Drying Laundry Indoors in a Small Flat Without the Damp

Our first winter in this flat, I found a grey speckle of mould behind the bedroom curtain in mid-January. The window frame was wet every morning, the corner above the wardrobe smelled faintly of a cellar, and Bastian's work shirts took three days to dry on the airer. We do not have a tumble dryer, there is no balcony, and the building's rules ban drying anything on the window railings. So every load of washing was going into the same 38 square meters we sleep, cook and work in.

What I had not done was the arithmetic. A load of washing does not just dry. The water in it goes somewhere, and in a small flat with the windows shut, it goes into the air and then onto the coldest surface it can find. Once I started treating the laundry as a water problem rather than a space problem, the mould stopped coming back.

How much water one load actually puts into the room

I weighed it, because I spent six years in catering kitchens and I trust a scale more than a guess. Our usual mixed load is about 4.5 kilograms dry. Straight out of our machine on a 1,000 rpm spin, the same load weighed 7.1 kilograms. That is roughly 2.6 liters of water, a bit more than a large bottle of fizzy water, all of which leaves the clothes over the next day or two.

When I changed the spin to 1,400 rpm, the wet weight dropped to 6.6 kilograms. Half a liter less water per load sounds minor until you count. We do four loads a week in winter, so that is two liters a week that never reaches our walls. It also cut drying time on the airer by roughly a third, and I have not noticed any extra creasing on jeans or towels. I do keep delicate tops on a lower spin.

The humidity in a room you live in is comfortable somewhere around 40 to 60 percent. Mould starts to settle in when surfaces stay damp and the air sits above about 70 percent for long stretches. On a wash day with the windows shut, our cheap hygrometer used to read 78 percent in the bedroom by evening. That number explained the curtain.

Why the bedroom is the worst place for the airer

We used to put the airer in the bedroom because it was out of the way. It is also the coolest room, the door stays closed all day, and two people breathe out moisture in there for eight hours every night. Cool air holds less water than warm air, so the same amount of moisture pushes the relative humidity much higher in a 16°C bedroom than in a 20°C living room.

We moved the airer to the living room, next to the radiator but not touching it, with the door to the hallway open. Clothes draped directly on a radiator dry quickly, but they push moisture into the room fast and make the boiler work harder against wet fabric. A gap of about 30 centimeters lets the warm air rise through the airer instead.

The question is not where the airer fits. It is where the water can leave the flat.

The advice to "just open a window" did not work for us

Every forum thread says to dry clothes with a window open. We tried it for most of November. The flat got cold, the heating ran longer, and the clothes dried more slowly because the room had cooled down. The window frame by the airer collected even more condensation because it was now the coldest spot in the room.

What worked better was opening windows hard and briefly. Ten minutes with two windows open on opposite sides of the flat, twice a day, swaps out most of the damp air without chilling the walls and furniture. We do it first thing in the morning and right after dinner, which is also when the kitchen has just added its own steam. Bastian wrote about the heating side of this in how we keep the flat warm without the bill spiking, and the short airing habit fits inside that plan without costing much heat.

I do still crack a window in the bathroom when the shower has been running, because that room has no extractor fan. That is a different problem from laundry, though, and closing it again after twenty minutes matters.

What we bought, and what we would skip

We spent $230 in total over two winters. Not all of it earned its keep.

One caution about compressor dehumidifiers: they lose a lot of their effect in rooms below about 15°C. If your flat is colder than that in winter, a desiccant model handles the cold better, though it uses noticeably more electricity. We run ours in the living room, in the same corner as the airer, for about nine hours on wash days, then empty the tank into the toilet in the morning.

We also put the dehumidifier on a timer to start at 11 p.m. when our electricity is cheaper. The clothes are mostly dry by breakfast, and I am not listening to it hum through dinner.

Small habits that kept the walls dry

Most of this costs nothing. It just took us a while to make it routine:

• Wash in the morning so the heaviest drying happens while the heating is on and we are awake to air the rooms.
• Shake every item hard before hanging. Creased bunches of fabric trap water and take hours longer.
• Leave a hand's width between items on the airer. Overloading it means the middle layer is still damp the next evening.
• Keep wardrobes a few centimeters off outside walls so air can move behind them. That gap is where our first mould patch grew.
• Wipe window condensation each morning with a squeegee and a cloth, and wring the cloth into the sink instead of leaving it to dry indoors.

Splitting the washing has helped too. Bastian does towels and bedding on Saturday mornings when the dehumidifier can run all day, and I do clothes midweek. We agreed on that during one of our weekly chore check-ins, mostly because we were both tired of a wet airer in the middle of the room every single evening.

I will be honest about one thing I cannot fix: our north-facing bedroom wall still gets cold enough to show a faint damp line in the worst week of January. Laundry habits brought it down from a black patch to a line we wipe once a week. A poorly insulated wall is a landlord conversation, and no airer placement solves that.

One thing to try this week

Buy a hygrometer, or borrow one, and put it in the room where your laundry dries. Read it the evening after a wash day and again the next morning. If it stays above 65 percent, change one thing, either the spin speed, the room, or two short airings a day, and read it again after your next load. You will know within a week which change matters in your flat. More of what we have learned about keeping a small place livable is in Our Home.