Why you should never dry your washing indoors

Wet weather has been battering New South Wales for the past few days and it's looking like there will be more of it coming. We can also expect a wet summer thanks to the return of La Niña.

These are not ideal conditions when you have lots of things to wash and don't have a dryer.

It can be a hassle to deal with when everything feels damp and a majority of homes look like drycleaners right now, with clothes horses and racks loaded up with washing. But this simple task could be filling homes with mould.

Drying wet clothes inside actually creates the perfect environment for mould to grow and spread.

Nicole Bijlsma, Principal of Australian College of Environmental Studies, explained why this happens during a chat with Today Extra's David Campbell and Belinda Russell.

"The cause of mould is moisture, so each wet washing load that you have, each basket is the equivalent to around five litres of water vapour," she explained.

"Each person in that house contributes about 10 litres of water vapour every day.

"So, if you have five people in a two-bedroom apartment, that's 50 litres of water vapour, plus five litres for each load of washing you do, and that apartment may not be designed to deal with that amount of water vapour, which of course could increase the risk of condensation and mould."

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A load of washing might not seem like a huge issue, but when you factor in multiple loads and the number of people it's not hard to see why it can cause mould to grow.

Nicole said the best ways to prevent mould while doing laundry is by using a condensing dryer — which removes water as it's drying clothes — or hanging the load outside if weather permits.

"If you have to port a whole lot of wet washing inside and the humidity is high then obviously a dehumidifier is really important, to pull that moisture out of the air," she explained.

A dehumidifier is your only option if you have to hang your washing inside because it pulls the moisture out of the air.

"It's really important, because as soon as you start getting condensation and that moisture is sitting on the surface for more than 48 hours the bacteria and fungi will start producing chemicals," she said.

What is a dehumidifier?

A dehumidifier is an appliance that essentially removes the moisture from the air, helping to prevent mould.

They draw air in, filter it, cool it to condense the moisture, then reheat it and push the warmer, dryer air back into the room.