I was wondering, what is the best way to model HVAC equipment for an already existing building? Is it better to select autosizing and let EnergyPlus to do the job OR entering all the data from manufacturers' manuals? Hardsizing will also include getting the coefficients for boilers, VRF system, heat recovery elements etc.
If Autosizing and using default equations/coefficients is the answer then will it make calibration a challenging task to perform?