Indoor Pool Dehumidifier Calculator

Use this calculator to get an estimated dehumidifier capacity (litres per day) for your indoor swimming pool.

Just enter:

• Your pool surface size – length and width of the water
• The pool water temperature
• The room air temperature
• Your target relative humidity (most indoor pools run around 50–60% RH)
• The pool type / activity level – quiet private pool, busy hotel pool, spa, etc.

Hit Calculate and the tool will give you:

• An estimated evaporation rate in kg/hr
• An estimated moisture load in litres per day
• Because 1 kg of water is roughly 1 litre, this gives a good idea of the size of dehumidifier you should be looking at for your pool room.

For most indoor pools, the aim is to keep the room at around 50–60% relative humidity, with the air temperature usually 1–2 °C warmer than the pool water so swimmers feel comfortable getting out and you avoid heavy condensation.

Important: this calculator is a guide only. It’s not a full psychrometric design and doesn’t replace a detailed assessment of the building, glazing, ventilation and ductwork.