Two liters, even two and a half liters, so much water that a normal washing machine load, once on the drying rack, gives way to the air in the house. It is not an estimate by eye, given that the data comes from laboratory tests Glasgow Caledonian Universitypart of a three-year study coordinated by the Glasgow School of Art. The measurements were made on a typical load of 15-17 items, i.e. approximately 4-5 kilos dry, at approximately 21 degrees with a relative humidity of 47.5%.
How much does laundry weigh on home humidity
A family of four already produces between 5 and 10 liters of steam per day, just with normal daily activities. According to researchers, the laundry hung inside is worth on average at least 15% of the home humidity over the course of the week and reaches 30% on washing machine days. The bulk goes away immediately, and about 88% of the water evaporates in the first four hours, so a liter already in the first two. How much relative humidity really rises, however, cannot be reduced to a dry number, and the authors warn how much it may depend on other factors, such as the levels of ventilation and/or heating that affected a specific environment (trivial to say: with the windows closed the vapor remains there). Computer models from the University of Strathclyde indicate that, with wet clothes inside a room, an extra 3 degrees would be needed to keep the relative humidity constant. Air vents alone are not enough, and opening the windows with the heating on will only increase consumption.
The spores in the air
The study looked at 100 homes in Glasgow and monitored 22 of them for two weeks. In the cold season, 87% of families hung clothes at home, and two out of three did it on or near radiators. Where they dried all their laundry indoors, the average concentration of mold spores in the air reached 1,398 units per cubic metre, more than double that of those who used the dryer (644) or hung outside (680). Above 1,000 the value is considered high, and Finland sets the limit at 500. In a quarter of the houses theAspergillus fumigatuswhich can cause lung infections in those with low immune defenses. It should be noted that the researchers did not measure the health of the occupants, so the link to asthma and allergies rests on previous literature, not this sample.
What to do
The authors’ advice is the usual: hang out outdoors when possible, prefer efficient condensing dryers, take advantage of south-facing windows and balconies. For those who have no alternatives, the guide suggests keeping the laundry in a separate closed and ventilated space, so that the steam does not circulate throughout the house. We conclude with the advice of the Consumer Protection Center of Bolzano, which indicates a relative humidity between 45 and 55% as a reference.
