Dehumidifier capacity in litres per day for a damp room, flat or basement.
How this works
Based on the AHAM sizing chart: a 46 m² (500 sq ft) space needs about 4.7 L a day if moderately damp, 5.7 L if very damp, 6.6 L if wet and 7.6 L if extremely wet, rising about 2 to 3.3 L for each extra 46 m². Box ratings are measured at 30°C and 80% RH, so we double the real need.
Questions people ask
How do I use the Dehumidifier Size tool?
Fill in the fields, starting with “Room length”, “Room width” and “How damp is it”, and change any other options that match your home. The answer, a drawing and practical tips update as you type, and the Copy link button saves your numbers in a link you can share.
Is the Dehumidifier Size tool free?
Yes. The Dehumidifier Size tool is free, with no sign-up, and works on phones, tablets and computers. The results are estimates to help you plan, so check with a qualified professional before structural, electrical, gas or plumbing work.