Dust Mite Guide › What Humidity Kills Dust Mites?
Dust mites don’t drink; they soak up water from the air, so dry air is what beats them. Keep your home’s relative humidity below 50% (allergy specialists advise 35% to 50%[1]; the Dust Mite Guide recommends aiming for 40%), and keep it there all the time. Mites slowly dry out and can’t sustain their population. A hygrometer tells you where you are, and a dehumidifier gets you there.
Mite bodies are 70% to 75% water by weight, and they get that water by absorbing vapor directly from the air.[1] Humidity is the most important factor in whether a home has high mite levels; in very dry places like deserts, they can’t survive.[2] For the basics of mite biology, see What Are Dust Mites?
A dried-out mite can take water back in within a few hours if the humidity rises, even briefly. Homes that are dry most of the time can still support living mites if humidity rises for as little as 1.5 hours a day, as during cooking.[1] Mites also survive dry periods in a desiccation-resistant stage of their life cycle.[1] That is why low humidity has to be steady, not occasional.
Mites in mattresses and pillows live close to a warm, resting body. One study notes that feeding mites prefer the upper part of the mattress, nearest the sleeper, where temperature is around 32–36°C and humidity is around 55–59%.[4] Keeping the bedroom itself dry, and covering the mattress and pillows, both matter. The guide covers the bedroom step by step.
Use a hygrometer, a small device that measures relative humidity. Allergy specialists recommend that dust mite–allergic patients use one at home.[1] Humidity can differ between rooms and floors, so the guide suggests placing several around the house, including the bedroom.
This page does not recommend specific brands or products. The guide’s dehumidifier section explains what features to look for.
No. Mite allergens are highly stable for long periods, so even if the mites die, allergen already in bedding, carpet and furniture stays until it is washed or removed.[1] Lowering humidity stops new allergen from being made; Chapter IV of the Dust Mite Guide covers removing what is already there. Air purifiers don’t help much with this; see Do Air Purifiers Help With Dust Mites?
Mites slowly dry out when relative humidity stays low, though they can survive for weeks before they die. Allergy specialists advise keeping home humidity between 35% and 50%, and the Dust Mite Guide recommends aiming for about 40%. It has to stay low consistently.
Indirectly. A dehumidifier keeps the air too dry for mites to take in the water they need. In one study, homes kept below 51% humidity, mostly with a dehumidifier and air conditioning, saw live mites fall from about 401 to 8 per gram of dust over 17 months.
A dehydrated mite can take water back in within a few hours if humidity rises, and homes that are dry most of the time can still support mites if humidity rises for as little as 1.5 hours a day, as during cooking.
No. Mite allergens are highly stable, so allergen already in bedding, carpet and furniture stays until it is washed or removed.
Use a hygrometer, a small device that measures relative humidity. Allergy specialists recommend that people with dust mite allergy use one at home.
Also see Do Dust Mites Bite?, More Than Allergies and Dust Mite Poisoning.
Get the free, practical plan: Read the Dust Mite Guide →
This page is for education only and is not medical advice.