Yes, microfibre makes you sweat more than natural fabrics. It is very fine polyester yarn, and polyester takes up only 0.4% of its own weight in moisture, against 13% for bamboo viscose: sweat stays on the skin instead of passing into the fabric and evaporating.
If you are here looking for a replacement, Looniva bamboo sheets are made of 300TC viscose certified OEKO-TEX Standard 100 class I.
Why microfibre makes you sweat
The body loses water all night, even when you do not sweat visibly. A fabric that absorbs that moisture moves it away from the skin and lets it evaporate from the outer surface. A fabric that does not absorb it leaves it where it is, and the skin stays wet against the fibre.
Polyester belongs to the second group. Its moisture regain stops at 0.4% of its weight, against 13% for bamboo viscose (Journal of Natural Fibers, 2025). Spinning it very fine, which is what makes a microfibre a microfibre, changes the feel of the fabric but not the chemistry of the fibre: it remains hydrophobic as before.
Density adds to this. Fine filaments pack tightly, and a dense fabric lets less air through. The result, to the touch, is the feeling typical of someone who wakes at three in the morning: warm, damp skin, without a visible drop on the sheet.
In short
- Microfibre is polyester, sometimes polyamide, spun into filaments finer than one decitex
- Moisture regain of polyester: 0.4% of its own weight, against 13% for bamboo viscose (source: Journal of Natural Fibers, 2025)
- It is cheap, needs no ironing, and dries quickly after washing: the three reasons it fills the shelves
- Below 20 degrees at night the difference is barely felt; above 24 it becomes the main reason for waking up
- On the label it reads as 100% polyester: the word microfibre describes the fineness of the thread, not the fibre (source: textile convention, yarns under 1 dtex)
What microfibre is
Microfibre refers to a very fine yarn, below one decitex: less than a gram for every ten thousand metres of thread. It is not the name of a material. The fibre underneath is almost always polyester, in some cases polyamide, and the label shows its real name.
Fineness is used to get a compact, smooth surface with little raw material, and it explains why a microfibre sheet is light and cheap. It also explains the confusion: fine sounds light, light sounds cool, and the chain breaks at the first contact, because coolness depends on how the fibre handles moisture.
Microfibre or cotton: what changes in bed
Cotton absorbs around 7-8% of its own weight in moisture: it takes it from the skin and holds it in the fibre. This is why a cotton sheet on a very hot night can end up damp to the touch, but the skin in the meantime has stayed drier for longer than it would under a synthetic.
Microfibre does the opposite: it stays dry itself and leaves the skin wet. In return it irons itself, does not crease, and withstands hundreds of washes without changing appearance, where cotton thins out after two years.
The full comparison of all fabric families is in our guide on which fabric to choose for sheets.
The pros, which do exist
- Price: a set costs a fraction of a natural-fibre set of the same size, and it is the number one reason people buy it.
- No ironing: it comes out of the washing machine already smooth, a real advantage on a bed made every day.
- Dries quickly: useful at home without a tumble dryer and in second homes used now and then.
- Durability: colours and weave hold up over time, even with frequent washing at high temperatures.
The cons, in order of weight
- Moisture management: it is the flaw that decides everything else, and you feel it every night above 24 degrees.
- Air does not pass: the dense weave of fine filaments closes the microclimate between body and fabric.
- Static electricity: in winter, in dry rooms, the fibre builds up a charge and attracts dust.
- Odours: synthetics hold on to body odours more than cellulose fibres, and release them less in low-temperature washing.
- Feel: smooth but slightly rubbery, and with damp skin it tends to cling.
When microfibre makes sense
In cool, ventilated bedrooms, for people who do not overheat at night, the difference from a cheap cotton is small. It also makes sense for spare bedding, for seaside homes left empty a few weeks a year, and for guest beds used twice a year, where practicality matters more than long-term comfort.
It makes little sense for the bed you sleep in three hundred nights a year, and none on summer nights. On that front, the comparison of fabrics that really keep you cool is in our guide to summer sheets.
How to tell if your sheets are microfibre
The first place to look is the composition label: if it says 100% polyester, that is what it is. If it says only microfibre, the fibre must be looked for on the product page, because microfibre on its own is not a valid composition.
Without a label there are two clues. Weight: a synthetic double sheet weighs noticeably less than one in cotton or viscose of the same size. And water: a drop placed on the taut fabric stays on the surface for a long time on a synthetic, while on cotton, linen and viscose it is absorbed within seconds. The same reading method applies to regenerated fibres, as explained in our guide on how to recognise real bamboo viscose.
Frequently asked questions
Is microfibre polyester?
Almost always. Microfibre describes the fineness of the yarn, below one decitex, and the fibre under it is polyester in the vast majority of cases, polyamide in some. The composition label gives the fibre's name: if you read 100% polyester, you have a polyester microfibre.
Are microfibre sheets for summer or winter?
They work better in winter, in cool rooms, where poor breathability matters less and the fibre keeps a little warmth. In summer they are the worst of the common choices, because sweat stays on the skin. The guide to fabrics suited to hot nights covers the alternatives.
Are microfibre sheets bad for you?
There are no reasons to consider them harmful in themselves, and a fabric certified OEKO-TEX Standard 100 is tested for substances that are harmful on contact with the skin. The issue is comfort: people with sensitive skin or who sweat a lot tend to feel better with fibres that move moisture away. For skin conditions, the advice of a doctor applies, not that of a label.
Why are microfibre sheets so cheap?
Because polyester is a petroleum-derived fibre, produced continuously and at low cost, and fine spinning gives a covering fabric with very little raw material per square metre. A set weighs almost half of a natural-fibre set of the same size.
Edoardo Guarise