Senior Bhutanese engineer Dorji from Wachen village under Wangdue Phodrang district explains the ventilation systems that are commonly found in traditional Bhutanese houses. Ventilation in Bhutanese houses can be of two types: Galkar (Dzo. rgyal dkar), the smaller ventilation, and Payap (Dzo. par gyab), the bigger ventilation. Dorji explains that the smaller ventilation system comprises two sets of windows, and the bigger one comprises three windows. Both are design to help in the circulation of fresh air inside the house, and to be aesthetically pleasing.