I found few threads here about how to calculate air to water heat pump COP, but how do I do it for air to air?
I guess I would need mass air flow sensor, but, how exactly to to measure and calculate?
I haven’t done it, but… . I would start with temperature probes on either side of the blower, a couple feet either side for delta T. There are hot wire anemometers, measure the flow in the duct, maybe in the return side. Measure the airflow profile across the cross section of the duct, at each blower speed.