Firemen in Florida are having a hard time standing the heat — but not while they're battling the flames.

Charlotte County firefighters are saying that the firehouses are too hot — or too cold — because the county has put lockboxes over the air-conditioning control units at the stations, the Charlotte Sun reports.

The Charlotte County firefighters' union claims that the boxes have violated the terms and conditions of employment in the current bargaining agreement.

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The county has been trying to conserve energy and reduce its $6 million-per-year electricity costs, the newspaper reported.

About a month ago, lockboxes were installed to keep the temperatures at the stations at a constant 72 degrees Fahrenheit, which is the lowest temperature on a nationally recognized comfort scale, according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

Union representative Scott Heinis told the newspaper that it's impossible for him or anyone to tell what temperature it is because of the boxes covering the air-conditioning control units. He also said that each station has a temperature gauge in only one room, so temperatures throughout the station can vary 5 to 8 degrees.

The newspaper reported that the lockboxes were proposed by county staff and approved and agreed to by Fire Chief Dennis DiDio.

The county argued that the firefighters have made a habit of leaving windows and doors open, bringing the heat from outside into the stations and wasting energy and money on the air-conditioning.

Heinis, however, told the newspaper that doors and windows have to be opened because some of the stations are so cold inside. He told the newspaper that each lieutenant should have control of the temperature for that station.

"Our lieutenants and our officers are very highly paid professionals," Heinis told the newspaper. "They should be given the leeway to make decisions based on the standards that the county sets."

The formal complaint comes as the union and county are in the midst of negotiations for a new collective bargaining agreement. The current contract between the workers and county expires at the end of September.

Heinis told the newspaper that he and the union reluctantly filed the grievance, but he feels they were forced to due to a lack of cooperation from DiDio and the county.

"I've been stymied at every turn," Heinis told the newspaper. "Believe you me, the union does not take filing a grievance lightly."

The Associated Press contributed to this report.