Guide to buying the best dehumidifier for your home

How to buy the best dehumidifier

What is a dehumidifier?

Wet air indoors can be harmful to your health and your property, whether it’s a humid summer day or a wet stormy night. Damp indoor air can make your skin feel hot and sticky, make the air feel muggier and more difficult to breathe, trigger allergies and encourage mould to grow around your home. Mould is a serious problem itself, causing major damage to your walls, windows, grout lines, foundations and more.

Why do I need a dehumidifier?

If you’re noticing musty smells, dust mites, mould and mildew, condensation on windows and wet, heavy-feeling air in your house, it might be time to get a dehumidifier. Dehumidifiers remove moisture from the air to maintain an appropriate level of humidity indoors. They suck in moisture-filled air from a room, filter the water out, then blow the drier air back into the room.

What type of dehumidifier should I buy?

There are two main types of dehumidifiers in Australia.

Refrigeration dehumidifiers

Refrigeration dehumidifiers are the most common type of dehumidifier in Australia. These dehumidifiers draw warm, moist air inside the unit, then filter it over cold coils or pipes. As the air cools, the airborne moisture turns into water and drips off the pipes into a collection tank.

Pros: These dehumidifiers outstrip the competition in hot, humid weather. Several refrigeration dehumidifier models can extract 30L+ of moisture per day.

Cons: Refrigeration dehumidifiers aren’t as effective in cooler weather. If you live in areas where temperatures regularly drop below 20°C, this type of dehumidifier may not be your best choice. They also tend to be bulkier and heavier than desiccant dehumidifiers.

Dessicant rotor dehumidifiers

Desiccant dehumidifiers draw in moist air and push it past a wheel, disc or belt made of desiccant material, like the silica gel sachets found in boxes with electronics or vitamins.

Pros: Air temperature doesn’t affect desiccant rotor dehumidifiers: they work just as well in hot, humid conditions as in cool, damp climates. They also tend to be quieter and more lightweight.

Cons: Desiccant rotor dehumidifiers typically aren’t as effective as refrigeration dehumidifiers in hot temperatures. They are also potentially less energy efficient than refrigeration models.

Do I need a dehumidifier if I have an air conditioner?

You may not need a dehumidifier if you have an air conditioner that is good working order and regularly serviced. “It’s important to clean the filter on your air conditioner regularly to keep it operating efficiently and effectively,” says Head of RACV Trades Kieran Davies. “Having your air conditioner serviced every couple of years will also ensure the unit keeps working well over the years and avoid nasty surprises.” 

Air conditioners dry the air as they cool it, and reverse-cycle air conditioners sometimes have a dehumidify mode. Since dehumidifiers tend to heat the air when in operation, you might need to turn on the air conditioner at the same time.

“Exhaust fans are a great and relatively cheap way to move humid air out of areas like bathrooms, kitchens and laundries,” Davies says. Turn on your kitchen exhaust fans when cooking meals that produce steam, and run your bathroom exhaust fan for 10-15 minutes during and after a hot shower.

Your clothes dryer should also be appropriately vented when in use. “With fans, keep in mind that these should be sized appropriately for the room, should draw air into an appropriately ventilated roof space or outside, and should be installed by a qualified electrician,” Davies adds.

Which features do I need in a dehumidifier?

Ability to adjust relative humidity

Dehumidifiers come with a humidistat, which allows you to set the relative humidity (RH) for the room. Ideal RH for human comfort is around 40 per cent. Anything lower than 40 per cent can make the air too dry, causing dry skin, eyes and nasal passages, while anything over 50 per cent can cause bacterial growth like mould. That’s why dehumidifiers with precise RH number settings are best: you can set the RH safely and comfortably in the 40s.

Water collection and drainage

Review the dehumidifier's water collection and drainage features. If you intend to run your dehumidifier all day in the same location, an adaptor hose will pour the water straight down a drain and save you from emptying the water collection tank every few hours. If you want to move the dehumidifier around, the tank should be easily removable and hold at least 4L of water before needing to be emptied.

Air filters and UV light filters

Some dehumidifiers come with air filters to trap dust and/or UV light filters that eliminate airborne bacteria. This is especially helpful if anyone in your home suffers from asthma, allergies or other respiratory problems.

Quiet operation

Make sure that the dehumidifier's decibel level won’t interfere with daily activities like talking on the phone, working from home, watching television or playing an instrument.

Suitability and effectiveness for your home or room

You should also consider how effective the dehumidifier will be in your typical household conditions. Product listings will often highlight the dehumidifier’s performance in ideal conditions. Many dehumidifiers’ performance worsens as the temperature gets lower.

Portability

Finally, look at your dehumidifier’s portability. If it’s too large to comfortably carry, it should come with wheels and handles for safe moving around the home.

How much does a dehumidifier cost?

Dehumidifiers typically cost between $200 and $900 depending on the size and model. You may be able to save some money by buying the right size dehumidifier for your space but remember that it’s better to buy an oversized capacity than an undersized one.