PORTLAND, Ore. — Overnight temperatures are set to plummet in Puget Sound this week, so many homeowners will take out their space heaters to stay warm.

We wanted to Verify: What's the safest way to use a space heater?

Several viral Facebook posts since last winter claim plugging a space heater into a power strip or extension cord can spark a fire, separate from the space heater itself.

Lt. Rich Chatman with Portland Fire said you should never plug your space heater into an extension cord or power strip. High-voltage appliances like space heaters can overheat power strips, sparking a fire.

Chatman said you can use a surge protector with an on and off switch.

"The surge protectors themselves – the kind with the on and off switch and light – that actually has a fuse in it, so when it starts to heat up, the fuse itself will melt and you'll lose the connection. So you'll essentially lose power," Chatman explained.

But your best course of action is plugging the space heater straight into a wall outlet.

"One of the common mistakes people make with these space heaters is plugging them into anything that’s not a wall outlet. Ultimately, that’s the safest way to use a space heater," Chatman said.

According to the National Fire Protection Association, space heaters are the second leading cause of US house fires and the third leading cause of home fire deaths.

And here are a few more tips to stay safe this winter while using your space heater:

  • Put your space heater on a flat surface -- not a carpet or furniture
  • Keep it at least 3 feet away from anything that could burn, like paper or clothing
  • Always unplug your space heater when you're not home