Understanding the Basics of Humidity

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High humidity makes normal days feel like an oven. This only makes home and business owners set their thermostats lower, inducing stress on their AC units to produce cooler air. As a side effect, it also increases your power bills for low gain, and you might even wonder why your air conditioner isn’t doing as much.

Before you begin contacting your nearest AC service professional, take heed. Draper is not as humid as other parts of the country (unlike Orlando, FL for example, with a whopping 74% average compared to the former’s 44%), but you can still control it and see significant gains on your cooling goals. Still, it’s a good idea to have a refresher on why and how exactly humidity contributes to the feeling of heat, called the heat index. To do that, you should consider how humidity is measured.

Humidity Levels: Absolute and Relative Humidity

Humidity is defined as the amount of water vapor in the air, but it doesn’t tell you much. This is why there are two ways to measure how much humidity is in the air and how it affects you: absolute humidity (AH) and relative humidity (RH). As you might expect, absolute humidity deals with a more objective measurement; it’s the ratio of the amount of water vapor with the dry air of a specific volume at a given temperature.

On the other hand, relative humidity—shown in %— is more relevant to the discussion. “Relative,” in this case, because it uses a comparison between the current absolute humidity versus the highest possible absolute humidity in a specified region. For example, relative humidity of 50% means the air in that area holds 50% water vapor at that temperature.

Dew Point

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Warm air can hold more water vapor than cold air. If you cool it enough to the point of 100% relative humidity, water vapor will start to condense or turn to liquid again. This is called the dew point. This is what happens when you go outside after a cold night, and you stumble upon water droplets on the grass on your lawn or yard. You can also see it in action when you leave a cold glass of water outside the refrigerator.

That means the higher the dew point is, the more uncomfortable it will become. As a result, higher temperatures combined with higher dew point means your sweat won’t evaporate as quickly, and you’ll be stuck with a soaked T-shirt. A dew point of 50-55 is comfortable enough, but more than this and it starts becoming harsh.

What You Can Do

A dehumidifier can do the trick, although some units come in a combo (it can both humidify and dehumidify). Ask your AC service technicians about dehumidifier retrofits to your existing AC system if it can accommodate it. Such a system can help you whatever season as it can stabilize relative humidity in both summer and winter.

Like most things, humidity can be both good and bad, but in terms of air conditioning, it’s more of the latter. Understanding it and how it can be controlled is an excellent first step in getting the most out of your AC unit.




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