Mobile homes use a corrected airflow estimate of 300 CFM/ton due to undersized flex duct runs, belly-board routing, and single central returns. MERV 8 is treated as the practical ceiling for 1" filters. A 4" deep filter is strongly recommended wherever the slot allows it.
outdoor unit
On the data plate of the outdoor unit. Many model #s encode tonnage: "24"=2T, "36"=3T, "48"=4T
filter / return grille size
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Max recommended MERV
Change filter every
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Est. CFM
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Filter area ft²
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Face velocity FPM
all filter options for your system
MERV
Filter type
Purpose
Change interval
Status
Calculated using ACCA Manual D airflow standards and ASHRAE face velocity guidelines. Standard homes use 400 CFM/ton; mobile/manufactured homes use 300 CFM/ton. Actual airflow varies by blower speed, duct condition, and static pressure. A 4" deep MERV 8 filter almost always outperforms a 1" MERV 13 in both airflow and filter life. This tool is a guide — not a substitute for a static pressure test. For help call Mike's A/C at 985-516-3353.
