A duvet is basically a sack of feathers and down that resembles a comforter but insulates better and is generally lighter.
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Life is easier when you sleep under a duvet -- your feather or fiber-filled, puffy quilt, covered in soft cotton -- a top sheet and comforter all in one. Just pull it away before getting into bed at night, and shake it out neatly in the morning: Voila! -- your bed is made. Sleeping under a duvet is cozy and comfortable, a tradition learned from Europeans who wouldn't think of sleeping under the layers that most Americans do.
Hunker

Silk duvets let your skin breathe while you sleep. Pure mulberry silk duvets allow some of your body heat to escape, so you will stay warm and comfortable all night long without overheating. On the other hand, a down duvet is designed to do only one thing well: trap heat inside the duvet cover. This can leave you feeling hot and sticky on warm nights.
A silk duvet can mold to your body. Silk duvets are softer and less rigid than a down duvet
Silk has excellent moisture wicking properties which can draw moisture away from your body. This makes silk bedding ideal for year-round comfort. It keeps you cool in the summer and warm in the winter time.
Silk Duvets vs Down Duvets | Silk vs Down Duvet | Manito Silk

Cover Materials
Duvet cover sets include envelopes of fabric large enough to contain the duvet, along with one or more coordinated pillow shams.

Silk - Hard to maintain, stains easily

The Best Fabric for Duvet Covers | Hunker

Cotton:
Cotton is a natural fiber which will become more comfortable and soft with each washing.
Fine cottons such as Egyptian or Supima cotton are considered amongst the finest quality

Egyptian cotton represents a strain with blossoms that are more long than round. It's an excellent choice to weave into bedsheets, towels and other household linens thanks to its extra-long staples, or fibers. type, either percale or sateen. Also look for the label that signifies 100 percent Egyptian cotton. The logo appears in a triangular shape with a cotton ball inside it and the words "Egyptian Cotton" at the base of the triangle.

Organic Cotton does not use any man-made fertilisers or pesticides to grow and is harvested using sustainable cropping methods. This helps to stop people absorbing chemical toxins that can cause allergies, breathing difficulties and skin rashes as well as helping to reduce people's carbon foot print.Technically, Egyptian cotton can be organic, but it is difficult to determine whether cotton from this region is truly organic. Because Supima is produced in the United States, its organic claims are easier to verify.

Percale vs. Sateen weave:
A sateen weave is created by weaving 4 threads over 1. and is known for its luster and drape. The sateen weaving method produces fabric 4 times faster, thus 4 times cheaper than a traditional percale, or balanced weave.
However, while initially very soft and smooth feeling, a sateen fabric will usually pill and become limp or raggy feeling after a few launderings.

Percale fabric is lighter in weight and more breathable.

A sateen bed sheet that claims a thread count of 400 will have 80 threads in the length direction and 320 threads in the width direction. A 400 thread count percale, or balanced woven, bed sheet will have 200 threads woven together in each direction.
Percale vs. Sateen Sheets: The Difference | Thomas Lee Ltd.

Thread count: - the numbers of threads per inch - ranges from 200 to 800 based on the weave
Generally, the higher the thread count, the softer the sheet, and the more likely it will wear well-or even soften-over time. Good sheets range anywhere from 200 to 800.

For both cotton and microfiber sheets, the higher the thread count or the smaller the denier (thread diamater), the higher the quality.
Typically a thread count of 300 or higher indicates a good quality sheet, which in turn will be more comfortable and soft to the touch.

Thread count (TC) is the sum of the warp (vertical) and weft (horizontal) threads are interlaced evenly into a basic basket weave.
They are not always equal. Sateen will frequently have a more weft threads. e.g. a 400 thread count sateen may have 240 weft threads per inch (TPI) and 160 warp TPI.
For Percale it is more common to have equal warp and weft count.

Higher thread count is not always better.
An honest 250 thread-count sheet set has 125 vertical threads and 125 horizontal threads. A 750 thread-count sheet set ALSO has 125 vertical threads and 125 horizontal threads! But in this situation, the manufacturers simply creates a thread that has 3 plys (think of a thread made of 3 threads twisted together) and then TRIPLE-counts the thread.
Thread-Count: Why Everything You've Heard is a Lie! - Authenticity 50

See also Fabric Structure - Textinfo

Poly Cotton is a mixture of cotton and polyester material. Polycotton was developed to get the best of both worlds with the softness of cotton and the ease which polyester can be washed and dried.

Microfiber is composed of very finely woven fibers, finer than silk. They can be made from wood pulp, or polyester and nylon polymers.
Microfiber sheets are very thin, but are strong and exceptionally smooth and comfortable.
The way the fibers are woven determines the quality of the fabric. When woven in a flat weave, microfiber repels water, but when woven into a waffle pattern, after splitting the threads, the resulting fabric becomes super absorbent. Microfiber cloths work well for household cleaning, because the material also acts as a magnet for grime and dirt.
You can now buy microfiber bedsheets that provide an extra-soft sleep, but if you prefer cool crispness, opt for 100 Egyptian cotton percale sheets. Cotton is cooler because it breathes better; microfiber sheets retain body heat, which could affect your ability to get a good night's sleep. See,
100 Percent Egyptian Cotton Vs. Microfiber | Home Guides | SF Gate
Choosing Your Sheets: Cotton vs. Microfiber | AustinLinen.com

Other types:
Egyptian cotton - most expensive, superior & most popular fiber.
Pima (or supima) cotton - grown in the southwest US and Peru. Shorter than Egyptian cotton, but still yields a fine, soft product.
Muslin cotton - the lower end of cotton. Inexpensive, rough and tough.
Silk - strong, durable, natural fiber which gives a smooth, soft texture. Expensive and vulnerable to static cling.
Linen - plant fiber which is very cool and resilient in hot weather.

Eco Friendly Fibers:
The textile industry is the second largest industrial polluter, second only to oil.
See Eco Friendly Linnens for a list of recommended fabrics


Products:
Duvet Covers (Queen):
Duvet Covers | The Company Store

200-thread count cotton percale  $89 
200-thread count organic cotton percale    $99 
400-Thread Count Cotton Sateen $149
300-Thread Count Organic cotton Sateen  $199
600-Thread Count Egyptian Cotton Sateen $239
Linen Duvet Cover Set - Fieldcrest® : Target $104
Linen Duvet Cover | brooklinen $229
ADuvet Set, 1000 Thread Count 100% Egyptian Cotton - Macy's $179

 650 Thread Count Egyptian Cotton Solid Duvet Cover Set - Walmart.com $49

Patterned covers are usually more expensive than pain ones.

Blankets

Links:
Budget Basics: The Best Organic Bedding Under $100 -- Shopper's Guide | Apartment Therapy
Eco Friendly Linnens
Organic Bedding | Bamboo Bedding | Ultimate Green Store

Some samples:
Chic Home Brooklyn Duvet Cover Set - JCPenney
SUPER SOFT BRUSHED MICROFIBER FABRIC,

Martha Stewart Collection Stonemeadow 100% Cotton Ikat Flannel Bedding Collection, Created for Macy's - Duvet Covers - Bed & Bath - Macy's
two ply cotton flannel
$49

last updated 1 Jan 2018