Action Air Conditioning & Refrigeration  ·  Field Tool  ·  Clearwater, Florida

How much water
does a ton actually remove?

A ton is 12,000 Btu/h of total capacity. Only part of it removes moisture, and the split changes with the air you feed the coil. Set the conditions below and the arithmetic follows.

Sensible / latent split at the operating condition

Read this off the manufacturer's expanded performance table at the wet bulb you actually run — not off the nameplate. Catalogue ratings are taken at 80 °F / 67 °F wet bulb. A Florida house at 75 °F and 50% RH presents about 63 °F wet bulb, which pushes the split toward 80/20 or worse.

Airflow

Lower airflow means a colder coil and more moisture removed, at a small energy cost. Below about 325 you are into freeze territory once the filter loads.

Sensible — cools the air27,000
Latent — removes water9,000
Drawn to scale — Btu/h at the stated condition
Total capacity
36,000
Btu/h nominal
Moisture removed
196
pints per day, running
Air across the coil
1,050
CFM total
Temperature drop
23.8
°F, dry bulb across coil
Moisture wrung out
12.6
grains per pound, per pass
Latent per ton
65
pints/day per ton
Check

Adjust the settings above.

Ductwork these numbers require

Smallest fully-extended flexible duct clearing both a velocity limit and a friction limit — return 700 FPM / 0.05 in.w.g. per 100 ft, supply trunk 900 FPM / 0.08 — per ACCA Manual D Table 7. Return is not sized to the same friction target as supply.

Return, free area
216
square inches
Return, round
17″
or two smaller
Supply trunk, free area
168
square inches
Supply trunk, round
15″
at 900 FPM

Per-ton reference

The constants worth committing to memory. Your selection is highlighted.

SplitSensible/tonLatent/tonPints/day/ton ΔT at 350Grains at 350