Know Your Fabrics: What Bed Sheets Are Actually Made Of
6 min read
Around 51% of Australian adults sleep too hot at night at least once a week (OmniPoll, October 2025, n=1,004 Australians 18+, nationally representative, commissioned by REST and Morey Media). If that's you, the swing tag on your sheets is a genuinely useful place to start looking for answers, if you know how to read it.
Most of us buy bedding on how it feels folded on a shelf, not on what it's actually made of or how it behaves four hours into a warm night. This is a fast reference guide to the fabrics you'll actually find on Australian bedding labels: what each one is, how it's made, how it behaves for warmth, moisture and durability, and who it tends to suit. No rankings, no "best fabric" verdict here, just the facts so you can read a label properly. When you're ready to compare fabrics head to head and pick one, our cooling sheets buying guide does that job.
Some fabrics on this list have a published cool-to-touch number. Several don't. We'll flag exactly which is which, because that gap is itself useful information.
1. Cotton
Cotton is a natural plant fibre harvested from the cotton boll and spun into yarn. It's the default most Australian bedding is built from, and the weave it's spun into matters more than most shoppers realise.
Percale is a plain, one-over-one-under weave. It's crisp, matte and generally the more breathable of the two main cotton weaves because the weave itself is looser and lets more air through.
Sateen uses a four-over-one-under weave, which puts more thread surface facing up. That gives sateen its characteristic soft sheen and silkier drape, at the cost of slightly less airflow than percale.
"Long staple" refers to the length of the individual cotton fibre before it's spun, not the weave. Longer fibres (as in Egyptian or Pima cotton) spin into finer, stronger, less pill-prone yarn. It's a fibre-quality descriptor, separate from thread count.
The short version: cotton is soft, durable, widely available and easy to care for. On the SGS cool-touch comparison chart, cotton tests at Qmax 0.11 W/cm², below the 0.18 W/cm² threshold generally accepted for a fabric to be considered cool to the touch. It also absorbs moisture rather than moving it away, which is why a cotton sheet can feel fine at 10pm and damp by 3am.
2. Linen
Linen is woven from flax, a bast fibre pulled from the stalk of the flax plant (not the seed, like cotton). It has a naturally loose, textured weave, a matte, slightly nubbly hand-feel, and softens noticeably with every wash.
Linen's loose weave allows a lot of airflow, which is why it's popular in warm, humid parts of Australia. It also has a reputation for moisture-wicking, letting the fabric release moisture back into the air rather than holding onto it the way cotton does.
The short version: linen is not on the SGS cool-touch comparison chart. There is no published Qmax figure for linen, which means its cool-to-touch performance simply hasn't been measured and benchmarked the way cotton, bamboo and silk have. That's not a mark against it: linen's breathability through its open weave is real and well suited to some sleepers and some climates. It's a different property to first-touch coolness, and worth knowing the difference between the two before you buy on the word "breathable" alone.
3. Bamboo
Here's where a label can be misleading if you don't know what to look for. Almost all "bamboo" bedding on the market, including nearly everything sold under that name in Australia, is bamboo viscose (also labelled bamboo rayon). It starts as bamboo pulp, which is dissolved in chemical solvents and re-extruded into a fine fibre. That makes it a chemically regenerated cellulose fibre, not a natural bast fibre spun directly from a plant stalk the way linen is. This isn't a criticism, it's simply an accurate description of the manufacturing process, and it's worth knowing before you pay a premium for the word "bamboo" on a tag.
The process gives bamboo viscose a smooth, silky drape and a soft hand-feel that's often marketed as "naturally cooling."
The short version: on the SGS cool-touch comparison chart, bamboo viscose tests at Qmax 0.15 W/cm². That's an improvement on cotton, but it's still below the 0.18 W/cm² cool-touch threshold. The silky feel is real; the cooling claim attached to it is more modest than the marketing usually suggests.
4. Silk
Silk is a natural protein fibre produced by silkworms and spun from a single continuous filament per cocoon, which is what gives it its characteristic smoothness and lustre. It has a long-standing reputation for being temperature-regulating, and it's genuinely gentle on skin and hair. It also needs careful handling: hand wash or dry clean, away from direct sun and rough surfaces.
The short version: on the SGS cool-touch comparison chart, silk tests at Qmax 0.19 W/cm², which clears the 0.18 W/cm² cool-touch threshold, the only natural fibre on this list to do so. It comes with a real durability and care trade-off, and a price point to match.
