Q = 1.08 × CFM × ΔT (sea level)Where:
· Q = sensible heat (BTU/hr)
· 1.08 = 0.244 BTU/lb·°F × 0.075 lb/ft³ × 60 min/hr
· CFM = supply airflow
· ΔT = Room Temp − Supply Air Temp (°F)
At elevation, 1.08 is reduced proportionally to air density. At 5,000 ft ≈ 0.90.
This supply air temperature calculator works the sensible heat equation in any direction. Pick what you want to solve for — supply air temperature (SAT), room temperature, airflow, or sensible load — enter the other three quantities, and the tool returns the answer along with the room-to-supply temperature difference and the altitude-corrected sensible factor.
It is useful for checking a design supply air temperature, finding the airflow a coil must deliver to meet a sensible load, or back-calculating a room temperature from measured conditions. An elevation input corrects the sensible factor for air density so results stay valid above sea level.
| Sensible heat | Q (BTU/hr) = 1.08 × CFM × ΔT |
| Supply air temp | SAT = Room − Q ÷ (1.08 × CFM) |
| Required airflow | CFM = Q ÷ (1.08 × ΔT) |
| Sensible factor | 1.08 = 0.244 · 0.075 · 60 (sea level) |
The sensible heat equation is the standard airside relationship in ASHRAE Fundamentals. The constant 1.08 is the specific heat of air (≈0.244 BTU/lb·°F) × standard density (0.075 lb/ft³) × 60 min/hr, and ΔT is room dry-bulb minus supply dry-bulb. At elevation the factor is scaled by the barometric pressure ratio (1 − 6.8754×10⁻⁶·ft)⁵⋅²⁵⁵⁹, falling to about 0.90 near 5,000 ft.