Coil Selection Calculator

Sensible Heat Ratio is Sensible Capacity divided by Total Capacity, and both of those are calculated as CFM multiplied by a temperature-based factor. Since Airflow (CFM) appears as the same multiplier in both the numerator and denominator, it cancels out algebraically — SHR depends only on the entering and leaving dry-bulb and wet-bulb temperatures, not on how much air the coil is moving.

A lower SHR means a larger share of the coil's capacity is going toward removing moisture (latent cooling) rather than lowering temperature (sensible cooling). This matters in humid climates or high-occupancy spaces where dehumidification is a priority — a coil sized only from a sensible-load calculation could leave a space cool but clammy if the actual SHR need is lower than what the coil delivers.

Total Capacity is calculated directly from the dry-bulb and wet-bulb temperature drops using the coil's air-side enthalpy change, and Latent Capacity is then derived by subtracting Sensible Capacity from that total (floored at zero so it can't go negative). In other words, Total and Sensible are the two independently calculated figures, and Latent is the remainder — not the other way around.

Dry bulb temperature alone only captures sensible heat — the part of cooling that lowers air temperature. Wet bulb temperature reflects moisture content as well, which is needed to estimate the coil's total (sensible plus latent) capacity per standard AHRI 210/240 and AHRI 550/590 rating-condition methodology. Without wet bulb readings, the calculator can't separate how much of the coil's work is dehumidification versus temperature drop.