A cased coil comes pre-installed in a factory-insulated metal cabinet that is designed to match the dimensions of your furnace perfectly. This makes installation much faster and ensures a professional, airtight seal within your Ducted system. In contrast, an uncased coil is just the raw evaporator coil without the outer box, which is often used in custom ductwork or tight spaces where a standard cabinet won't fit. When shopping for AC Coil Systems, choosing a cased model is generally recommended for Mobile Home Air Handler replacements to prevent air leaks. The casing also provides better protection for the sensitive aluminum fins during shipping and installation. Many ACIq coils offer a choice between the two based on the specific needs of your HVAC contractor. While uncased coils are slightly cheaper, the extra labor required to build a custom plenum usually offsets the savings. Always ensure your coil choice matches the tonnage of your Mobile Home Complete System.