Lijan Greentech is Manufacturer and Supplier for Different Types of Roof Ventilator Fans. We do both Supply and Installation. Roof Ventilator Fans Helps to Reduce Heat Inside Buildings and Ensure Ventilation. Wind Energy is Used in Turbo Roof Ventilator Fans. 22", 24" and 25" are Most Common Throat Size of Roof Ventilator Fans. Number of Roof Ventilator Fans to be Installed is decided by Volume of Building, Working Conditions in Building, Average Wind Speed in the Locality and Capacity of the Ventilator Fan. As a thumb rule, one 22" Ventilator Fan is Sufficient for 500 ft2 Floor Area in Normal Conditions. Installing Ventilators Perpendicular to Floor Level Increases Life of Fans. Many Roof Ventilator Fans are Found Rotating Slowly or Stop Due to Faulty Installation. Lijan Greentech have Professional Experienced Service Team for Installation of Roof Ventilator Fans. We do Installation with Warranty.