Drying in a room with no windows

Short answer: Without air exchange the room is saturated with moisture in under an hour, and after that drying almost stops. The solution is either a dehumidifier or a fan. With one of them even a small windowless room can work well for drying.

Saturated air does not dry

Air can only hold a certain amount of water, and once that limit is reached nothing more evaporates from the clothes. The fabric stays damp even though the room is warm. That is why bamboo sweatpants for women dry slowly in a closed bathroom, as the air around them is already full of water.

The dehumidifier removes the water

A dehumidifier draws air in, condenses the moisture into water in a tank and sends dry air back out. That lets evaporation from the clothes continue all the way. It halves the drying time for everything, including a bamboo bra, where the thicker parts at the edges otherwise hold moisture the longest.

The fan moves the air

Even without a window it helps to keep the air moving, so the saturated air right at the fabric is replaced by slightly drier air from the rest of the room. An ordinary fan pointed at the rack makes a clear difference. Try it with the most popular pieces from Copenhagen Bamboo when laundry has to dry without fresh air.

Why moisture in the room is a problem

It is not only the clothes that suffer when moisture lingers. Water that cannot escape settles on cold walls, in grout and behind furniture. Over time it can create a stale smell that also gets into your clothing. So removing moisture from the room matters just as much as removing it from the fabric.

Use the extractor fan

Many windowless bathrooms have an extractor fan in the ceiling. It is designed for exactly this job and can remove damp air if it runs for the whole drying time. Leave the door slightly open so fresh air can come in from below. Together that gives some air exchange, even when the room has no opening to the outside.

Give the clothes space

Hang the laundry well spaced, so air can get between the individual items. Clothes hung close together form pockets of damp air that dry slowly. Shake each item before hanging it and turn thick pieces partway through. The more surface exposed to the air, the faster it goes, even in a small room.

Spin thoroughly

The less water in the clothes to begin with, the less has to evaporate into the room. An extra spin in the washing machine is a simple way to make drying easier. Choose the highest speed the clothes can take, and remove the load soon after the cycle ends so it does not sit crumpled in the drum.

Check that everything is fully dry

In a windowless room clothes can feel dry on the surface while seams and waistbands are still damp. Feel the thickest spots before folding. Moisture shut inside a wardrobe spreads to the rest of the pile and leaves a musty smell that can be hard to get rid of again.

Frequently asked questions

How long does it take without help

Two to three days in a small closed room. With a dehumidifier or a fan it goes much faster, because the air can keep taking up water.

What does a dehumidifier cost to run

Around one Danish krone per hour at a normal electricity price. The amount depends on the appliance and your tariff, so check the actual consumption.

Is an extractor fan enough

In a bathroom often yes, if it runs for the whole drying time. Leave the door slightly open so fresh air comes in while the damp air is drawn out.