You can feel it when you step outside or grab your seatbelt buckle — triple-digit temperatures are back in Phoenix.

Summer in the Valley consists of closed blinds, air conditioners on full blast and pools that feel like bath water. You'd better hope your air conditioning unit doesn't need maintenance , because 2025 is shaping up to be hotter than average .

More than nine in 10 Arizona homes rely on air conditioning , consuming more electricity than the residential sectors in three-fourths of the United States, and more per capita than seven-tenths of the states.

It's essential, but do we even know how the air conditioner came to be? Here's all of the air conditioning lore you've ever wanted to learn.

How Indigenous peoples stayed cool

According to The Square PHX 's education department (the historic neighborhood formerly known as Heritage Square in downtown Phoenix), Indigenous peoples built homes using the caliche-rich soil found in central Arizona.

Caliche is a mineral deposit of gravel, sand and nitrates, found in especially dry areas. While caliche makes digging difficult, it helps to hold adobe bricks together, which was beneficial for these early Arizonans.

The clay bricks used in the late 19th century were not as efficient at keeping homes cool, so the houses were built with high ceilings to pull hot air up. Many families would sleep outside on "sleeping porches" during the intense summers.

When Phoenix was resettled during the 1860s, many people used adobe to build their homes. The adobe blocks were made by mixing dirt, water and straw, then drying out in the sun. Not only is adobe cheaper than brick, its high thermal mass also helps homes stay cool.

The invention of air conditioning

In the 1840s, a Florida investor named John Gorrie believed cooling cities would help avoid diseases like malaria .

His first cooling systems required the transportation of ice from frozen lakes into Florida (a notoriously humid state). When Gorrie realized his methods weren't efficient, he began experimenting with artificial cooling, which laid the foundation for modern air conditioning.

Nearly half a century later an engineer named Willis Carrier was presented with a humidity problem at a Brooklyn publishing company. The damp conditions were causing magazine pages to wrinkle.

Carrier designed a system based on cooling coils that controlled humidity by heating or cooling water. He patented his system, calling it "Apparatus for Treating Air."

The system would evolve into smaller and more affordable devices that could be installed at home. When most newly built homes had central air conditioning, the population grew in hot states like Arizona.

Memories of a time before air conditioning in Arizona

Marshall Trimble is an author, singer, educator and Arizona's official state historian. He was born in Tempe in 1939, long before homes came equipped with any form of air conditioning. "I'm ancient," he said jokingly.

Trimble grew up in wartime America. He spent much of his early summers in the East Valley, cooling off in irrigation ditches and canals. He remembered pretending the caterpillars that swam by were Japanese ships.

Just as the snowbirds come and go at the perfect times each year, people have always vacated metro Phoenix during the blazing summers. The only difference then was the lack of social activities or sports events to attend.

"Phoenix died during that time," Trimble said, explaining that kids spent all day playing outside because it was their only choice.

Families who could afford it would escape the dry heat in San Diego, Trimble said. He didn't have much money growing up — his family worked on farms and railroads. Those who couldn't travel far, like Trimble's family, would take the train up to the Bradshaw Mountains and cool off in Prescott.

It was hot, but the 100-degree days were not nearly as common in the mid-20th century as they are today. Trimble also spent time living in Ash Fork while his dad worked for the Santa Fe railroad. While it wasn't San Diego, it was significantly cooler than the Valley. He said he misses those years.

Similar to how Indigenous peoples utilized sleeping porches, Trimble recalled sleeping outside on the farm, only heading back inside when the monsoon storms came each August.

Trimble remembered the monsoon being much more reliable back then, compared with the unpredictable and far less frequent storms of today. They counted on the rain to provide "some sort of respite from the insufferable heat," he said.

He also recalled early attempts at cooling systems that looked like Rube Goldberg-style contraptions attached to windows. Using chicken wire and an electric fan, one end blew air inside the home, while a garden hose outside dripped water onto charcoal, Trimble said, laughing at how unsafe it was.

How we went from swamp coolers to central AC

Trimble referred to 1950 as the dividing line between historic and modern Arizona.

After World War II, a carpenter named John F. Long built the first master plan community in the state of Arizona: Maryvale. The neighborhood was complete with parks, schools and swamp coolers on roofs for cooling.

Swamp coolers were the first widely adopted form of air conditioning in the state. These units cool air by evaporating water, which increases humidity.

However, this method doesn't work very well when the dew point rises. Trimble said swamp coolers were "almost useless" during the August monsoon seasons. It wasn't until a construction boom in the 1970s and 80s that more homes began having air conditioning units in place of swamp coolers.

The 2 most common types of home AC

The two different types of air conditioning units we see most in Arizona are package units and split systems. Package units are the bulky air conditioners that sit on roofs, while split systems have one unit outside of the home, usually on the ground, and another unit inside. Does this sound familiar?

While these split systems are more efficient, they're common mostly on homes built within the past 30 years, Joe Granado, associate professor at Arizona State University, told Valley 101. The switch was made to accommodate city regulations and aesthetic preferences.

For older houses, updating a package to a split system would be a lengthy, costly process. "The replacement market basically just replaces that product," Granado said.

Not only would the electricity and ductwork need to be modified, but upgrading to a split system would cost close to $25,000. For many Arizona residents, replacing a broken package unit every so often for a few thousand dollars is the more feasible option.

However, after our look back into pre-air conditioning Arizona, maybe having a guaranteed way to cool our homes is worth the higher costs and complex machinery. We've sure come a long way.

Trimble called Phoenix the "air conditioning capital of the world." It came as no surprise to learn that the Valley of the Sun was a pioneer for evaporative coolers and modern air conditioning.

Arizona Republic producer Amanda Luberto and reporter Laura Daniella Sepulveda contributed to this article.