Flat iron Buying Guide

Getting started

When you want to iron out those curls and kinks and a blow dryer isn't enough, straightening irons can get the job done--if you pick the right one. Our tests turned up a few winners that will keep your tresses on the straight and narrow, no matter what kind of bed head you wake up with. We tested flat irons in our humidity chamber (to keep moisture and temperature steady) on swatches of naturally curly human hair, and testers counted how many passes it took to straighten them. To see how the flat irons perform on hair that's still attached to someone's head, we also asked nine staff members to try them at home.

As with blow dryers, wattage wasn't any indicator of performance; neither were high temperature settings. Claims of ionic, tourmaline, and nano silver technology didn't seem to make a difference in straightening performance either. (Something else to consider: Our experts say nano silver in consumer products has raised concerns about long-term safety.)

Our testers found that paying a higher price doesn't necessarily mean that you'll get a better flat iron. And you can't count on brand names to guide you to the best, either. Conair was the maker of the top- and bottom-rated models in our test. Another Conair model, the (no nano) Infiniti CS31, was great at straightening, but it pulled several testers' hair. Ouch! The straightener from CHI, a top-rated blow-dryer brand, was a disappointment in our tests. At $130, the CHI Ceramic GF-1001 was the second-most-expensive flat iron we tested, but it didn't rate anywhere near the top. And several panelists had complaints. One said that it felt as though it had burned her hair. Another told us that it "took a long time to get hot, and then it was too hot."

Get the most out of flat irons

Prep the hair

"Coat hair with a protective thermal styling product first," Mario Russo, a Boston salon owner whose clients include Teri Hatcher and Natalie Portman, said. "But never use a flat iron on wet hair. That will really fry the strands." Also, if hair is thick and wavy or curly, using a straightening lotion or mousse will make the process easier. Before straightening, use your fingers or a brush to detangle so that hair hangs down smoothly.

Clip it up

If hair is thick or unruly, twist it into four or five sections and clip each in place, leaving one section loose. Heat the iron, then use your fingers to lift and hold a small section of hair at a 90-degree angle from your head. "Clamp the iron down on the hair, close to the roots without touching the scalp, then pull it slowly down the length of the section all the way to the ends," Russo said. "Speed varies by hair texture, but about 1 second per inch of hair is a rule of thumb."

Fight the frizz

Wash your hair the night before and let it air-dry. "Hair is much stronger when it's naturally dried,"" said Ken Paves, Jessica Simpson's hairdresser. "If you dry hair with a blow dryer just before using a flat iron, the heat nudges the cuticles open, which prevents hair from looking shiny and can make it more prone to damage." For little frizzies along the hairline, Russo recommends brushing them flat with an old toothbrush coated with hair spray.

Don't get burned!

Straightening irons get hot fast--up to nearly 400 degrees in a couple of minutes. That's hot enough to roast a chicken--and burn skin on contact. Based on Consumer Product Safety Commission data, we estimate that hair straighteners account for hundreds of serious burns each year. That's not surprising, especially because they don't cool off immediately when you turn them off--cool-down periods ranged from 17 to 29 minutes in our tests. And the automatic shutoff on many models doesn't kick in for an hour. Children and the elderly are especially vulnerable to burns. Also, be aware that unlike blow dryers, flat irons aren't required to have safety plugs--they prevent you from being electrocuted if the iron falls into water--and we found that most don't have them. So you might want to find somewhere other than near a sink or tub to use a flat iron.