I recently just heard of attaching a MERV13 filter to a box fan. It would make sense that the 5 filter box design would potentially make the filters last longer, but I wonder if it’s actually more effective at filtering the air than a single filter attached to the back of the fan.
In theory, it would have the same effectiveness as a single filter as a given parcel of air will only pass through a single filter with both designs. To increase the effectiveness of the filtering, you would need to place the filters in series, ie. have two (or more) filters on the back of the fan. However, this would increase the resistance of the filter block and the fan would operate at a lower flow rate. So there’s a trade-off between effective air filtering and effective air flow.
I recently just heard of attaching a MERV13 filter to a box fan. It would make sense that the 5 filter box design would potentially make the filters last longer, but I wonder if it’s actually more effective at filtering the air than a single filter attached to the back of the fan.
In theory, it would have the same effectiveness as a single filter as a given parcel of air will only pass through a single filter with both designs. To increase the effectiveness of the filtering, you would need to place the filters in series, ie. have two (or more) filters on the back of the fan. However, this would increase the resistance of the filter block and the fan would operate at a lower flow rate. So there’s a trade-off between effective air filtering and effective air flow.