You can reduce load on the fan by increasing the number of filters. Arrange 2 into a wedge or 4 into a cube around the box fan and direct the airflow with cardb

You can reduce load on the fan by increasing the number of filters. Arrange 2 into a wedge or 4 into a cube around the box fan and direct the airflow with cardboard and tape. Worked great at our drafty place during the forest fires last summer.