Free dehumidifier sizing calculator
Dehumidifier Size Calculator: How Many Pints Per Day?
Answer four quick questions about the home and its moisture, and the calculator returns a planning capacity in pints per day, matched to the sizing classes in our whole-house dehumidifier guide.
Quick answer: What size dehumidifier do I need? For a 1,800 sq ft home reading around 62% indoor relative humidity with noticeable stickiness and an AC that cycles off early, the calculator lands at about 75 pints per day — the About 70–100 pints/day class this site's dehumidifier guide lists for 1,500–2,500 sq ft homes. Larger homes, higher readings, or persistent dampness move the class up.
What size dehumidifier do I need?
How this calculator works
The calculator starts from a planning load of about one pint per 35 sq ft, adds weight for dampness symptoms and how hard the AC already cycles, and rounds to whole pints. The result is then matched to the sizing classes in this site's dehumidifier guide — up to 1,500 sq ft, 1,500–2,500 sq ft, 2,500–3,500 sq ft, and over 3,500 sq ft — and a class never drops below its band's floor. A moisture load that outruns the table's 120-pint ceiling points to a load calculation or a staged approach instead of a bigger number.
Pinellas County context
Pinellas County homes pull in some of the most humid air in the country, and moisture problems here rarely come from one cause: ducts leaking attic air, mild weather that keeps the AC off, and tightly sealed envelopes that trap what is left. The dehumidifier guide on this site treats repeated readings above 60% relative humidity as clues — not a diagnosis — and that is exactly how this calculator treats them: as planning inputs, not a verdict.
Frequently asked questions
What size dehumidifier do I need for a 1,800 sq ft home in Florida?
At the calculator's defaults — 1,800 sq ft reading around 62% indoor relative humidity with noticeable stickiness and early AC cycling — the planning figure is about 75 pints per day, which sits in the About 70–100 pints/day class our dehumidifier guide lists for 1,500–2,500 sq ft homes. A tighter envelope with fewer symptoms can plan lower; persistent dampness or leaky ducts can push the same home toward the 100-pint ceiling.
Is a 70-pint dehumidifier big enough?
It can be — for smaller homes, or homes whose dampness is modest. The guide's sizing table plans About 70 pints/day for homes up to 1,500 sq ft and About 70–100 pints/day for 1,500–2,500 sq ft, so a 70-pint class is a planning fit at the low end of those bands. Symptoms matter as much as square footage: musty odors, condensation, or an AC that runs nearly constantly all argue for the upper end of a band.
What indoor humidity should I aim for in Florida?
This site's humidity guidance uses repeated readings above 60% relative humidity as the assessment clue, and notes many homes feel better closer to 30% to 50% when the home and system can hold it. Take readings where you notice the dampness, at a few times of day, before sizing anything around one number.
Doesn't my AC already remove humidity?
Yes — while the indoor coil is cold, cooling removes moisture as a byproduct. The guide's dividing line: when the system is functioning correctly but humidity stays high during mild rainy weather, shoulder seasons, or overnight, a separate dehumidifier becomes worth evaluating. Design airflow matters too — around 350 CFM per ton removes more moisture per cycle than 450, which is why our duct CFM calculator offers it as the humidity-control target.
Whole-house unit or portable dehumidifier?
A portable unit is honest and practical for one room, or for testing whether dehumidification helps at all. A ducted whole-house unit suits persistent moisture across multiple rooms once the HVAC and building moisture sources have been evaluated. This calculator sizes the whole-house case; the guide walks through drainage, noise, and placement differences.