Calculate the density of moist air based on altitude, temperature, and humidity. Essential for aerodynamic and HVAC fluid flow corrections.
As altitude increases, atmospheric pressure decreases, causing the air density to drop. Thinner air requires larger fans or ducts to move the same mass of air.
Counter-intuitively, humid air is less dense (lighter) than dry air at the same temperature and pressure, because water molecules are lighter than nitrogen and oxygen molecules.
Standard air density is typically defined as 1.204 kg/m³ at 20°C (68°F) at sea level with 0% relative humidity.
Air density directly affects lift and drag. Aircraft perform completely differently on a hot, humid day at high altitude (low density) compared to a cold, dry day at sea level (high density).