Dehumidifier Sizing Calculator
Pints/litres per day for a damp space, AHAM-2019 style, from area and dampness class.
Post-2019 ratings test at 65 °F (not 80) — old '70-pint' units re-label as ~50. Size by the NEW numbers and drain by hose, not bucket.
Formula
Dehumidifier Sizing Calculator is a free dehumidifier size for HVAC designers, technicians and energy auditors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Dehumidifier Sizing Calculator
Pints/litres per day for a damp space, AHAM-2019 style, from area and dampness class. The calculation implements AHAM DH-1-2019 table fit: base 20–30 pints @500 ft² + 5–9 per extra 500 ft² (AHAM DH-1-2019; ENERGY STAR dehumidifier guide). Post-2019 ratings test at 65 °F (not 80) — old '70-pint' units re-label as ~50. Size by the NEW numbers and drain by hose, not bucket.
How to use Dehumidifier Sizing Calculator
- 1Enter Space area in m².
- 2Enter Dampness (1 damp (musty smell) · 2 very damp (visible spots) · 3 wet (seepage)).
- 3Read Capacity (AHAM 65°F/60%), Capacity instantly — no submit button needed.
- 4Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Dehumidifier Sizing Calculator?
- ✓Implements the standard formula — AHAM DH-1-2019 table fit: base 20–30 pints @500 ft² + 5–9 per extra 500 ft²
- ✓Reference cited on-page: AHAM DH-1-2019; ENERGY STAR dehumidifier guide
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Dehumidifier Sizing Calculator use?+
It computes AHAM DH-1-2019 table fit: base 20–30 pints @500 ft² + 5–9 per extra 500 ft², per AHAM DH-1-2019; ENERGY STAR dehumidifier guide. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Post-2019 ratings test at 65 °F (not 80) — old '70-pint' units re-label as ~50. Size by the NEW numbers and drain by hose, not bucket.
Is this based on ASHRAE methods?+
The calculations follow the standard ASHRAE/ISHRAE formulations cited under the result, simplified where industry practice does the same. For permit-grade design, confirm with the full code procedure.
Is the Dehumidifier Sizing Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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