Yeah, you can just as easily make it a puller design. I made mine not long ago, simply taped a MERV13 4" filter to the back of a 20x20 box fan. Works like a cha

Yeah, you can just as easily make it a puller design. I made mine not long ago, simply taped a MERV13 4" filter to the back of a 20x20 box fan. Works like a charm, no dust getting pushed off the filter.