In HVAC, latent load is the moisture coming from people, cooking, showers, infiltration and outdoor ventilation air, and the coil removes it by condensing water. Latent Btu per hour is about 0.68 times cfm times the change in grains of moisture. Humid climates, crowded rooms and high ventilation rates all push latent load up, and oversized equipment that short cycles handles it badly.
Latent load in the gym spikes during a game, 600 people sweating, so the unit needs to run long and slow to pull that water out.
Also heard as
- latent
Related terms
Sensible heat
Heat that changes the air's temperature, which you can read on a thermometer.
SHR
Sensible heat ratio: the share of a cooling load or coil capacity that is sensible rather than latent.
Humidity ratio
The weight of water vapor per weight of dry air, usually given in grains per pound.
Dew point
The temperature at which air becomes saturated and water starts condensing out when it is cooled.