We get calls all the time from people who want to know if you need a special cover to protect against dust mites. They may already have a cover or pad on the mattress or pillow and want to know if it will do the trick. I don’t blame them for asking. I wouldn’t want to buy a new mattress cover if the mattress cover I already owned would do the trick.
The problem is most regular mattress covers aren’t made of barrier cloth. Barrier cloth is the common name we give to microweave fabrics. The idea of a mattress cover made of a microweave is that the fibers have been woven so tightly that the allergens cannot escape through as air flows.
The most tightly woven microweave mattress covers are made from polyester fibers. That is because polyester is a strong yarn that can be woven very tightly without breaking. To get allergen protection, you want a mean (average) pore size of at least 8 microns.
The good microweave mattress covers are made with fabrics that have a 5-micron pore size and the really really good ones have a pore size of 4 microns. Of course, if you don’t like the idea of a mattress cover made from polyester and want the coolness of cotton, then you will have to sacrifice some pore size.
So, if the mattress cover you currently own totally encases the mattress, zips closed, and is made from a fabric with a mean pore size of under 8 microns, then you do not need to buy a special cover. Chances are, your cover does not meet these requirements and the money invested in a new mattress cover will well be worth the relief you get from sleeping allergy-free