Dehumidifier sizing calculator
Work out the pints-per-day capacity your space actually needs.
Dehumidifier capacity is a calculation, not a preference. Enter your space and this works out the pints-per-day capacity you need, using the sizing basis published by the Association of Home Appliance Manufacturers and the current US Department of Energy test procedure.
Questions about this tool
Why is this smaller than older guides suggest?
The US Department of Energy changed the dehumidifier test procedure in 2019, and capacity is now measured at 65F rather than 80F. A machine once sold as a 50-pint unit is typically labelled around 32 pints today. Guides written before 2019, and the many reviews that copy them, recommend numbers that no longer match what is printed on the box.
Does oversizing hurt?
Rarely, beyond cost, bulk and noise. An oversized dehumidifier reaches the target humidity sooner and then cycles off. Undersizing is the expensive mistake: the unit runs continuously, never reaches target, and wears out sooner for it.
What if the space is cold?
Capacity and low-temperature operation are different specifications. A standard compressor dehumidifier loses capacity as air cools and can ice up below roughly 65F. Crawl spaces, garages and unheated basements need a unit specified to run cold, whatever its pint rating.