Residents at Mount Carmel Gardens on the Southside, many of whom are senior citizens, are living without working air conditioning and have been for nearly a month.
Management at the complex off University Boulevard says it will be four to six weeks before it's fixed.
Jacksonville has seen extreme heat recently, with feels-like temperatures reaching triple digits.
"Smell; it's musty. I can't sleep, can't even use my oxygen machine half the time because it puts out so much heat," said Paul, a four-year resident of the high-rise.
Paul is one of hundreds dealing with the heat not only outside, but inside his own home at the complex. Residents say it's unbearable.
"That's a health hazard. The temps have been in the double-digits with the heat index," resident Kenny Dockswell said. "One of my neighbors yesterday had to get taken to the hospital because of the heat, and everybody's got fans. You can't live like this."
A manager with the complex read Channel 4 a statement Thursday morning but wouldn't answer any questions. She said the AC was functioning at 50 percent when a lighting strike created further damage last month.
Management said the system is a bigger size than one that can be bought from a local hardware store, so it will take four to six weeks to fix the system.
"Areas of the building are below 70 degrees, and they're recommended to keep the thermostat at 78 so they're doing OK," property manager Charee Russel said.
Residents said they're not doing OK, but Russel said they're doing what they can to keep everyone happy.
"We have installed portable ACs, fans in the community room and in the vacant office so the residents can come down and get cooled off if they need to if they feel they're too hot," Russel said.
Even though it will likely take more than a month to get their residents back to being comfortable, management says residents are their No. 1 priority.