Look at any urban street under the blazing hot July sun, and you’ll think of high daytime temperatures and unbearable heat.  It’s a vicious circle.  As summer approaches and temperatures rise, we crank up the AC to stay cool indoors.  Our air conditioner pumps out heat exhaust, which adds to the urban heat island effect in our cities.  But at least things cool down at night – right?

Maybe not… A recent study by a team of researchers at Arizona State University (ASU) tells us that – as things heat up in the city during the day, the air conditioners we run at night are still adding to the overall urban heat island effect.  They also found that nighttime exhaust has a greater effect on overall temperatures.

From ASU’s press release:

They found that the effect of the AC systems was more important during the night due to the limited depth of the urban boundary layer.  The effect is stronger from late afternoon to early morning.  A smaller quantity of excess AC systems heat ejected during the night can increase the air temperature more compared to a greater quantity released during the daytime when the hot sun is beating down.

You can find the full report HERE.