They keep us cool, but they're hot with thieves.
Over the past weekend, dozens of commercial air conditioners have disappeared in Radnor Township, Marple Township, and Yeadon.
The price of copper has hit a 20 year high.
Cooling units have yards of copper tubing inside.
At the current rate, they're worth $400 to $500 at scrap yards.
Four units were stolen at the Eagle Village shops in Wayne.
It's hot in the kitchen at A Taste of Britain, but, on Saturday, it got even too hot for the chef.
"So, I walked outside and, no doubt, all the cords are cut and everything's gone," chef Michael Taylor said.
The thieves don't even have to worry about being electrocuted when they snip the wires. The switch boxes are typically right next to the unit. They're unlocked, so, they just turn it off, clip the wires and they're out.
"Usually there're two or three perpetrators involved because the units are rather heavy, 200 to 300 pounds. They'll cut them and they'll boost them onto some kind of skid loader or truck and leave the area rather quickly," Radnor Police Sgt. Andrew Block said.
They tried to take six units behind an office building in Wayne, but apparently, as they are still at the building, something spooked the thieves and they left without them.
10 were taken from an office complex in Marple.
Several of the stolen units at Eagle Village have been replaced.
They typically cost $3,000 to $5,000 - a huge expense for small businesses.
Radnor and Marple Township police believe the thefts are all connected.
The police are hoping someone noticed suspicious activity or a vehicle and might be able to help them track down the thieves.