Understanding Humidity
No doubt, we’re aware of humidity when it is here in the El Paso area. But why do we feel it so much and why does it makes us so uncomfortable here? Here’s a quick look at why humidity makes some days feel hotter than usual and how it affects your comfort.
Even if you already have some understanding of what humidity is, this brief explanation may help you understand why managing your home’s humidity is one of the most important ways you can keep your living space healthy and comfortable. Here’s what you should know:
We don’t see it happening, but under almost all normal atmospheric conditions, some volume of a mass of water evaporates and condenses in a constant cycle.
When humidity is present, there is more water vapor in a given area and in the air. Water vapor is different than liquid water (liquid water is essential for all life: drinking, bathing, etc.). Water vapor doesn’t seem like it’s useful for much of anything–other than making you uncomfortable. But, believe it or not water vapor or evaporation and humidity serve a critical function of the natural world. We couldn’t do without it. When liquid water evaporates into gaseous water vapor, it has completed nature’s way of distributing water to things that need it: clouds, lands, trees, plants, animals, etc. If water didn’t evaporate, we wouldn’t have clouds, and it would never rain.
There are 3 kinds of humidity: Absolute Humidity, Dew Point, and Relative Humidity.
Absolute humidity is simply the total mass of water vapor in a given volume of air, regardless of the temperature of that air. In scientific terms, it’s the most “accurate” measurement of humidity, since the amount of water vapor in air directly determines humidity.
The Dew point is the temperature the air must be for water to condense and evaporate at the same rate. If the air temperature matches the dew point, then the air is exactly as saturated as it can be without condensation forming. Dew drops can be seen.
Relative humidity is a percentage measurement of water vapor saturation relative to maximum saturation. In other words, relative humidity measures how close the air temperature is to the dew point. 100% relative humidity means the air temperature has reached the dew point.
So, how does any of this explain why you feel so comfortable when humidity is in our forecast?
When the air is saturated with water, like on a humid day, evaporation is much slower. The air is already full of water, and can’t hold much more.
Your body will sweat in an attempt to cool itself. You will end up wet and hot the more humid it is because evaporation won’t be able to keep up with the water vapor in the air.
The point at which the air will begin to feel warmer is when the air temperature is about 77 degrees, and the dew point temperature is at or above 57. That’s what meteorology says anyway. The best way to think of dew point is that it is the temperature at which dew would form. The closer the air temperature is to the dew point, the more humid the air.
(Remember: low humidity will make the air feel cooler. For example, if the air temperature was 100 degrees, with a dry dew point of 25, the heat index would only be 93. This type of hot dry air is common here in El Paso).
With the rains bringing lots of humid air coming to our area later this week, you may feel a bit uncomfortable, especially if you don’t have refrigerated air. Evaporative coolers actually perform best in hot, dry air. When humidity enters the area, these coolers create compounded discomfort at home because they actually multiply air vapor and put out more humidity.
New refrigerated air systems are designed to perfectly balance humidity in the home. And, they do it automatically. For the ultimate in comfort at home, refrigerated air is the best cooling system you can have.
Total Air provides a free estimate for new refrigerated air systems. Call to get your free estimate at 915-585-0909 or schedule it at www.totalairep.com.
