The short answer
- House dust mites absorb water vapour from the air rather than drinking, so relative humidity, not food supply, is the limiting factor in most homes.
- Mites do poorly below roughly 50 percent relative humidity. Brisbane sits above that for large parts of the year, indoors as well as out.
- A cheap hygrometer in the main bedroom tells you more than any product you could buy first. Target 40 to 65 percent.
- Humidity control does double duty: the same range that suppresses mites also sits below where mould gets going, and mould can start within about 48 hours in the right conditions.
- Bedding, mattresses, carpet and soft furnishings are where dust and allergen accumulate, which is why the bedroom is the room to fix first.
- You cannot eliminate dust mites from an occupied home. Lowering the load in the house is the realistic goal.
Dust mites do not drink. They have no mouthparts for it. They pull water vapour straight out of the air around them, which means the humidity of a room decides whether a population expands or struggles. That one piece of biology explains why the standard advice list works well in Melbourne and underperforms here, and why moisture control is the first thing I look at in a Brisbane home rather than the last.
Why humidity is the lever, not vacuuming
Food is rarely the constraint. Dust mites eat shed skin, and every occupied house produces a steady supply of it. Warmth is rarely the constraint either, at least not in this climate. Water is the constraint, and mites can only get it from the air.
Below roughly 50 percent relative humidity they lose moisture faster than they can absorb it back, and populations decline. Above that they do progressively better, and in the 70s they do very well indeed. This is well established, which is why humidity appears in the standard guidance on the subject. The broader picture sits in dust mites and sensitive homes. This article is the Brisbane-specific half of it.
Vacuuming and washing still matter. They remove the accumulated allergen, which is the material that actually sits in the dust and gets stirred into the air when someone walks across a rug. But if the room stays at 70 percent, you are removing a population's output while leaving the conditions that produce it. Do both.
Brisbane makes a good address for a dust mite
Our summers run humid for long stretches, and the wet season pushes indoor readings higher again. Plenty of homes here sit above 60 percent for months at a time. Queenslanders with subfloor moisture, houses on the low side of a gully, and any room that stays shut all day tend to run higher than the rest of the house.
The useful part is the overlap. The range that suppresses mites, roughly 40 to 65 percent, is also the range that keeps you out of mould territory. Mould can begin growing in about 48 hours given the right surface, temperature and moisture. Getting a house into that band is 1 intervention addressing 2 problems, which is unusual and worth taking advantage of. If damp is already visible, start with mould and damp in Brisbane homes instead, because active mould needs dealing with before anything else.
Measure before you buy anything
A hygrometer costs about as much as a decent bottle of cleaner. Put one in the main bedroom, at bed height, not on top of a wardrobe. Leave it a week and look at it morning and night.
You will probably find the bedroom is the worst reading in the house. With 2 people breathing in a closed room for 8 hours, a surprising amount of moisture goes into the air, and the door is usually shut. Bathrooms spike and recover. Bedrooms sit high and stay there.
Readings vary noticeably between rooms, so a meter in the living room is not the whole story. If you only buy a single hygrometer, put it where someone sleeps.
Where the moisture is coming from
Most of it is generated inside, not imported.
- Showers, especially long ones with the door open and no exhaust fan running afterwards.
- Cooking without a rangehood that actually vents outside rather than recirculating.
- Drying laundry indoors, which is the biggest avoidable source in a lot of homes. A wet load releases litres of water into the air.
- Unflued gas heating, which produces water vapour as it burns.
- Subfloor moisture rising into the floor structure, common in older raised homes.
- Poor cross-ventilation, where a room has a single window and no path for air to move through it.
Fix the sources you can before you buy equipment. Running the exhaust fan for 20 minutes after a shower rather than 2 costs nothing and moves the reading.
Ventilate on dry days, not humid ones
Opening the windows is generally good advice that becomes bad advice on the wrong day. If it is 85 percent outside, throwing the house open imports moisture rather than removing it. You are not airing the place out. You are refilling it.
Check the outdoor humidity before you open up. Mid-afternoon is usually the driest part of the day, and winter and the dry spells between systems are when ventilation earns its keep. On a muggy February morning, keep it shut and use mechanical means instead.
Dehumidifiers, honestly
They work. They also have real limits, and people are often disappointed because they expected a whole-house result from a unit sized for 1 room.
A compressor dehumidifier in a closed bedroom, correctly sized, will hold that room in range through a humid night. Open the door to the rest of the house and it will run continuously and lose. They need emptying or a drain hose, they add a little heat, and they use power. Air conditioning also removes moisture as a side effect of cooling, and on many nights running the aircon is the simpler answer. The sizing and running-cost detail is in do dehumidifiers work in Brisbane.
My general position: 1 unit in the room where someone sleeps, door closed, is worth far more than 1 unit in a hallway trying to serve the whole house.
Treat the bedroom as the priority room
You spend 7 to 9 hours a night in direct contact with a mattress and bedding, and those are exactly the reservoirs where dust and allergen accumulate. Carpet and soft furnishings hold plenty too. Nothing else in the house gets that much contact time.
