Pool Evaporation Calculator

This calculator estimates water evaporation from your pool based on environmental conditions including temperature, humidity, and wind speed.

Evaporation Formula:

Evaporation Rate = K x (Pw - Pa) x (1 + 0.1 x W)

Where K = constant (0.024), Pw = water vapor pressure, Pa = air vapor pressure, W = wind speed

Factors Affecting Evaporation:

• • Temperature Difference: Higher water temp vs air temp increases evaporation
• • Humidity: Lower humidity increases evaporation rate
• • Wind Speed: Higher wind speeds accelerate evaporation
• • Surface Area: Larger pools lose more water
• • Sunlight: Direct sun exposure increases water temperature

Typical Evaporation Rates:

• • Average conditions: 0.25" - 0.5" per day
• • Hot, dry climate: 0.5" - 1.0" per day
• • Humid conditions: 0.1" - 0.25" per day
• • Windy conditions: +50% increase over still air

Reducing Evaporation:

• • Pool Covers: Reduce evaporation by 90-95%
• • Windbreaks: Trees, fences reduce wind effect
• • Lower Temperature: Keep pool 2-3°F cooler
• • Shade Structures: Reduce direct sunlight
• • Chemical Covers: Liquid evaporation inhibitors

Environmental Impact:

• • Average pool loses 1,000-2,000 gallons per month
• • Hot climates can lose 3,000+ gallons monthly
• • Pool covers save water and reduce chemical loss
• • Covers also reduce heating costs by 50-70%

When to Check Evaporation:

• • Daily during hot, dry weather
• • Weekly in moderate conditions
• • More frequently if water level drops rapidly
• • Consider leak testing if loss exceeds calculations