Systems and methods for detecting various system conditions in a fluid delivery system (such as an HVAC system) based on a motor parameter are disclosed. Embodiments of the present invention relate to detecting: filter condition, frozen coil condition, register condition, energy efficiency, system failure, or any combination thereof. Embodiments of the present invention relate to detecting fluid delivery system conditions based on motor parameters including system current, system power, system efficiency, motor current, motor power, motor efficiency, and/or a change (or rate of change) in motor parameters. Techniques for responding to a clogged filter and a frozen coil are also disclosed. Also disclosed are techniques for characterizing a fluid delivery system off-site, prior to system installation.