Medium heat on an iron falls between 230°F and 300°F (110°C to 150°C), which corresponds to setting 2 or 3 on most iron dials. If your iron uses the international dot system instead of numbers, medium heat is the two-dot setting. This range is designed for fabrics that need real wrinkle removal but can’t handle the high temperatures used for cotton or linen.
How to Identify Medium Heat on Your Iron
Iron controls vary by brand, but they all communicate the same basic scale. Some irons use a numbered dial from 1 to 5 or 1 to 6, where medium heat sits around 2 or 3. Others label settings by fabric name, listing options like “silk,” “wool,” or “polyester,” all of which fall within the medium range. Many newer irons display the international dot system: one dot for low, two dots for medium, three dots for high.
You’ll find the same dot symbols on clothing care labels. A small iron icon with two dots printed inside means the garment is safe to iron at medium heat. Matching the dots on your label to the dots on your iron is the simplest way to get the temperature right without memorizing numbers.
Which Fabrics Need Medium Heat
Medium heat works for fabrics that wrinkle noticeably but are too sensitive for the high temperatures cotton and linen require. The main ones are:
- Wool: Responds well to medium heat with light steam. Too high a setting causes discoloration or scorch marks.
- Silk: Wrinkles easily but scorches fast, making medium the ceiling for safe ironing.
- Polyester: Synthetic fibers can melt at high heat, so medium is the safe zone.
- Satin: Often made from polyester or silk, both of which need this temperature range.
- Acrylic: Another synthetic that distorts or melts under too much heat.
- Lace: Delicate structure that can warp or burn at higher settings.
Natural fiber blends, like cotton-polyester, also do well at medium heat. The synthetic component in the blend sets the upper limit for temperature, so you iron to protect the more sensitive fiber rather than the tougher one.
Using Steam at Medium Heat
Most irons generate enough steam at medium heat to be useful, though you won’t get the full blast you’d see at the cotton setting. For blends like cotton-polyester, moderate steam pressure combined with medium heat gives you effective wrinkle removal without risking the synthetic fibers. Keep the iron moving in gentle, overlapping strokes to prevent water spots and distribute heat evenly.
For wool specifically, a light mist of water sprayed on the garment before ironing works just as well as the steam function. The Woolmark Company recommends either approach: spray the garment first or use your iron’s steam setting while pressing. The added moisture relaxes the fibers and makes creases release more easily.
Techniques That Protect Your Fabric
Getting the temperature right is only half the job. How you handle the iron matters just as much at the medium setting, especially with wool and silk.
With wool, lay the garment flat and reshape it gently by hand before you start. Use light pressure as you iron. Pressing down hard flattens the natural texture of the fibers and creates a shiny, worn-looking surface that’s difficult to reverse. If you’re working with a wool sweater or blazer, ironing on the reverse side adds another layer of protection against shine.
Silk and satin benefit from a pressing cloth, which is just a thin piece of clean cotton fabric (a pillowcase works) placed between the iron and the garment. This buffer prevents direct contact with the hot soleplate, reducing the risk of scorching or leaving iron marks on the surface. Iron silk while it’s still slightly damp from washing, or use a spray bottle, since dry silk is more prone to water spotting from steam.
For synthetics like polyester and acrylic, iron on the reverse side whenever possible. These fabrics can develop a slight glaze on the surface from direct heat, and flipping them inside out prevents that without requiring a pressing cloth.
What Happens if You Use the Wrong Setting
Setting your iron too high for medium-heat fabrics causes damage that’s often permanent. Polyester and acrylic can partially melt, leaving stiff, shiny patches or even sticking to the soleplate. Wool scorches and discolors, turning brown or yellow in spots. Silk develops a brittle texture and visible shine where the heat was applied.
Going too low is less risky but frustrating. You’ll press over the same wrinkle repeatedly without results, and the extra passes can stretch delicate fabrics. If medium heat isn’t smoothing out your wrinkles, the issue is more likely moisture than temperature. Add a bit of steam or spray water on the fabric rather than turning up the dial.