Indoor Pool Ventilation and Dehumidification Calculator

Estimate evaporation, outdoor and recirculated airflow, dehumidifier capacity, supply-air heating and glazing condensation risk. Multiple pools, spas or water zones can be evaluated independently.

1. Room and indoor air

Room volume

m³

Air temperature

°C

Usually 1 to 2°C above the pool water.

Winter relative humidity

Summer relative humidity

Swimmers at peak use

people

Spectators

people

Wet deck area

m²

Occupied hours per day

2. Water zones

Evaporation is calculated independently for each zone from area, water temperature and ASHRAE activity factor.

3. Outdoor design air

Barometric pressure

kPa

Winter temperature

°C

Winter relative humidity

Summer temperature

°C

Summer relative humidity

4. Air system and envelope

Air speed over water

m/s

ASHRAE recommends no more than 0.15 m/s.

Recirculation air changes

ACH

Sensible heat recovery

Capacity allowance

Exhaust above outdoor supply

Exterior glazing area

m²

Glazing U-value

W/m²·K

Detailed calculation record

Methods and design references

ASHRAE Handbook — HVAC Applications, Chapter 6, Indoor Swimming Pools — evaporation, activity factors, air delivery and condensation control.
SP 310.1325800.2017, Swimming Pools Design Rules — the outdoor-air minimum used by this calculator.
ABOK indoor pool design example — a Russian calculation example based on ABOK Recommendation 7.5-2020.

This calculator is a preliminary engineering estimate. It does not replace building heat-loss and heat-gain calculations, duct pressure calculations, envelope analysis, part-load modelling or final equipment selection from certified manufacturer data.