Sometimes, the only way to tell you’ve been robbed is if the day starts to warm up and your building fails to cool down.

That was the case last week at Interior Ideas/Wildflower Café. At the height of Bluebonnet Trails season, manager Suzanne Rhoten was frustrated to learn the A/C unit had been stripped by thieves when the air conditioner repairman came in and said she needed to see what had been done to the unit.

Neighboring units hadn’t been touched; a repair bill in the thousands has the business looking for ways to safeguard against further thefts, she said.

“We’re going to need to do something,” she said.

Detective Sgt. Mike Hopson of the Ennis Police Department said theft of air conditioner condenser coils is getting more popular among the criminal set.

“With the cost of copper and aluminum right now, it’s becoming more of a real problem,” he said.

So what can businesses and residences do to protect their property?

Locked fences and even cages and security lights that come on when they sense movement can help, he said, recommending that people keep their eyes open.

“Keep your eye on your stuff. Be aware of suspicious people. If the guy’s not in a uniform or driving a truck marked with A/C repair, please contact us,” he said.

Once considered an urban problem, copper theft has spread to outlying areas.

Often in the theft of materials, the tragedy is that swiping a few bucks worth of copper coil from an air conditioner can cause costly damage for a small business that can ill afford it.

“You may get $75 for the coils and aluminum and copper, when it costs $3,000 to replace the unit,” Hopson said.

Homes under construction are particularly vulnerable – after plumbing is roughed in, copper thieves like to move in, pulling copper pipes right out of the ground. They’re getting more resourceful, striking existing businesses as well.

“At the Red Moon, they pulled the copper wire out of the ground, from the pole to the building – they cut it at both ends and pulled it out of the conduit,” Hopson said.

He doesn’t believe the thefts are part of an organized ring – just a lot of small-time criminals figuring out a new source of illicit revenue.

“There are so many copper thieves out there right now, it’s crazy,” he said.

The copper thieves are no respecter of persons, Hopson said, noting that First United Methodist had a theft this week.

There’s another, more dangerous downside to the thefts.

“They’re releasing the Freon from the units when they cut the copper – I’m assuming that’s still hazardous material and it’s not good for the environment,” he said.

When thieves stole an A/C unit from the former Carver school site, they were putting themselves at risk, he said.

“When we got there to photograph the evidence, the switch was still on – they cut the wires, and the switch was still on. That’s definitely dangerous,” Hopson said.

At Maverick Metal Trading, owner Brad Lane has Hopson on speed dial.

With the price of copper and other metals soaring, construction sites and commercial air conditioners are prime targets for thieves. But local metal merchants aren’t about to become partners in crime, Lane said.

“If someone comes in with a commercial quantity and they’re not a commercial entity, we do not accept those,” he said. “The state is doing its part and we’re doing our part.”

Department of Public Safety regulations in effect as of September 2007 and April 2008 require him to get driver license and license plate information on the sale of second-hand materials.

“We provide those records to the DPS and any police enforcement agency,” Lane said.

Occasionally, the risk works the other way, Lane said, citing a man who stole an aluminum hatch cover from the Ennis water treatment plant. He took the cover to a local recycler, got arrested, charged with a misdemeanor and bailed out.

“He’s out on bail, goes back and steals the same thing again. We bought it for $18,” Lane recalled.

The man was arrested once more. Only this time, because he was messing with a water treatment plant for a municipality, he faced felony charges.

“It’s an $18 felony, because that’s considered terroristic,” Lane said.

Local metal dealers work together to prevent crime, he said. “We all call each other,” he said.

E-mail J. Louise at jlouise@wninews.com