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Pressure drop of installing a merv 13 filter on a floor console mini split?

bfw577 | Posted in General Questions on

The stock 15 x 21 plastic filter on my floor console mini split is pretty terrible. You can see on the coil how much dust it lets through. A one inch 15 x 21 furnace filter appears to fit perfectly in the front filter cover without blocking any airflow inlets. This console runs basically 24/7 and it would be great to get better filtration.

The filter has the pressure drop on it and the submittal sheet list the cfm of the unit at 250/320/360 cfm from low to high. According to the filter the pressure drop would be .08 at 410 cfm. So lets assume my airflow averages around 300 so it would be less than .08 maybe more like .05? Is that going to be a lot of restriction? Seems pretty low to me and shouldn’t be an issue based on some quick internet research. A fiberglass filter is said to have around a .08 pressure drop. According to the service manual the fan speed isĀ  automatically regulated to the evaporator temperature and only uses 26 watts so increased fan electrical consumption is not a concern. The fan motor also is a resin packed brushless dc motor.

I know ducted units can utilize better filters on them. What kind of pressure drop to they see?

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  1. Expert Member
    Akos | | #1

    I've tried this with a wall mount, works but dropped the flow rate to 1/2 rated. This just means you can't get full power out of the unit, which was the reason I installed it.

    If you want full BTU, you might need to find a less restrictive filter, try to find a MERV5 pleated filter, if not a MERV8.

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