The average UK home has over two million dust mites feed on the protein from your dead skin scales.
They live in your mattress and pillows, upholstery and to a lesser extent carpet - the only reason you have never seen them is because they are so small the human eye can not see them. It is not the mite that is the problem but their harmful faeces, which are so small that when disturbed can stay airborne for over ten minutes.
Temperature extremes kill dust mites.
The problem with doing this is gaining accessibility to them.
Mites do not like the light and burrow deep into upholstered furniture, primarily mattresses and secondly sofas. Their prominence in carpet is not nearly so high.
Any application of water during cleaning, will at appropriate temperature, kill those mites near the surface. It will also add moisture which will assist the mites to feed and breed, as they need warmth and moisture to survive.
This is why HWE etc will not eradicate the problem, only scratch the surface.
The problem posed by mites is not that of the mite itself, but is the enzyme which breaks down protein in their food, and is found in their faeces.
This attacks the cell bindings in the lungs of humans and can leave them open to later infection.
However, specialist treatment of a mattress and sofa and lesser extent carpet, can ensure 6 to 12 months of freedom from this problem. The enzyme in it's broken down form (as a result of treatment) poses no problem.
Dust mites are mostly prominent in mattresses and secondly upholstered furniture, where they can burrow deep away from light. This poses the problem that conventional cleaning will not eradicate them other than the lesser numbers on the surface.
Wet cleaning can even add moisture which aids their feeding and breeding capabilities, hence the need for specialist treatment.
Carpet will not be home to many dust mites by comparison to upholstered furnishings especially in exposed areas. The place that they are more likely to be found in carpet, is under furniture, where no direct light gets and no cleaning takes place. This is especially true under sofas and chairs. This same lack of cleaning and build up of dust is just the same in these areas with hard floors as it is with carpet, if not more so. Apathy and lethargy being more apparent attitudes to cleaning with hard floor owners!
(Because they have been led to believe “hard floor is healthier"; so doesn't need effort on their part).
A vicious circle has been created.
The problem is not the mite itself, but within the faces, - even smaller particulate dust. This may fall out from beds and sofas etc onto the floor below. If this floor is carpeted at least most of it is trapped and held out of harms way.
If it lands on hard floor it is easily disturbed and laterally enters the room by virtue of any movement causing a draught, then it is airborne and free to enter the breathing zone, and will remain airborne for long periods. The smaller particulate dust is the longer it remains in orbit around our faces.
A simple experiment can demonstrate this function. Pollen, dust mite droppings and other air allergens are microscopic in size, so let's replace them with something more visible to the naked eye - flour or talcum powder.
Sprinkle a little of the selected powder onto a hard floor, then, from a height of about three feet, drop a book onto the floor so that it lands flat, about 6" from the powder. Repeat the experiment substituting a carpet for the hard floor. That little explosion of dust that accompanied the book landing on the hard surface shows what happens with a light foot-fall or any other draught to the microscopic allergens that land on the flooring even whilst it is being cleaned.
And what happened when the book landed on the carpet? Point demonstrated!
The very act of trying to mop a hard floor or vac it causes much air movement, most of the offending smaller particulate matter is made airborne and not removed by the mopping etc.
Vacuuming a carpet will remove large amounts of trapped matter from the pile. It may not remove many dust mites themselves due to their stiff body and leg hairs (which act like glue) and help the mites stay in fabrics resisting suction, but as it is the faeces that is the problem and needs removing, this is achieved.