UK home moisture help
Dehumidifier size calculator
Estimate whether a small, medium or larger dehumidifier is likely to suit your room, damp level and temperature.
Tool
Match the dehumidifier size to your room and damp level
Too small and it runs constantly without results. Too large and energy costs rise unnecessarily. Our calculator helps you size up correctly.
Dehumidifier size calculator
How to use the result
The calculator gives a practical starting point, not a surveyor's specification. For bedrooms and small offices, compact 10L to 12L units may be enough. For living rooms, laundry drying or persistent moisture, 20L units are often more practical. Cold spaces may favour desiccant models, while heated rooms often suit compressor models.
If you see staining, crumbling plaster, tide marks or water ingress, investigate the building issue rather than relying only on a dehumidifier.