in a modern house was able to enhance the thermal comfort, and reduce the 𝐶𝑂ଶ concentration. Results shows that a windcatcher constructed with an angle of 30 degree from the north able to increase the average air velocity inside the space more than windcatcher rotated by 0, 45, and 60 degrees. The difference between average air velocity inside the space without a windcatcher and within a windcatcher with a rotation of 30 was found to be more than 55%. Although that the windcatcher couldn't reach thermal comfort during the studied month, it was able to reduce the 𝑃𝑀𝑉௥௘ௗ by 6.9%, and the 𝑃𝑃𝐷௥௘ௗ by 10.7%. In addition, a windcatcher in a modern house was able to reduce the 𝐶𝑂ଶ concentration by 45% compared to a house without windcatcher.