First, solar fan should be installed on an unobstructed sunny roof. Check for any shade on the roof created by trees, chimney, or satellite dish.
Secondly, the fan should be installed as close to the ridge (high place) as possible to obtain the best ventilation effect. Please close any vent near your fan.
The best installation angle is when the highest temperature in summer (usually at 2-3 o'clock in the afternoon), the output power of the solar panel reaches its peak, and the sun shines on the solar panel vertically.