Humidity has a large role in climate and climate control along with temperature. Most people recognize humidity as moisture or dampness in the air. It is basically the amount of water vapor molecules in the air.
Humidity may also be measured in many different ways, Absolute humidity is the volume of water vapor in the air. Specific humidity is the mass of water in the air. Relative humidity is the amount of vapor in the air to the amount it might hold when saturated shown as a percentage. For example (RH%)=65%. Relative humidity has the phenomenon of decreasing when temperature increases while the actual quantity of water vapor stays the same.
It’s often relative humidity that is referred to in climate control, weather forecasts, buildings and enclosed spaces, health and safety etc.
Associated with relative humidity is dew point, dew-point is when temperature can’t hold the water vapors any longer, the vapors then condense into liquid, at which point it is 100% relative humidity. Both dew-point and real temperatures are the same at this point. Therefor a change in temperature will cause a change in humidity.
Humidity and temperature are the main environmental reasons which causes decay and deterioration, timbers rot, metals corrode, textiles fade and deteriorate more quickly, Insects and molds generally like a warm damp environment. These affects gives reason to the importance of climate control in buildings, structures and our environment.
Humidity can be measured with a hygrometer or psychrometer, but generally with high levels of dryness or dampness in the environment, you can feel it on your skin. Humidity can be controlled with a humidistat (humidity controller) this is what is used to regulate the humidity independent of temperature even though both have an effect on each other.
Humidifiers and dehumidifiers are generally used to control relative humidity. Humidifiers introduce moisture into the air by using either a steam generator or an ultrasonic humidifier. A dehumidifier is basically an air-conditioner although it can be used in reverse for heating; moisture from the air is condensed on the cooling coils, and removed with a hose or collected in a bucket.