MYTH BUSTING - the truth behind HVLS cooling
So….apparently there’s been a lot of talk out there in the air movement industry about how HVLS fans can lower ambient temperatures inside buildings (I’m looking squarely at you…Fans with a Posterior Larger than Normal). Is this really true? Can you simply place HVLS fans throughout your facility and have it act like air conditioning? Sadly, friend, the answer is no. Then….why do fan companies make these claims? Let’s dig a little deeper, shall we?
All of you smart readers out there know that fans do not cool air, they simply move it. So why do fans make us feel cooler? Well….one reason is because you’re hot and sweaty! Wait…what? It’s true! Let’s break it down. When a fan accelerates air, you feel that air move across your skin. And since its summer (or at least close to it), you’ve been sweating – a lot. So when this accelerated air meets your perspiring skin, the sweat evaporates. This evaporation carries heat away from your body, so even though there’s been no change in the air temperature around you, it FEELS cooler!
Even if you’re not moving around and sweating, HVLS fans can still make you feel cooler without an actual ambient temperature drop. This is due to the fact that we all have a heat “envelope” of 88 - 92°F air that encases our bodies. When air movement removes this “envelope” in a continuous fashion, relief can be felt despite the lack of perspiration. See there? A mystery solved and an advertising myth debunked all in two paragraphs!
Here’s something else the “other guys” won’t tell you. When the air temperature around you reaches 95°F or more, using fans to move air across your skin will actually make you feel hotter, not cooler. If this is routinely the case in your facility, you may want to think about other ways to reduce the overall temperature profile (evaporative roof cooling, anyone?).
Looking for more truths in air movement advertising? Check out Patterson’s complete lineup of fans, designed to make good use of all that body cooling sweat you’ll be producing this summer season!