The hot, humid, wet weather currently affecting Queensland and NSW has led to a surge in demand for dehumidifiers, with consumers moving to stop mould growth that also affects clothes stored in wardrobes and drawers.
In Australia, humidity has climbed to the point where some individuals are now seeing traces of mould spreading through their homes.
This has led to a boom in sales for dehumidifiers for retailers.
Mechanical dehumidifiers work by using a refrigerant to cool down a surface inside the machine, or by using a desiccant substance that draws moisture in, which is then dried out via a heating process.
Decent-sized units are not the cheapest, and could set people back between $349 and $3,750 for top end models.
Given the economic climate, and the increase in cost of living, tumble dryers are becoming dearer to use. A dehumidifier can help dry clothes hung up inside the home.
Rachael Peterson, an electronics engineer uses her dehumidifier to dry out clothes hung up in an enclosure under her stairs. She does this overnight and says it’s much cheaper than a dryer.
“The clothes are dried down there in a matter of hours. Everything’s dried properly.”
Professor Cath Noakes, an expert in air quality at the University of Leeds in the UK, says it’s important to ventilate and heat homes as well as using a dehumidifier. She said the ideal relative humidity is between 40% and 60%.
“High humidity is associated with mould and other microbial growth. Very low humidity, say below 40% – and definitely below 30% – is associated with things like respiratory viruses.”
A dehumidifier will not remove mould, just some moisture that could encourage it. If there are leaks or water ingress problems, a dehumidifier won’t fix these issues on its own.
Around 15 years ago, engineer Ray Galvin at the Cambridge Institute for Sustainability Leadership, conducted a study on using a dehumidifier to solve moisture problems in a 1930s house.
The results indicated running the device for around 4 hours each night consumed 1KW hour of electricity and removed over a litre of water from the air.
He said there are other ways of reducing high moisture levels if the person can’t afford a dehumidifier. He suggested the German approach of Stosslüften, or “shock ventilation.”
This involves opening multiple windows as wide as possible for several minutes, allowing a changeover of air inside, then closing them again. He said this won’t cool the house down but will reduce relative humidity.
Dehumidifiers can also be used in more extreme situations including flooding or severe leaking.
Over the years, improvements have been made to dehumidifier motors, compressors, and fan blade designs in an effort to reduce noise levels as well.
