What does a ‘20 L/day’ rating mean in an air-conditioned room?
The short answer
It is the most water the unit can remove in 24 hours under the manufacturer's test conditions. Stadler Form states its rated performance applies from about 22 °C and 70% relative humidity. In a cooler, drier air-conditioned room, the same unit removes less. Use the rating to compare models, not to predict how many litres you will collect.
Why output drops in an air-conditioned room
Cool air holds less moisture than warm air, and AC already removes some of it. When there is less water in the air to begin with, a dehumidifier collects less, even when it runs all day. That is normal and does not mean the unit is underperforming.
A room can still feel damp at a lower reading than you might expect, especially near cold glass or AC vents, where condensation forms first.
The ratings side by side
| Model | Rated capacity | Rated room size | Noise | Filter |
|---|---|---|---|---|
| Theo | 10 L/day | Up to 40 m² / 100 m³ | 42 dB(A) | None |
| Albert | 20 L/day | Up to 70 m² / 175 m³ | 33–44 dB(A) | None |
| Lukas | 20 L/day | Up to 70 m² / 175 m³ | 38–52 dB(A) | Optional HEPA H11 |
| Lukas Pro | 50 L/day | Up to 175 m² / 435 m³ | 38–55 dB(A) | HEPA H11 included |
Manufacturer ratings from Stadler Form UAE, checked 20 October 2026. Stadler Form states rated performance from about 22 °C and 70% relative humidity.
How to compare models fairly
- Look at the room volume rating (m³), not just floor area. A high ceiling means more air to treat.
- Leave headroom. A unit working at the top of its rated range runs longer to reach the same level.
- Compare noise at the setting you will actually use, especially for bedrooms.
- Treat an open-plan space as one room only if air moves freely between the areas.
What a rating can't tell you
A capacity figure says nothing about leaks, closed doors between rooms or a damp wall. If moisture keeps coming back in one spot, find the source first. Our selector checks for these situations before it suggests a model.
Frequently asked questions
Is a 50 L/day dehumidifier better than a 20 L/day one?
Only if the space needs it. A 50 L/day unit suits large or very humid spaces. For a single bedroom, a 20 L/day unit is often enough and smaller.
Why does my dehumidifier collect less water in winter?
Cooler, drier air holds less moisture, so there is less to remove. Output falls below the rating, which is measured in warm, humid test air.