When taking temperature differentials the only thing being accounted for is sensible heat, depending on your location this can be high or low & not an indicator of the systems true performance.

What would be of true benefit is to take wet bulb temperature readings in addition to dry bulb readings.

With both of these readings & the known airflow moving over the evaporator you can determine the total, sensible & latent capacity of the equipment.

What really is an eye opener is to take these measurements at the equipment & then take them across the duct system to allow for losses.

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Measured Performance more than just a buzzword