Dehumidifier Calc

By floor area

What size dehumidifier for 2,000 sq ft

A 2,000 sq ft space needs somewhere between 28 and 74 pints per day depending on how wet it actually is. The condition matters more than the floor area, which is why one number cannot answer this.

By condition

ConditionWhat it looks like Pints / dayUnit size
Slightly damp50-60% RH, smells fine, no visible damp2830 pint
Moderately damp60-70% RH, musty after rain3850 pint
Very damp70-80% RH, damp patches on walls or joists5050 pint
Wet80-90% RH, condensation on ducts and pipes6270 pint
Extremely wet90%+ RH, standing water at times7490 pint
Slightly damp28 pints/day, 30 pint
Moderately damp38 pints/day, 50 pint
Very damp50 pints/day, 50 pint
Wet62 pints/day, 70 pint
Extremely wet74 pints/day, 90 pint
The same 2,000 sq ft at each moisture level, bar length by pints per day. Fixed additions for a sump pit or bare earth sit on top of every bar here.

Two common cases at 2,000 sq ft

Vented crawl space over bare earth, very damp. The ground and the outside air both feed moisture in, so the fixed additions do most of the damage: 61 pints per day, which puts you in the 70 pint class. Sealing the vents and laying a vapour barrier first will cut this more than buying a bigger unit will.

Basement with a sump pit, very damp. 54 pints per day, the 70 pint class. The pit is an open water surface, so it keeps giving off moisture even in a dry week.

See AlorAir crawl space and basement units

Why not just buy the biggest one

An oversized unit short cycles. It pulls the space down to the setpoint fast, shuts off, and the compressor never runs long enough to drain properly, so you get worse humidity control and more wear than a right sized unit running longer. Oversizing also costs more to run in a space that never needed it.

Check before you buy

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See AlorAir crawl space and basement units