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Dehumidifier Size Calculator
Enter your room size and moisture conditions to get a practical starting recommendation for a 10L, 12L or 20L dehumidifier, plus the most suitable type for the room.
Your room
This is a practical buying guide, not an engineering calculation. Severe damp, leaks or building defects should be investigated separately.
Enter your room details
Your recommended capacity and dehumidifier type will appear here.
How this calculator works
For a normally heated UK room, smaller spaces with lighter moisture usually suit a 10–12L compressor dehumidifier. Larger rooms, heavier condensation or frequent indoor laundry can justify stepping up to 20L. In colder or unheated spaces, a desiccant model can be more effective even when its headline litre rating is lower.
Read our 10L vs 12L guide, 12L vs 20L comparison, and compressor vs desiccant guide.