(Radio Iowa) – Temperatures have already been dipping below freezing in several Iowa cities, prompting some of us to bring our space heaters out of storage to warm up our homes at night. Lieutenant John Nelsen, of the Sioux City Fire Rescue, says it’s a bad idea to leave those devices on 24-7.

“We definitely don’t recommend you leaving on the space heater, especially when you’re sleeping,” Nelsen says. “We encourage you to shut them off when you leave a room if you’re the last one in the room. You never know if you have a pet in there that could knock a blanket or something closer to the space heater that could potentially cause it to start a fire.”

Nelsen says to never run your space heater near combustibles, like newspapers or magazines. He suggests keeping at least a three-foot ring of clearance around the devices. Also, Nelsen says you shouldn’t be surprised if your smoke detector goes off as you switch on your space heater or furnace for the first time.

“Especially in the winter time, we start using those space heaters that have been stored all year, start kicking on furnaces,” Nelsen says. “We’re going to have our smoke detectors start chirping just because from the dust that’s accumulated on those appliances.”

He says it’s also important to snuff out any candles you have burning before heading to bed, noting, a few recent fire calls in Sioux City were due to unattended candles.