Thinking of a humidifier for dust allergy? It can make dust mites worse.

Dry air can feel rough on a blocked nose, so a humidifier seems like the obvious fix. But dust mites do not drink water. They absorb moisture from the air, and humid air is exactly what they need to survive and breed. For dust mite allergy, you want the opposite: a drier bedroom.

Why humidity matters so much to dust mites

Dust mites thrive when relative humidity is above about 60% and struggle to survive when it stays below about 50%. UK bedrooms are often damp, especially in autumn and winter when windows stay shut and the heating goes on, which is why dust mite symptoms tend to peak from October. Adding a humidifier pushes the air further into the range mites love.

The humidity to aim for

Keep your bedroom between 40% and 50% relative humidity. That is comfortable for you, and hard going for dust mites. A cheap hygrometer will tell you where you are. If you regularly see 60% or more, or condensation on the windows in the morning, your bedroom is helping the mites.

What to use instead

1. A dehumidifier in the bedroom. It pulls moisture out of the air and keeps the room below 50%, so the mite population shrinks over time.
2. Air the room every morning. Pull the duvet back and open a window for 15 to 20 minutes so the night's moisture can escape the mattress and bedding.
3. Seal the bed. Your mattress, pillows and duvet hold the most mites. Encasements trap the ones already inside and keep new ones out, from the first night.
4. For dry, sore airways at night, speak to your pharmacist about saline nasal sprays rather than raising the humidity of the whole room.

Use this instead of a humidifier

Anti Dust Mite Dehumidifier

Keeps your bedroom below 50% humidity, the level dust mites cannot thrive in. From £139, free next-day UK delivery.

Shop the Dehumidifier →

Step 1, biggest impact

Protector Set

Seal your mattress, pillows and duvet. NHS backed, blocks 100% of dust mites.

Shop the Protector Set →

Questions people ask

Is a humidifier good for dust allergy?

For dust mite allergy, usually not. Raising humidity helps dust mites survive. If your air is genuinely very dry (below 40%), aim to bring it up only into the 40 to 50% range and no higher.

Does a dehumidifier kill dust mites?

It does not kill them directly, but keeping humidity below 50% over weeks makes it very hard for them to survive and breed, so numbers fall. Combine it with sealing the bed for the fastest relief.

What about an air purifier?

A HEPA air purifier captures allergen that gets stirred into the air, which helps, but most dust mite allergen is heavy and stays in bedding. Seal the bed first, then add a purifier. See our air purifier guide.

Read next: Dust mite allergy treatments, ranked

This guide is general information, not medical advice. Always speak to your GP or pharmacist before starting, stopping or changing any treatment, especially for asthma or a child. Questions about which products to choose? Call Richard on 0330 122 1646.