In summer, no matter where you live, you sometimes wish for a cooler house. "Sultry" is the word they taught us in school for those days of heat and humidity that sap your energy and make you feel clammy and damp. The woman in the photo is using an ancient strategy, moving air across her skin to promote the evaporation of moisture, which removes heat from her body and dries her skin to a more comfortable level. Fans are always good.
But what happens on those days when fans don't work? When the humidity is so near "dew point" that no evaporation is possible? When the air contains so much moisture at its current temperature that it can't receive any more? You can drive to the beach or lake or pool and immerse yourself in water to cool down, or.....
Enter air conditioning, a technology older than you might think, which cools the air in a space and, at its best, lowers the moisture content of the air so that evaporation can remove heat from people and animals therein. Simply blowing air across quantities of ice is an ancient application. Willis Carrier devised a refrigerating device that cooled air using ammonia as a compressible refrigerant in 1902. We now use non-toxic gases in home and auto air conditioners, but the environmental impact of those gases has us looking for the next generation of refrigerants that don't pollute nearly as much. More on that another time.
Here, as I say often, is the secret: any air conditioner that can cool room air to a temperature below its dew point in one pass across its coils will eventually render a space comfortable for people and animals. Moisture drops out of the cooled air, drains off somewhere in a responsible way, and the air now feels more comfortable, breathable, drier, and the moisture evaporating from your skin is removing just over 1000 btu per pound of sweat. Don't think too graphically about the idea of a pound of sweat, but athletes in extremis can shed ten pounds or more from perspiration and evaporation during a game or training session, and marathon runners dread humid days for races because they will sweat just as much but not be able to control their bodies' temperature as well in those conditions. Just like you, in a milder way, on a hot day, entering a room full of cool, dry air. Wonderful. Or unable to find a cool space and wiping away pints (pounds) of perspiration and still feeling hot and miserable.
Today in my zip code it's only 77 degrees Fahrenheit, but it's 95% relative humidity. That means the air is burdened with 95% of the water it can contain at that temperature, and it's unlikely to accept that last 5% without more wind than we have. It's uncomfortable, sticky, still and not going to improve until thunderstorms come later in the day to reduce the humidity. Good day to use air conditioning to dry out the air inside, even though the temperature is not oppressive.
Even if you air condition only one special room in your house (bedroom, tv room, basement den) as a refuge on miserable days, you can give yourself a place to get comfy and avoid the toll of heat stress (the link is a bit lurid, beware). Or you can take a shower to cool down, hug the fan like the young woman in the photo, drink lots of iced stuff, and gripe about the weather to anyone who will listen. It seems to help, somehow.
But what happens on those days when fans don't work? When the humidity is so near "dew point" that no evaporation is possible? When the air contains so much moisture at its current temperature that it can't receive any more? You can drive to the beach or lake or pool and immerse yourself in water to cool down, or.....
Enter air conditioning, a technology older than you might think, which cools the air in a space and, at its best, lowers the moisture content of the air so that evaporation can remove heat from people and animals therein. Simply blowing air across quantities of ice is an ancient application. Willis Carrier devised a refrigerating device that cooled air using ammonia as a compressible refrigerant in 1902. We now use non-toxic gases in home and auto air conditioners, but the environmental impact of those gases has us looking for the next generation of refrigerants that don't pollute nearly as much. More on that another time.
Here, as I say often, is the secret: any air conditioner that can cool room air to a temperature below its dew point in one pass across its coils will eventually render a space comfortable for people and animals. Moisture drops out of the cooled air, drains off somewhere in a responsible way, and the air now feels more comfortable, breathable, drier, and the moisture evaporating from your skin is removing just over 1000 btu per pound of sweat. Don't think too graphically about the idea of a pound of sweat, but athletes in extremis can shed ten pounds or more from perspiration and evaporation during a game or training session, and marathon runners dread humid days for races because they will sweat just as much but not be able to control their bodies' temperature as well in those conditions. Just like you, in a milder way, on a hot day, entering a room full of cool, dry air. Wonderful. Or unable to find a cool space and wiping away pints (pounds) of perspiration and still feeling hot and miserable.
Today in my zip code it's only 77 degrees Fahrenheit, but it's 95% relative humidity. That means the air is burdened with 95% of the water it can contain at that temperature, and it's unlikely to accept that last 5% without more wind than we have. It's uncomfortable, sticky, still and not going to improve until thunderstorms come later in the day to reduce the humidity. Good day to use air conditioning to dry out the air inside, even though the temperature is not oppressive.
Even if you air condition only one special room in your house (bedroom, tv room, basement den) as a refuge on miserable days, you can give yourself a place to get comfy and avoid the toll of heat stress (the link is a bit lurid, beware). Or you can take a shower to cool down, hug the fan like the young woman in the photo, drink lots of iced stuff, and gripe about the weather to anyone who will listen. It seems to help, somehow.
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Any air conditioner that can cool room air to a temperature below its dew point in one pass across its coils will eventually render a space comfortable for people and animals. Moisture drops out of the cooled air, drains off somewhere in a responsible way, and the air now feels more comfortable.
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