5. Polyester and Microfibre
Polyester is a synthetic fibre made from petroleum-derived polymers. It's durable, affordable, resistant to shrinking and wrinkling, and widely used across budget and mid-range bedding.
"Microfibre" isn't a separate material. It's a description of fibre fineness, meaning strands spun thinner than standard fibre, usually finer than silk. Most microfibre bedding is very fine polyester, sometimes blended with nylon, woven or brushed into a soft, smooth finish. You can have microfibre polyester, but "microfibre" on its own doesn't tell you what the fibre is actually made from, and it's worth checking the fibre content line on the tag for that.
The short version: standard polyester and microfibre don't have a published Qmax figure on the SGS comparison chart. Untreated synthetic fibre tends to trap heat rather than move it, which is a structural reason "cooling" claims on basic microfibre products deserve a closer look at what, specifically, was engineered to make them cool.
6. Tencel / Lyocell
Tencel is a branded version of lyocell, a regenerated cellulose fibre made from wood pulp, typically eucalyptus. It's worth distinguishing clearly from bamboo viscose above: lyocell uses a closed-loop manufacturing process that recovers and reuses around 99% of the chemical solvent involved, rather than the more open process typically used for bamboo viscose. Both start from plant cellulose and end up chemically regenerated, but the manufacturing footprint differs.
Tencel has a smooth, soft drape and a reputation for moisture-wicking, drawing moisture away from the fibre surface, which is a different mechanism to first-touch cool-to-the-touch performance.
The short version: Tencel and lyocell don't appear on the SGS cool-touch comparison chart, so there's no published Qmax figure for them here. Their strengths are in moisture handling and a soft, silky hand-feel rather than a benchmarked cooling number.
7. Engineered Cooling Fabric
This is a newer fabric category, built differently from the six above. Rather than starting with a natural or regenerated fibre and hoping the weave delivers coolness, engineered cooling fabric is designed from the fibre and knit structure up, specifically to maximise heat transfer away from skin.
Rest's own fabric, Evercool®, sits in this category. It's knitted, not woven, a construction choice that changes how the fabric structure interacts with heat and airflow.
Each product carries its own SGS-tested figure, measured to the JIS L 1927:2020 standard. The Evercool® comforter tests at Qmax 0.433 W/cm². Evercool®+, used in the sheet set and pillowcases, tests at 0.445 W/cm². Both sit well clear of the 0.18 W/cm² cool-touch threshold, and Evercool®+ is over four times cooler to the touch than cotton at 0.11.
Evercool®+ (sheets and pillowcases only, not the comforter) also has fine silver yarn, called Ionic+®, knitted through the fabric. The silver sits inside the fibre itself, not sprayed on top and not a coating that washes out over time. Silver also conducts heat considerably better than standard synthetic fibre, which is part of how the fabric moves heat so effectively. It also helps keep the fabric fresher between washes.
The fabric is OEKO-TEX certified, meaning it's been independently tested for harmful substances (more on what that certification actually covers in our OEKO-TEX explainer). Rest has more than 600,000 customers worldwide.
The short version: engineered cooling fabric is purpose-built at the fibre and knit level to solve the specific problem the other six fabrics on this list weren't designed to solve. You can see how it's put together in more detail on our science page, and the full lab results are on our third-party test results page.
The Fabric Comparison at a Glance
| Fabric | What it is | Cool-to-touch (Qmax, W/cm²) | Moisture behaviour | Typical care |
|---|---|---|---|---|
| Cotton | Natural plant fibre, woven percale or sateen | 0.11 | Absorbs moisture, can feel damp once warm | Machine washable, easy care |
| Linen | Natural bast fibre from flax stalk | Not measured on this chart | Airy weave, releases moisture, softens with wash | Machine washable, wrinkles are part of the look |
| Bamboo (viscose) | Chemically regenerated cellulose fibre from bamboo pulp | 0.15 | Smooth, silky drape | Machine washable, gentle cycle |
| Silk | Natural protein filament from silkworm cocoons | 0.19 | Smooth, breathable in small doses | Hand wash or dry clean |
| Polyester / microfibre | Synthetic petroleum-based fibre, spun fine for "microfibre" | Not measured on this chart | Tends to trap heat unless engineered otherwise | Machine washable, durable |
| Tencel / lyocell | Regenerated cellulose from wood pulp, closed-loop process | Not measured on this chart | Moisture-wicking, soft drape | Machine washable, gentle cycle |
| Engineered cooling fabric (Evercool®) | Purpose-built knitted fibre structure | 0.433 comforter, 0.445 sheet set and pillowcases | Engineered to move heat and manage moisture | Machine washable |
Comparator figures (silk 0.19, bamboo 0.15, cotton 0.11) are from the SGS cool-touch comparison chart. Evercool® figures are from Rest's own SGS test reports, measured to the JIS L 1927:2020 standard. Linen, polyester, microfibre and Tencel do not have a published Qmax figure and are described qualitatively above.
