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How to protect your home from damp, moisture and mould

Our expert tips for preventing and treating mould before it takes hold.

illustration_of_different_ways_to_prevent_moisutre_and_mould
Last updated: 07 May 2024

Need to know

  • Warm days and high rainfall are perfect conditions for mould and mildew. Dehumidifiers, air conditioners, ceiling fans and portable pedestal fans can all be useful to help stop the spread
  • Many 'mould-killing' products in the supermarket don't contain the required amount of bleach to actually kill the mould
  • If you only clean the visible signs of mould and don't solve the underlying causes, such as poor ventilation or a structural problem, the mould will keep returning

Following the wet summer, many of us have started closing up our windows against the winter chill.

But the Bureau of Meteorology is predicting above-average temperatures across most of Australia this winter.

Between the wet summer, the warmer winter, and the reduced air flow in our homes, you might be bracing for the mould and damp that spring up on walls and ceilings, in cupboards or in bathrooms. 

Mould is not only unpleasant and unsightly, but it can also become a health hazard if it gets out of control

Mould is not only unpleasant and unsightly, but it can also become a health hazard if it gets out of control. 

It can wreak havoc in your home if unchecked, so it's important to try to get on top of it early, especially if you've noticed signs of high humidity in your home, such as condensation on windows, wet patches on walls, a musty smell or mildew in the bathroom and on surfaces (including your clothes and soft furnishings). 

CHOICE experts share their handy tips for what you can do to prevent mould before it even takes hold, as well as hsome products and appliances that can help you deal with damp and mould (plus those that won't), how to clean it off yourself – and when to call in the experts.

How to prevent mould and damp 

The best way to protect your home from mould and damp is to prevent it from forming in the first place. (We explain further down how to minimise the spread and manage it once it's taken hold.)

You can't control the weather, but you can control what's happening inside your house to a certain degree (except for in a flood or extreme weather event, obviously!). 

Our tips

Here are some tips for stopping mould and damp before they become a problem:

  • Do what you can to minimise moisture entering your home: check for broken tiles and roof leaks, clear out your gutters and downpipes, assess the state of your windows and external doors and install weather seals if needed. 
  • Ensure good ventilation: keeping air flowing through your house will help prevent humidity and therefore moisture and mould. Open up the house when you can to air it out. 
  • Avoid drying clothes indoors: this will add to the humidity in your home. If you just can't avoid it, you can use a dehumidifier on 'laundry' mode or a dryer. (See next point about what to buy.) 
  • Buy a heat pump condenser clothes dryer: vented dryers pump humid air back out into the room, but heat pump condenser dryers condense the moisture and collect it in a reservoir. They're more expensive to buy but can help minimise moisture. 
  • If buying one of these dryers isn't an option, check to see if your vented dryer can be fitted with a venting/ducting kit to redirect the humid air outside.
  • Install an exhaust fan in your bathroom: this will help minimise the humidity. They're also a good idea for your laundry if you're using a vented dryer.
  • Make informed choices about heating and cooling: unflued gas heaters can release moisture into the air, and having your air conditioning set to freezing when it's boiling outside can cause condensation to form. 
  • Keep on top of the cleaning: mould needs organic matter to feed on, such as dust, dead skin cells and pet dander, so try to dust and vacuum regularly. 

Appliances that can help you prevent or manage mould and damp

Even if you've done everything you can to prepare your home, chances are you could still find yourself dealing with mould, mildew and damp this winter.

But some appliances can keep a lid on the humidity – here's what to use and how to use it to prevent mould from taking hold.

Dehumidifiers

If you have persistent damp problems – and especially if you're renting and can't renovate – or you've suffered a leak or mild flooding, then a dehumidifier can really help. It essentially works by removing moisture from the air, which helps to prevent or minimise mould. 

There are two different types of dehumidifier: refrigerant dehumidifiers are best for hot, humid conditions; desiccant dehumidifiers are best for cold, damp conditions. 

Dehumidifiers aren't always cheap – they can range from less than $200 up to over $1000. 

Almost all the models our experts recommend cost $500 or more. The cheapest models tended to perform poorly, with the cheapest dehumidifier we tested scoring just 3% for water removal. 

But don't buy on price alone: spending more isn't necessarily a guarantee of good performance. 

But don't buy on price alone: not all the expensive models make our recommended list, so spending more isn't necessarily a guarantee of good performance. 

Our expert dehumidifier reviews include information about features, running costs and capacity, and let you sort models by humidifier type, brand and price to help you choose the right one for you.

