Why homes often feel warmer than the thermostat suggests – and what to do about it
(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)
Jonathan Bean, University of Arizona
(THE CONVERSATION) Picture two homes on the same street: one constructed in the 1950s and the other in the 1990s. There are no trees or other shade. The air conditioning units are identical, recently replaced, and operating perfectly. Identical thermostats are set at 82 degrees Fahrenheit (27.8 Celsius).
When it’s 110 F (43.3 C) outside, the 1950s house will likely feel at least 10 F (5.6 C) warmer inside, even with the same air temperature.
Why?
The answer has to do with radiant heat. Radiant heat is what keeps you toasty warm at a campfire on a cold winter night. The fire doesn’t warm the air much; rather, like the Sun, most of the fire’s heat moves through invisible waves directly from the campfire to your body.
In the radiant heat of the Arizona sun, the surface temperature of the uninsulated post-and-beam ceilings in my house, one of 41,000 built in Tucson during the post-World War II era, can reach over 100 F (37.8 C). The single-glazed steel windows register 122 F (50 C), and the uninsulated concrete block walls aren’t much cooler.
Inside my house on triple-digit days, it can feel like I’m standing near a campfire, even with the air conditioner roaring to maintain 75 F (23.9 C). And when the system breaks – as it did...