Dust mites are members of the spider family. They live in carpet, upholstery, and fabric, and they thrive on human skin scale, animal dander, and trace nutrients. They need humidity to live, but they cannot drink water. The ideal temperature range for dust mites to live is 59-95ºF (15-35ºC) with relative humidity ranging from 55%-85%. Generally, the more humid an area, the more dust mites you’ll find.
It is the fecal matter of the dust mites that causes allergy problems. Common reactions to high levels of dust mite fecal matter include asthma and rhinitis. The approximate number of people in the United States suffering from allergies (not necessarily caused by dust mites) is 50 million and continuing to rise.
There are many products sold to reduce mite population in homes. Although many products do reduce the level of dust mite population, these products do not reduce it enough to have an effect on the clinical symptoms of allergies. The real reduction of clinical symptoms of allergies can be attributed to reduction in humidity, not the products available on the market.
A study was done in Dayton, Ohio in 1995, which tested home humidity levels on dust mite populations. It was discovered that the homes with the air conditioning on and dehumidification set up were the homes with the least amount of dust mites (after 4 weeks, there were zero live mites counted). The second best were the homes with only air conditioning and no dehumidification. The third of course were the homes without any air conditioning and no dehumidification; these homes had the highest levels of dust mites.
The conclusion is that when indoor humidity is kept below 50% Rh, evidence indicates that the mite population does not grow on significant levels. Constant dehumidification is needed to keep Rh below 50%.
The lower the humidity, the drier the air. This may cause severe stuffiness and cold symptoms in many adults and children, which is not necessarily good. However, it is preferred to allergies caused by dust mite fecal matter.
To eradicate dust mites you will need to do the following:
- Maintain a relative humidity below 50%
- Clean all soft goods (upholstery, bedding, clothing) in hot water. Use dryer set at the highest setting possible to dry clothes.