An excessive heat warning is in effect for Phoenix through Thursday. Temperatures could get as high as 111 degrees.

While many adults hide in their air conditioned homes, it is not unusual to see children playing outside. Phoenix Children's Hospital Pediatric Resident Rosika Singh says that despite their apparent oblivion to the heat, kids are even more susceptible to weather-related illness than adults.

"Children, being children, don't always pay attention to the warning signs that we as adults pay attention to," Singh said. "They don't go back into the house and they don't drink enough water and they don't do the things that kind of prevent themselves from having heat stroke or becoming overly dehydrated."

Singh calls for increased vigilance from caretakers. She says when kids play outside, it is important for them to drink water often, play in the shade and avoid caffeine.

Despite children's desire to play outside, Singh said it is also important to have them take frequent breaks where they come inside and rest.

While many rely on air conditioning for these kinds of breaks, increased temperature can also wreak havoc on home and car air conditioners. 

Mickey Hermes, owner of The Auto Shop in Phoenix, said by 11 a.m. he had already seen four cars come in with air conditioning problems.

"Business tends to pick up on the summer months when the heat comes," Hermes said. "Car systems fail and have trouble and it means there's more cars in the shop for us."

Right now, Hermes says there is about a four-day wait to schedule an appointment for air conditioning repair.

Bill Worlock, owner of Worlock Air conditioning, said he has seen an increase in new equipment sales and a lot more service calls. So much so, that even as the owner he is out in the heat fixing air conditioners. 

"We have increased call volume so as a business owner I am out assisting our service technicians as well as our install team," said Worlock. 

Worlock said that the highest number of service calls come in during the hottest part of the day, from 3 to 8 p.m., when people are coming home from school and work. So he and his technicians need to arm themselves against the heat. 

"It is actually very hot out there, so you have to prepare yourself," Worlock said. "You have to drink a lot of water, Gatorade and do it every 20 minutes. To be able to withstand the high temperatures you have to hydrate yourself."  

Worlock does what he can to protect his workers from the heat. 

"We usually start at 5 a.m. to avoid the extreme heat on the installation, and on the service side we try to minimize our time in the field," said Worlock. 

Although the record heat can be hard on everyone, for those in the air conditioning business it can also be an economic boon.