For FJM systems, enter only the line length from the outdoor unit to the individual indoor unit.
Note that FJM systems do not require any additional refrigerant charge due to the system piping length, however the app will still check that the line length is within the allowed length limit.
Room Area
For Ducted models using an RDS, enter the total floor area of all spaces connected to the ductwork
For Ducted models not using an RDS, enter the floor area of the smallest room on the system ductwork
Height Input Notice
According to ASHRAE standards, there are upper-and lower-limits for calculations:
For ducted models, the space height used for calculations may not exceed 9.0 ft.
For non-ducted models, the installation height used for calculations may not exceed 9.0 ft.
For console units or underfloor ductwork, the height used for calculations must not be less than 2.0 ft.
If a value outside these limits is entered, it will be automatically adjusted to comply with these guidelines. Refer to ASHRAE 15.2-2024, Table 9-3, note a.
Values below 2.0 ft will be set to 2.0 ft.
Values above 9.0 ft will be set to 9.0 ft.
New Caculation
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Calculation Breakdown
Where M is determined from Table 9-3, based on whether circulation (e.g., RDS) is present or not.