How to Read a Bedding Swing Tag
A swing tag carries a handful of numbers and labels. Here's what they actually mean, and what to skip past.
Fibre content tells you what the fabric is literally made from (for example "100% cotton" or "viscose from bamboo"). It's a legally required line and the single most reliable piece of information on the whole tag.
Thread count measures the number of threads woven into one square inch, and it only applies to woven fabrics like cotton, not to knitted fabric. It's also a number that's easy to inflate through counting method, and it tells you nothing about how cool a fabric feels. We've gone deeper on exactly why in why Rest doesn't use thread count.
GSM (grams per square metre) measures fabric weight, not quality or cooling performance. A heavier GSM can mean a plusher hand-feel or it can mean a warmer fabric, depending on the fibre.
Qmax, when it appears, is the number worth paying the most attention to if you run hot. It's the only figure on this list that directly measures cool-to-touch performance, and the accepted threshold for a fabric to genuinely qualify as "cool to the touch" is 0.18 W/cm². We break the whole measurement down in why your bedding's Qmax score matters more than thread count.
Certifications like OEKO-TEX tell you the fabric has been independently tested for harmful substances, separate from any performance claim.
Care symbols round out the tag and tell you how to actually look after what you've bought. Our guide to laundry care symbols decodes every icon you'll find.
Now You Can Read the Label
Every fabric on this list does something well. Linen breathes beautifully in a loose weave and genuinely suits some sleepers better than anything engineered. Silk is the only natural fibre that clears the 0.18 W/cm² cool-touch threshold. Cotton is the reliable, easy-care default most of us grew up on. None of that is a knock on any of them, it's just what the numbers, where they exist, actually say.
Rest builds Evercool® in the engineered cooling fabric category, knitted rather than woven, tested to Qmax 0.433 W/cm² in the comforter and 0.445 W/cm² in the sheet set and pillowcases, and OEKO-TEX certified. Rest bedding won the 2026 Prevention Australia Health & Fitness Awards, Cooling Sheets category.
If you're ready to put fabric knowledge to work and actually choose between them, our best cooling sheets Australia guide compares cotton, linen, bamboo and cooling-engineered fabric head to head. Or skip straight to a personal match with our 2-minute sleep quiz, or go straight to the Evercool® Comforter or the Evercool®+ Starter Sheet Set.
Whatever's on your bed right now, at least you'll know what it's actually made of.
Frequently asked questions
What's the difference between bamboo and Tencel bedding?
Both start as plant cellulose, but the manufacturing is different. Bamboo bedding is almost always bamboo viscose, made by dissolving bamboo pulp in chemical solvents and re-extruding it as fibre. Tencel (lyocell) uses a closed-loop process that recovers and reuses about 99% of its solvent, which is a more resource-contained way of making a similar type of fibre.
Is percale or sateen cooler?
Percale's plain, one-over-one-under weave and matte finish generally allow more airflow than sateen's four-over-one-under weave, which trades some breathability for a smoother, silkier feel. Neither weave has a published Qmax (cool-to-touch) figure specific to weave type, so this is about breathability and hand-feel rather than a measured cooling difference.
What does Qmax mean on a bedding swing tag?
Qmax (maximum heat flux) is a JIS L 1927:2020 test that measures how much heat moves from your skin into a fabric the instant they touch, in watts per square centimetre. The higher the number, the cooler a fabric feels on first contact. The accepted industry threshold for a fabric to be considered genuinely "cool to the touch" is 0.18 W/cm².
Is microfibre a type of fabric?
Not exactly. "Microfibre" describes fibre fineness, meaning strands finer than a standard fibre, not a specific material. Most microfibre bedding is very fine polyester (sometimes blended with nylon), woven or brushed to a soft, smooth finish.