: It is industry standard to add a 10% safety margin to your final number to account for installation variances. Practical Example Pressure Loss (in. w.g.) Straight Duct 150 ft @ 0.1/100 Fittings 5 Elbows (eq. 75 ft) Filters Standard pleated Diffusers Subtotal 0.475 Total (w/ 10% Safety) 0.523 Why Getting it Right Matters ESP Calculation for HVAC Ducts | PDF - Scribd
: External filters or coils not built into the primary unit. The Step-by-Step ESP Calculation esp calculation for duct
$$ \textTotal ESP = \textSupply Loss (0.36) + \textReturn Loss (0.20 est.) + \textSafety Factor $$ : It is industry standard to add a