One of the questions we get asked frequently is "Will an item be the same size after it is washed?"
As many consumers know, cotton fabric and cotton fabric blends can lose some of their dimensional size once washed and dried. Another element to consider - is that stated dimensions are based on the item being 100% flat and pulled tight in all 4 directions. When bedding is filled with it's filling material you also lose some of the stated size. So we will explore both topics to help you make a better buying decision.
Why does fabric shrink?
Usually items made with 100% cotton or a high-blend rate have noticeable shrinkage due to the nature of the material and how it is woven. Typical washing and drying of an item will reduce the stated size by appx 5-10%. We often encourage folks to use protectors on your bedding, like pillow protectors for your pillows and duvet covers for your comforter or duvet insert. This allows the outer protector to be washed rather than the inside item, resulting in products that stay bigger longer.
According to one source, "Cotton shrinks after the first wash due to the chemical tension that was applied to the fabric and yarn during its production. Because of that process, most cotton items will shrink from the heat and steam in washers and dryers."
Why does filled bedding measure less than stated?
For legal requirements, sizes are shown in their unfilled state. So for example, an oversized king comforter might measure as 107 x 96, but if taken home and measured on a flat surface like the floor, the actual dimensions might measure 104 x 92. This is because once the fabric is filled, the sides of the comforter shrink due to the internal volume expanding vertically. So actual surface dimensions measuring the hills and valleys or bends in the product would still be equal to the stated dimensions.
It is important to know the size of the duvet cover and pair it with a duvet insert that will fit it. To make it even more confusing, the duvet cover itself is likely to shrink from washing and drying. So the best thing to do is match them in size - ideally within plus or minus two inches (a bigger size comforter or duvet insert always better). So that cute duvet cover from Pottery Barn measuring 104 x 90 should be paired with a duvet insert measuring 104 x 90 (even better is 106 x 92).
It is also worth pointing out that adding a duvet cover to a comforter adds its own level of warmth, so take that into consideration and perhaps not use the heaviest level of warmth for your duvet insert or comforter, knowing that the total warmth offered will include the comforter or duvet insert plus the layers of fabric from the duvet cover.
A comforter = duvet insert with no tabs
A duvet insert = comforter with tabs
So if you have a duvet cover - buy a duvet insert. If you don't use a duvet cover - you can use whatever you like.