@dedrie77 @xuchuanmei @Kenneth33071904 @AnnieOddly @carolbinks @DrAimeeGrant You can buy smaller filters, for example 12x12. The problem is finding a 12x12 box fan. Not as common as the 20x20 ones. People have rigged things up with round fans and extra cardboard.
@dedrie77@xuchuanmei@Kenneth33071904@Annieodly@carolbinks@DraimeGrant您可以购买更小的过滤器，例如12x12。问题是找到一个12x12机箱风扇。不像20x20那样常见。人们用圆扇子和额外的纸板把东西装好。