| Unventilated | The PV module is installed without airflow behind it, leading to higher operating temperatures and reduced efficiency. Suitable for building-integrated systems (e.g., PV panels embedded in roofs or facades). |
| Moderately ventilated | Limited airflow is present behind the PV module, allowing some cooling but still leading to moderate temperature increases. Common in rooftop installations with a small gap between the panel and the surface. |
| Strongly or forced ventilated | Active airflow (natural or mechanical) is used to cool the PV module, reducing temperature and improving efficiency. Often used in large-scale solar farms or setups with cooling fans. |
| Rear surface free | The back of the PV module is completely open to airflow, maximising natural cooling. Typically seen in ground-mounted systems or open-rack installations. |