Admittedly, their mettle might melt by the end of today, but many in the small and sweaty fraternity of suburbanites who willingly shun air conditioning take comfort in sticking to their guns in weather that has most people sticking only to vinyl chairs.
While the U.S. Energy Information Administration says 90 percent of Illinois households enjoy air conditioning, that percentage is lower at the environmentally conscious Prairie Crossing community in Grayslake.
"We camp out in the basement. The basement is really fun," Erin Cummisford, an employee of the Prairie Crossing Learning Farm, says of her family's approach to coping with the heat. "It's cool down there."
Cummisford, her husband, Rick, and their sons Ian, 11, and Brent, 9, have a full lineup of beds in the basement and look at hot weather as a chance for an adventure.
"It's a little bit of a challenge. How cool can we keep the house without using air conditioning?" she says, explaining how they take advantage of cooling methods such as pulling down window shades when the sun is out and opening the windows at night.
But, she is quick to point out, "you have to use common sense." Their home has a central air conditioning unit. If evening doesn't bring some relief from the heat, she says her family will break down, turn on the air and set the temperature at 78 degrees to ensure a comfortable night's sleep.
The family of Nathan and Mayumi Aaberg doesn't have that option. When they built their home in Prairie Crossing, the couple looked at statistics showing that air conditioners consume 5 percent of our electricity and add millions of tons of carbon dioxide to the atmosphere and chose to depend instead upon shade trees, insolated window shades and other energy conservation cooling methods.
"We can't keep doing what's normal if that's not a good thing for the earth," says Nathan Aaberg, who is associate director of Conserve Lake County, the environmental agency that used to be known as Liberty Prairie Conservancy.
Making the choice to forgo air conditioning removes the temptation to use it.
"If you have cookies around, you are more likely to eat cookies," he notes. Committed to "trying to live ethically," the couple won a 2007 contest for using the least amount of energy, Aaberg says.
Sons Alden, 14, and Owen, 10, and daughter Naya, 4, ride out hot spells by sleeping in the basement, the dad says. But he notes that he doesn't feel superior to people who will use air conditioning in this heat.
"I'm not trying to advance this idea that we're a happy blissful family when it's hot," Aaberg says. "My son (the teenager) accuses us of being Luddites. And to be honest, sometimes we are severely tempted to get air conditioning."
But for those who can get by without AC, there are perks beyond saving the earth and saving money, say Debra and Mike Hruby, who have lived in their Wheaton home without air conditioning for 32 years. During the killer heat wave of 1995, they stopped cooking in the kitchen and ate so many salads that Debra became a vegetarian. When they added on to their home, they ignored suggestions to include central air, but did build a rooftop (the Hrubys call it their Hruftop) deck where they eat meals in the shade on warm nights. She grew up without air conditioning.
"If it got really hot, you went to an evening movie," she remembers. "It was dark and it was cool. I remember when that was a neat part of summer."
She says today's scorcher might propel them to see "Moonrise Kingdom," that charming and quirky Wes Anderson film they've been wanting to see. Of course. they probably will have to bring sweaters for the air-conditioned theater.
Bewildered by those who lower the thermostat to 68 degrees in the summer and crank it to 78 in the winter, Hruby says, "It's far easier to be warm all the time than to go in and out of air."
Aaberg, who grew up in the Logan Park neighborhood of Chicago in a home without air conditioning, says he remembers scooching onto the part of his bed nearest the window and trying to catch a breeze while he listened to the sounds of the city at night.
"It's actually a good memory," Aaberg says. "At least, now it is."
And just as a snowstorm often brings out neighbors with shovels and builds a sense of community, heat spells can unite those without air conditioning.
"On a hot summer night, we'd sit outside until midnight," Aaberg says, recalling how people would get to know the neighbors and wile away the hours telling stories. "Now, everyone's inside watching TV in air-conditioned comfort and isolated from one another."
Unless, of course, this hot spell brings on power outages.