Weather is an important consideration in many energy conservation projects, both in the amount of energy used (e.g. to extract humidity from the air inside a building) and in the final product: comfortable air in the occupied zone. Ideal humidity levels are fairly evident in the summer. Not even my cats, Bevo and Oscar, like to lounge outside on a hot and humid afternoon, even when the sun’s out in all its glory.
Having lived along the Gulf Coast most of my life, I always assumed the summer humidity was better up north. Not so! It gets miserable even in Des Moines, Iowa (scroll down to look at the “Humidity Comfort Levels” section) ~ and throughout the middle of the continent (west of the Mississippi). Why? Because when it’s hot, the body perspires and tries to cool off your core temperature via evaporative cooling. When it’s humid outside, it’s harder for sweat to evaporate from your skin, so you suffer the consequences.
What about in the wintertime? All the anecdotal references say you feel colder in the winter when it’s more humid outside; that you can be quite comfortable – shirt sleeves! – on a very cold day if it’s also really low humidity outside. That’s been my experience, too. (We’re not talking about the wind chill factor here, just ambient temperature on a calm day.)
But, is wet cold really more uncomfortable than dry cold? Finally an answer to this perennial dilemma.
I have very, severe, extreme dry eye. Five years ago when my eyes got so bad, I resolved to move to the ideal location: lots of humidity, not too hot in the summer, not too cold in the winter ~ and NOT along the Gulf Coast. I ended up in Western North Carolina, at 2000 feet altitude in the Appalachian Mountains. One of the rainiest areas in the U.S. outside of the pacific northwest.
Well, for all my learning and all my research, I never realized that the humidity data on all the weather charts I studied meant – Doh!! ~ clouds. Lots and lots of clouds, all year long ~ worse even than the Pacific northwest. (Lots of thunderstorms, too; more than even in south Louisiana or central Mississippi! Fortunately, I love stormy weather.)
How could I have been a 93E Weather Observer in the US Army and not realized that high humidity = lots of clouds. In the weather this means the same thing: when it’s real humid outside, it’s typically also very cloudy ~ ergo no sunshine. And so, it’s the absence of sunshine that makes humid weather feel so much colder.
Sunshine has the same effect in summer – it feels 10 F warmer in sunlight than in shade; likewise in winter. It’s just that in the winter, when the sun is out it’s always less humid.
One more mystery solved.
__________
Excerpted from Going Green, available as an eBook at this list of eBook retailers online.