Dew Point Calculator
Calculate the dew point temperature from air temperature and relative humidity, or calculate relative humidity from air temperature and dew point temperature. This tool is essential for HVAC professionals, meteorologists, and industrial applications where moisture control is critical.
Dew Point Comfort Levels
- Below 10°C (50°F): Very dry, may feel uncomfortable for some
- 10-16°C (50-60°F): Dry and comfortable
- 16-18°C (60-65°F): Comfortable for most
- 18-21°C (65-70°F): Slightly humid
- 21-24°C (70-75°F): Humid and uncomfortable
- Above 24°C (75°F): Very humid and oppressive
Humidity Comfort Levels
- Below 30%: Very dry, may cause discomfort
- 30-50%: Comfortable for most people
- 50-60%: Slightly humid
- 60-70%: Humid, may feel uncomfortable
- Above 70%: Very humid and oppressive
Calculation Results
Dew Point: 14.0 °C
At 25°C and 50% humidity, the dew point is 14.0°C. This is in the comfortable range for most people.
About Dew Point and Humidity
The dew point is the temperature to which air must be cooled to become saturated with water vapor. When cooled further, the airborne water vapor will condense to form liquid water (dew). Understanding dew point is crucial for various applications including meteorology, HVAC system design, industrial processes, and even determining human comfort levels.
How Dew Point is Calculated
The dew point temperature is calculated using the Magnus formula, which relates the saturation vapor pressure of water to temperature:
Magnus Formula for Dew Point Calculation
For temperatures above 0°C:
γ(T,RH) = ln(RH/100) + (bT)/(c+T)
Td = (cγ(T,RH))/(b-γ(T,RH))
Where:
- T = air temperature in °C
- RH = relative humidity in %
- Td = dew point temperature in °C
- b = 17.67 (constant)
- c = 243.5°C (constant)
Applications of Dew Point Measurement
HVAC Systems
Dew point is critical in designing heating, ventilation, and air conditioning systems. It helps determine when condensation will occur on cooling coils and surfaces, which is important for preventing mold growth and maintaining indoor air quality.
Meteorology
Meteorologists use dew point to predict fog, frost, and precipitation. The closer the dew point is to the air temperature, the higher the relative humidity, and the greater the chance of precipitation or fog formation.
Industrial Processes
Many industrial processes require strict control of moisture levels. Dew point measurement is used in painting, pharmaceutical production, food processing, and compressed air systems to ensure product quality and process efficiency.
Understanding the Results
The dew point calculator provides two main functions:
- Calculate Dew Point from Temperature and Humidity: Enter the air temperature and relative humidity to determine the dew point temperature.
- Calculate Humidity from Temperature and Dew Point: Enter the air temperature and dew point temperature to determine the relative humidity.
The comfort level indicators help interpret the results in terms of human comfort and potential for condensation problems in buildings.