For dehumidifiers, the most important number is on the box: the number of liters the device removes from the air per day. However, that figure doesn't mean much without context — a compact model in a bedroom does more useful work than a large unit running in a drafty garage. This article translates capacity into your specific situation: which room, how humid, and how quiet it needs to be.
First: how humid is it at your place?
Before choosing based on capacity, measure it once. A hygrometer costing a few euros tells you more than any product sheet: 40 to 60% humidity is healthy and comfortable. If you are between 60 and 70%, there is a light to moderate moisture load — think fogged windows or a damp closet smell. Above 70%, it is structurally too wet, and you will see visible effects (mold spots, musty odors) or have a clear source like laundry drying indoors. The higher the percentage and the larger the room, the more capacity you need.
Capacity selection by situation
| Situation | Indication |
|---|---|
| Bedroom, bathroom, walk-in closet, caravan | Compact model — quiet, space-saving, suitable for continuous use |
| Living room or open-plan living area | Mid-range — larger space, more air to process |
| Laundry room where laundry dries indoors | Higher capacity model — this is the heaviest moisture source in the house |
| Basement, garage, or shed | Higher capacity model; check the device's minimum operating temperature |
The practical rule of thumb that applies everywhere: a device that is too small for the room will run continuously without reaching the target level; a properly sized device works for shorter periods, successfully lowers the humidity, and lasts longer. If you are doubting between two sizes, choose the larger one — the excess costs you some storage space at most, while being too small costs you the result.
Two technologies: compressor or desiccant
There are two ways to remove moisture from the air, and the difference lies in the temperature at which they work.
Compressor models cool the air so moisture condenses — the same technique as a refrigerator. They are energy-efficient and effective in normal, heated living spaces. At low temperatures (such as an unheated garage in winter), their efficiency decreases.
Desiccant (adsorption) models work with a moisture-absorbing material and perform well even at low temperatures. This makes them the logical choice for basements, sheds, garages, and holiday homes that remain cold in winter. They are generally lighter and more compact but consume slightly more power for the same output.
In short: heated rooms → compressor; cold rooms → desiccant.
What else you want to know before choosing
- ✔ Noise level — for a bedroom, this is more important than capacity; a device you turn off at night won't dehumidify anything
- ✔ Water tank size — a small tank means more frequent emptying; check if the model stops automatically when full (this should be standard)
- ✔ Continuous drainage — some models can drain directly into a drain via a hose: ideal in a basement or laundry room, so you never have to empty it
- ✔ Hygrostat or automatic mode — the device switches off automatically at the set percentage and turns back on when it rises: more energy-efficient and quieter than running continuously
- ✔ Portability — handle and weight matter if you plan to use it alternately in the bedroom and laundry room
How to get the most out of your dehumidifier
Three habits will practically double the effect. Keep doors and windows closed while dehumidifying — otherwise, the device will try to dry the entire house (or the outside air). Place it in the open, with space around it for air circulation, preferably centrally in the room or close to the moisture source. And most importantly: tackle the source first. A dehumidifier next to a rack of wet laundry is like trying to dry off while standing in the shower; the complete approach — source, ventilation, and only then dehumidifying — is covered in our article "Moisture in the house? How to prevent mold".
Frequently asked questions
How many liters per day do I need?
That depends on the size of the room and how humid it is. For a bedroom or bathroom, a compact model is sufficient; for a living room, laundry room, or basement, choose a larger capacity. Measure first with a hygrometer: the further above 60% you are, the more capacity is required.
Can a dehumidifier stay on continuously?
Yes. Models with a hygrostat switch off automatically once the set percentage is reached and turn back on when it rises — this is more efficient than manual switching. A full water tank stops the device automatically; with continuous drainage via a hose, you don't even have to keep track of that.
Does a dehumidifier work in a cold garage?
A compressor model loses efficiency at low temperatures; for unheated spaces like basements, garages, and sheds, a desiccant model is the better choice because it keeps working in the cold. Always check the specified minimum operating temperature of the model.
Does a dehumidifier heat up the room?
A little: the device consumes electricity and releases heat, which causes the room to warm up slightly. This is usually a pleasant side effect — moreover, drier air feels warmer at the same temperature, often allowing you to set the heating a little lower.
Do you know what size you need? View the dehumidifiers from Strex — quiet enough for the bedroom, with automatic shut-off when the tank is full. Find more for a healthy home under household appliances.
