All homes have dust mites. This is a fact. They live inside your mattresses, couches, anywhere and everywhere. If you do not already have an in-room Air Ionizer, then use your portable Air Ionizer to Detox Bed Daily/Weekly. One Example is to Detox each bed within the home when not in use for a few days straight. You will need a total of 48 hours of ionization to inhibit all the mites. Then take your portable Air Ionizer to a new room to detox a new bed for a total of 48 hours. Ensure Humidity is 40+% throughout the Session. You may need a humidifier with filtered water to achieve consistent 40+% humidity. Afterward, I suggest detox each bed in the home for 8 hours once a week. In a small box, Ionizers got rid of Dust Mites within 2 hours. In a large space, Ionizers got rid of dust mites in 24 hours. Hence Volume is a big deal with air ionizers. More space, more time is needed.
https://www.panasonic.com/global/hvac/nanoe/all/verification/evidence.html
This study shows an air ionizer killing dust mites inside of a mattress like setup. included a foam that was 4.5cm thick, with a dust mite Petri dish.
Direct exposure had much faster liking rates. This is from a no name brand 2012 ionizer.
Panasonic otherwise makes the best consumer ionizer for dust mites. Sharp works too but nowhere near as well. A mini ozone generator would work far better than sharp to be used on occasion/briefly. You can see and possibly check for dust mites in your linen with a basic $10 microscope from Amazon.
Please let me know if you have any questions =)
Regarding volume of air, surely putting an airtight cover/material over the whole bed (or at least the top of the mattress) and putting the ionizer underneath will help significantly reduce the amount of time needed to kill the bed bugs?