1. What is Relative Humidity?

Relative humidity (RH) is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature). It is expressed as a percentage.

2. How Does the Calculator Work?

The calculator uses the relative humidity formula:

Where:

• \( w \) — Humidity ratio (kg of water vapor per kg of dry air)
• \( w_s \) — Saturation humidity ratio at the same temperature (kg/kg)

Explanation: The formula calculates what percentage the current humidity ratio is of the maximum possible humidity ratio at that temperature.

3. Importance of Humidity Calculation

Details: Relative humidity is important for comfort, health, industrial processes, and building design. It affects evaporation rates, human comfort, and material properties.

4. Using the Calculator

Tips: Enter both humidity ratio (w) and saturation humidity ratio (ws) in kg/kg. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between humidity ratio and relative humidity?
A: Humidity ratio is an absolute measure of water vapor content, while relative humidity is a percentage of the maximum possible at that temperature.

Q2: What are typical humidity ratio values?
A: Typical values range from 0.005 to 0.030 kg/kg in most climates, but can be higher in very humid tropical conditions.

Q3: How does temperature affect the calculation?
A: Temperature affects the saturation humidity ratio (ws). Warmer air can hold more moisture, so ws increases with temperature.

Q4: Why is 100% RH important?
A: At 100% RH, the air is saturated and can't hold more water vapor. Further cooling will cause condensation.

Q5: What instruments measure these values?
A: Hygrometers measure relative humidity directly, while psychrometers can calculate humidity ratio from dry-bulb and wet-bulb temperatures.