Air conditioners

Most people think of air con in terms of summer, but it's actually the most cost-effective way to heat your home in winter. 

Air conditioners dry the air as they heat or cool it, so they do have some dehumidifying properties. 

Many models actually have specific dehumidify or 'dry' modes (a mild cooling mode that focuses on dehumidification), so check your manual before you drop any cash on a dehumidifier. 

Ceiling fans and pedestal fans

Good air flow is vital to keeping mould at bay, and ceiling fans are an efficient way to keep air moving in your home. They're also inexpensive to run, averaging $25 a year for AC (alternating current) and $12.87 a year for DC (direct current). 

Ceiling fans aren't just for summer. When you run a heater, the hot air naturally rises up towards the ceiling – which obviously doesn't help keep you warm down on the floor. 

But switching your fans to 'winter' or 'reverse' mode at the start of the cold season will circulate the warm air through the room, keeping you warmer and making your heater run more efficiently. Running a heater and ceiling fan together can slash your winter heating costs.

And even though you can spend hundreds of dollars on a designer model, a number of ceiling fans recommended by our experts cost $350 or less. 

Ceiling fans are an efficient way to keep air moving in your home. They're also inexpensive to run

Even cheaper to buy and run are pedestal fans, which can be handy if you want to direct a blast of air at a specific area that needs ventilation. And running a fan on low for eight hours a day for six months of the year will cost less than $10 for many fans. 

You can pick up a pedestal fan that scores well in CHOICE pedestal fan reviews for as little as $17. 

How to clean mould yourself – and when to call in the experts

When you spot mould forming on surfaces, your first instinct may be to head to the supermarket and throw every cleaning product that has the word 'mould' in its name into the trolley.

This can be a costly exercise, and CHOICE experts say it's also unnecessary.

"Most commercially available mould cleaning products use bleach (often listed as sodium hypochlorite) as an active ingredient, but the concentration of bleach in these products marketed as 'mould killers' is often five percent or less," CHOICE expert Ashley Iredale says.

Bleach can simply take the colour out of fungi, which can make it invisible, but it's actually still lurking there

Ashley Iredale, CHOICE cleaning expert

"While they will probably help remove mould from the surface you're cleaning, you need a concentration of bleach to be at about 10% to kill fungi. 

"Bleach can also simply take the colour out of fungi, which can make it invisible, but it's actually still lurking there."

Don't underestimate vinegar and water

You don't need to fork out more money for specialist mould-cleaning products, as a standard cheaper multipurpose cleaner or even a mixture of plain old vinegar and water (80% vinegar to 20% water) applied with a microfibre cloth will do the trick. Vinegar can cause mould to overeat and die.

But if you have a serious mould problem, or it's grown on something super-porous, such as a textile, clothing or furniture, there's a good chance it can't be completely removed and the item may need to be thrown out.

Same goes for mould that's spread its evil spores into your bathroom grout – it can be virtually impossible to get rid of completely, so the area may have to be regrouted.

When do you need professional mould cleaning?

If you only clean the visible signs of mould and don't solve the underlying issues causing it, the mould will keep returning. If you have mild surface mould, regular cleaning and improvements in ventilation (or using some of our methods above) will probably be enough. 

If you only clean the visible signs of mould and don't solve the underlying issues, the mould will keep returning

But if there's dense, black mould covering a significant portion of your home, it's probably time to call in the experts for professional removal. This can be expensive, with costs ranging anywhere from a few hundred dollars to a few thousand, depending on the extent of the problem. 

But then, professionals can help identify the source of the mould and remove it, potentially saving you more extensive damage and pricey repairs down the track.

Tackling mould if you're renting

If you're a renter, and the mould is caused by a leak in the roof, a faulty pipe or gutters or other structural faults, your landlord is responsible for fixing it and remediating the damage. 

But mould isn't always caused by these issues and some landlords tell tenants they're responsible for cleaning the mould themselves, and for keeping the property well ventilated.

There are no clear-cut laws laid out that make landlords accept responsibility for mould

In Australia, landlords have a general obligation to make sure the homes they rent out are in a reasonable state of cleanliness and fit for habitation by the tenant. But there are no clear-cut laws laid out that make landlords accept responsibility for mould. 

If you have a mould problem, report the issue to your landlord or real-estate agent, take photos and – crucially – document any communication in case you need to go to a tenancy tribunal. 

Find out more about black mould and renters' rights.

We care about accuracy. See something that's not quite right in this article? Let us know or read more about fact-checking at CHOICE.

Stock images: Getty, unless otherwise stated.