We spent 12 hours of researching and testing to find the best window fans for bringing in cool air at night or extracting hot air out of a kitchen window. For most people, the Pelonis 9″ Twin Window Fan is a great value. But the pricier Bionaire Twin Reversible Airflow Window Fan is worth an upgrade if you need more power or less noise.
Source: Gizmodo – The Best Cheap Window Fans