Work out condensate drain sizing instantly with clear inputs, formula shown and shareable results.
A cooling coil condenses roughly 1.5 to 3 pints of water per ton per hour depending on how humid the entering air is. Eight pints make a gallon, so daily volume follows from run hours. Drain diameter is set by code band rather than flow: three-quarter inch up to 20 tons, one inch beyond that.
Condensate volume
gal/day = tons x pints per ton-hour x run hours / 8
gal/day = tons x pints per ton-hour x run hours / 8. A cooling coil condenses roughly 1.5 to 3 pints of water per ton per hour depending on how humid the entering air is.
Without a trap the drain pan connects the negative-pressure air stream to the drainage system, so the unit pulls sewer gas in and holds condensate in the pan instead of letting it flow.
This calculator takes 3 inputs: Cooling capacity, Condensate rate, Run hours per day. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.