The house dust mite covers are made up of several different types of materials. These materials are as following:
Membrane coated or film coated woven.
Membrane or film coated non-woven.
Woven with acaricidal coating
Non-woven with acaricidal coating.
Despite of what manufacturers claim it is important to choose the pillowcases or the covers for the whole bedding very carefully. Not all of the covers are as dust mite resistant as claimed. So it is important to be well informed and know that you are buying the correct one.
The fabrics which are tightly woven are made from twisted cotton or they are made up of synthetic fibers. These fabrics are perpendicular to each other and the weaving pattern is either regular, systematizes bi or tri-axial. If you want to buy the fabric which is most effective in blocking the dust mites from entering the fabric then always prefer to buy the fabric with thread count greater than 246/2 per square inch.
The thread count of any fabric shows the fineness and coarseness of the fabric. The fabrics which are tightly woven have the pore size between 2- 10 m then it means that the fabric will be very effective in keeping your bedding safe from dust mites and majority of the allergens produced by these dust mites will not be able to enter your pillows, your sheets or your duvets.
If you are washing the covers regularly then there is a chance that after a few months of regular washing the quality of the covers will not be the same. If you want more durability of the covers then you should prefer the plastic covers. The plastic covers can withstand the regular washing and there is no effect on the quality of the covers and they are able to protect bedding from the allergens and dust mites. The non-woven fabrics should be avoided because they are not very effective against the allergens and dust mites.