III · Humidity · Explainer · 6 min
Dust mites live on humidity
Why keeping relative humidity below 50% is one of the few interventions that reduces mite populations.
By Colpo d’Aria Editorial · Published September 24, 2026 · Last reviewed October 1, 2026
The short answer
Dust mites absorb water from the air rather than drinking. Keep indoor relative humidity below about 50% and populations decline over time. Filtration plays a supporting role.
How mites survive
Mites live in mattresses, pillows, upholstery and carpet, feeding on skin flakes. They have no way to drink; they take moisture directly from the surrounding air. Below roughly 50% relative humidity, they dehydrate faster than they can replace water.
Why humidity is the lever
Research by Arlian and colleagues showed that keeping homes below 50% RH through a humid season substantially reduced mite counts and allergen levels. Many other measures reduce allergen temporarily; humidity addresses the population itself.
What to do
- Measure humidity in the bedroom for a week, including at night
- Run a dehumidifier or air conditioning in humid months to hold below 50%
- Encase mattresses and pillows in allergen-proof covers
- Wash bedding weekly in hot water (at least 130°F / 54°C)
- Reduce carpet and heavy fabrics in the bedroom where practical
Where filtration fits
Mite allergen is heavy and settles quickly, so air purifiers catch little of it. A HEPA vacuum and purifier help around cleaning and bed-making, when allergen is briefly airborne. Keep expectations modest.
A caution
In dry winter climates, do not dry the air so much that airways and skin suffer. The goal is below 50%, not as low as possible.