What I recommend, and what we do in client homes:
- 1Hot-wash sheets and pillowcases weekly. A hot wash does 2 things: it removes accumulated allergen and it kills mites in the fabric. A cold wash removes some allergen and leaves the mites.
- 2HEPA vacuum the mattress surface every time the sheets come off. It takes 5 minutes and it is the most useful item on this list.
- 3Fold the blankets and doona back for an hour after waking so the bed airs and the moisture from the night can leave.
- 4Wash or air pillows, doonas and mattress protectors on a schedule rather than never. Most people have never washed a doona.
- 5Consider tightly woven barrier encasements on the mattress and pillows. They restrict allergen moving between the bedding and the room. They are not magic and they need washing too.
What I do not do is wet-clean or steam a mattress. Adding moisture to a thick foam or spring core that cannot dry quickly, in this climate, risks creating a worse problem than the one you set out to solve. Low moisture, mechanical removal, humidity control. That approach is the backbone of our allergy-friendly cleaning work, and the full room-by-room version sits in the bedroom reset.
Filtration matters at the vacuum, not just the air purifier
Dust mite allergen travels on fine particulate. A vacuum with poor filtration lifts it out of the carpet and returns a good portion of it to the room through the exhaust, which is why some homes feel dustier after cleaning than before. Proper HEPA filtration captures that fraction instead of recirculating it. We use professional HEPA machines for exactly this reason, and the difference is not subtle.
You are not going to get rid of them
Every occupied home has dust mites. Homes with hard floors, lower humidity and a disciplined bedding routine have fewer, and the allergen load in the dust is lower. That is the whole game. Anyone promising elimination is selling something.
The realistic version looks like this. Get a hygrometer. Learn what your bedroom actually reads. Stop generating unnecessary moisture indoors. Ventilate when the outside air is drier than the inside air, and not when it is wetter. Run a dehumidifier or the aircon in the bedroom on the bad nights. Hot-wash bedding weekly and HEPA vacuum the mattress while the sheets are off. That is maintainable, and maintainable beats heroic every time.
Beyond Clean Living is a cleaning service, not a health service. Nothing here is medical advice, and cleaning is not a treatment for any condition. What we work on is the home: the dust, allergen and moisture that accumulate in it, which helps reduce common household triggers and supports a healthier home environment. It is complementary to, never a replacement for, advice from your doctor or specialist, and individual results vary.
Where a cleaner fits into this
The humidity side is yours, honestly. I can tell you what the readings generally mean and where moisture commonly comes from in a home like yours, but buying a hygrometer and running an exhaust fan is not something you need to pay anyone for.
What we handle is the accumulation. HEPA vacuuming through the reservoirs properly, including the edges, under the beds and the soft furnishings that get skipped. Fragrance-free products throughout, because adding a fragranced product introduces a trigger while you are busy removing another one. Detail work like vents, blinds and ceiling fans, which hold a lot of settled dust and which we rotate across visits rather than doing every time.
If your home is already in reasonable shape and the humidity is under control, you probably need us less often than you think. I would rather say that up front.
Common questions
What humidity level kills dust mites?
Dust mites do poorly below roughly 50 percent relative humidity, because they absorb water from the air rather than drinking and start losing moisture faster than they can replace it. Sustained low humidity reduces a population rather than killing it instantly. A practical indoor target is 40 to 65 percent, which also sits below the range where mould becomes likely.
Are dust mites worse in Brisbane than in southern Australia?
Conditions here suit them for more of the year. Brisbane humidity runs above the 50 percent threshold for long stretches, particularly through summer and the wet season, so indoor readings often sit in the range where mites do well. Drier southern climates spend more of the year below that threshold, which suppresses populations without anyone doing anything.
Does a dehumidifier reduce dust mites?
It can, if it is sized for the room and the room is closed while it runs. A correctly sized unit in a bedroom with the door shut will hold that room in range overnight. The same unit trying to serve a whole open-plan house will run constantly and achieve very little. Air conditioning also removes moisture as a side effect of cooling and is often the simpler option.
Should I steam clean my mattress to get rid of dust mites?
I do not recommend it and we do not do it. Steam and wet cleaning add moisture to a thick core that cannot dry quickly, and in a humid climate that risks creating a mould problem worse than the one you were addressing. A low-moisture approach works better: HEPA vacuum the mattress whenever you change the sheets, hot-wash the bedding weekly, air the bed each morning, and keep the room humidity in range.
How often should bedding be washed to reduce dust mite allergen?
Weekly for sheets and pillowcases, in a hot wash. Hot washing both removes accumulated allergen and kills mites in the fabric, while a cold wash removes some allergen and leaves the mites behind. Doonas, pillows and mattress protectors need washing or airing on a schedule too, and most households go far longer between those than they realise.
Can you get rid of dust mites completely?
No. Every occupied home has them, because every home produces the shed skin they feed on. The realistic goal is lowering the allergen load in the house and keeping conditions unfavourable through humidity control, regular hot washing, and thorough HEPA vacuuming of the places dust accumulates. Anyone promising complete elimination is overstating what is possible.