I am sure you’ve heard the expression, it’s not the heat it’s the humidity. Let’s stop and think about humidity for a moment. Picture if you will a January afternoon, it’s 76 degrees and the humidity is sitting at 52%, got it? Now fast forward to a July morning. It’s the same 76 degrees however the humidity is sitting at 89%. That July morning certainly feels a lot hotter than the January afternoon correct?
Okay, so by definition what is humidity? According to Webster’s “Humidity is a quantity representing the amount of water vapor in the atmosphere”. The higher the amount of moisture that is suspended in the air the greater the humidity percentage becomes. So why do we feel hotter on days that are more humid? Let’s delve into that by looking at the science of the human body. I also want to take a look at some of the options we have when it comes to controlling humidity in our interior environments.
We can all agree the human body is amazing and that goes for the built-in cooling system we humans have. When our bodies heat up due to temperature our pores open and we secrete salt and excess water in the form of sweat. On days that the humidity is lower the air is able to absorb our perspiration much quicker, drying our bodies and allowing us to stay cooler. As the air surrounding us becomes more humid the atmosphere’s ability to absorb moisture decreases, thus we retain more sweat, which in turn makes us feel hotter. If you want to take a little deeper look at why we are hotter when it is more humid, and some personal cooling options read the answer from MIT.
So, what can we do to help control humidity inside, especially when it is so humid here in the Sunshine State so much of the time? The first thing is to make sure the air conditioning system for your home is sized properly. You will need to rely on a HVAC professional to ensure proper sizing. Remember, if an AC system is too small obviously it will not cool the space correctly, if it is too large it will not properly dehumidify the space. Air conditioners are not dehumidifiers by nature, however, good dehumidification is a nice by-product of a properly sized unit.
If you are shopping for an air conditioning system I strongly suggest you look at variable speed air handlers or indoor equipment. If the new AC system you have chosen has a variable speed fan motor the air is going to be moving just a smidge slower than it would be with a traditional motor. This in turn allows the air to spend more time on the indoor coil thus removing more moisture.
Next up, we can consider installing an actual dehumidifier in extreme cases. I typically find in larger homes with lots and lots of windows and high ceilings we face humidity issues not usually found in smaller homes. The way a dehumidifier works is very simple, it heats the air to dry it out. The unit typically heats the air to between 110-120 degrees.
Our dilemma in the industry here in South Florida is what do we do with all that hot air after we have dried it out? The answer lies in having a correctly designed duct system if you are thinking of having dehumidification installed. In an ideal situation we can wire the air handler and dehumidifier in series to run together and the air coming out of the dehumidifier is dumped back into the return air stream of the air handler so it is cooled before entering the home. We can also use dehumidifiers in attics to dry them out. It is not uncommon to find attics with very high humidity levels especially if the home has a lot of water features or is located near the ocean. By lowering the humidity in the attic, it reduces the load on the ducts in the attic as well as making the home easier to cool.
Alright kids, this concludes today’s diatribe on humidity. I hope you learned something and will join me next time for more helpful homeowner tips. Until then, I was thinking an interesting fashion statement would be a belt made from watches until I realized it was just a waist of time!
House Whisperer out!!
For Immediate Emergency Assistance Call 1-800-475-1504