Flannel Sheets Guide: Weight, Fabric and How to Keep Them Soft

Flannel sheets are cotton or synthetic fabric brushed to raise a soft nap that traps warm air. Shop by weight, not thread count: makers such as L.L.Bean and The Company Store sell 5 oz. flannel, meaning five ounces per square yard. Keep them soft by washing gently and tumble drying on low.

What are flannel sheets made of?

Flannel started as a wool cloth. Today it is made from wool, cotton or synthetic fiber, according to Wikipedia’s summary of the fabric. Most flannel bed sheets are cotton, sometimes labeled flannelette, which is a napped cotton made to imitate the feel of wool flannel.

The Company Store explains the appeal simply: the fabric is woven and brushed, and the raised fibers “trap warm air.” That brushed surface is what makes flannel feel warm the moment you get into bed, unlike cool, crisp percale.

Synthetic flannel is usually sold as microfiber or polyester flannel. Check the fiber content line on any listing so you know which one you are buying, and follow that item’s own care label.

How is flannel made soft?

The softness comes from a finishing step called napping or brushing. The Encyclopedia of Clothing and Fashion describes it as feeding cloth through rollers covered in small, brushlike wires that pull loose fiber ends out of the yarn.

Brushing can be done on one or both sides of the fabric. Listings often call two-sided brushing “double brushed.”

The same entry lists the tradeoff. Napped fabrics “may also have increased pilling, abrade more easily even with care, or flatten with wear.” That is why care matters more for flannel than for plain cotton sheets.

What does flannel weight mean?

Flannel is not sold by thread count. Superior, a bedding maker, puts it plainly: quality “is measured in ounces per square yard (oz/yd²) rather than thread count.” Some sellers use grams per square meter (GSM) instead.

The GSM column is a straight unit conversion (1 oz per square yard is about 33.9 g per square meter), not a maker’s figure. The Company Store names three things to judge flannel by: material quality, weight and finish.

What should you check before buying flannel sheets?

Five details on a listing tell you most of what you need.

1. Fiber content. “100% cotton” or “100% brushed cotton” is the classic choice. Blends and polyester flannel behave differently in the wash.
2. Weight. If the listing gives ounces or GSM, compare against the table above. If it gives only thread count, treat that as a gap in the information.
3. Pocket depth. Measure your mattress, including any topper. L.L.Bean lists a 15 inch pocket depth on its Ultrasoft Comfort sets, which gives a useful benchmark.
4. Certification. An OEKO-TEX STANDARD 100 label means the item “passed safety tests for the presence of harmful substances,” with every component tested. The Company Store publishes the certificate number for its Velvet Flannel sheets. The label is about chemicals, not warmth or durability.
5. Where it was woven. Both maker examples above are woven in Portugal. Origin alone does not prove quality, but specific claims usually signal a more detailed listing.

How do you wash flannel sheets so they stay soft?

Follow the care label first. As a representative example, The Company Store’s instructions for its cotton flannel sheets are:

• Machine wash on a gentle cycle with like colors.
• Use non-chlorine bleach only as needed.
• Tumble dry low and remove promptly.

Low heat is the instruction to keep. Napped fabric already wears faster than smooth weaves, as the encyclopedia entry above notes, so gentler handling helps the nap last. Removing sheets promptly also cuts down on wrinkles.

Expect some lint in the first few washes. L.L.Bean says lint in the dryer screen “is a natural result of brushed flannel construction,” and claims its sheets “get even softer with every wash.”

Are flannel sheets too hot for some sleepers?

They can be. The nap exists to hold still air, so people who sleep warm may find flannel stuffy on milder nights. In that case, save flannel for the coldest months and switch back to cotton percale or sateen in spring.

For cold sleepers, flannel is one layer in a stack. A brushed sheet, a warm throw from our throw blanket guide and a pre-warmed bed often beat turning up the thermostat. You can warm the bed with a hot water bottle used safely or a heated throw; read whether heated throws are safe before leaving one on overnight.

If you are rethinking the whole bed, our guide to silk pillowcases and momme weight covers the other fabric that shows up in bedding searches, and how to make a room feel cozy covers light, texture and drafts.