Adding a portable space heater to your cold-weather arsenal could make these bitter winter days a lot more bearable. These heaters used to get a bad rap because of safety concerns, but like many home appliances, today’s models are designed to be safer and sleeker than the heaters of old.

When used carefully, they allow you to provide supplemental heat in a small, targeted area as opposed to dialing up the thermostat for your entire house.

“It’s something you may remember when growing up in your grandma’s house, but they used to be a lot more dangerous than they currently are,” says Brett Brenner, president of the Electrical Safety Foundation International (ESFI). They still require mindful operation and, he says, “people do leave them on overnight when they are sleeping, and we still don’t recommend it.”

In the past 10 years, manufacturers have improved built-in safety features such as a tip-over shut-off switch, says Jill Notini, a vice president at the Association of Home Appliance Manufacturers (AHAM).

There are several types of units on the market, so it’s important to research which is best for your needs and the size of your space. When buying a space heater, look for a safety certification from an organization such as Underwriters Laboratories (UL) or Intertek’s ETL Mark.

Never buy a used heater, Notini says: “You don’t know the history of the product or what condition it was stored in or whether it was ever dropped.”

Here are five tips on using portable electric heaters from AHAM and ESFI. As always with new appliances, the first thing you should do is read all the directions and warnings provided in your instruction booklet.

1. Don’t leave your heater on in an unattended room. “Never keep your portable electric heater on when you are sleeping; it’s not worth it,” Notini says.

2. Keep a three-foot perimeter around the unit clear. Never store clothing on or around the unit, or put it too near curtains or beds. Never cover the cord or put anything on top of it. Do not use it as a towel warmer or clothes rack.

3. Be mindful of where you plug it in. Plug space heaters directly into an outlet. Never use an extension cord or a power strip, which could overheat. And don’t plug anything else into the same electrical outlet as your heater.

4. Beware of kids and pets. Either could knock over a space heater, so be extra careful to watch toddlers or cats and dogs around your heater. Unplug it when not in use.

5. Inspect it regularly. Because you use space heaters for only a few months during the year, take a good look at your unit when you take it out for the season. Make sure that your cord isn’t damaged and doesn’t feel hot to the touch when in operation.