Young Reddish Blonde Girl Enjoys The Swimming Pool

The heating effectiveness of a cover depends on type. A transparent bubble cover is the most effective, as it allows the largest amount of solar flux into the pool itself. Thermal bubble covers are lightweight UV stabilized floating covers designed to minimize heat loss on heated swimming pools. Typically they are only fitted in spring and fall (autumn) when the temperature difference between pool water and air temperature is greatest. They raise temperature of a pool by around 20 °Fahrenheit, or 11 °Celsius, after being on the pool for a week. Bubble covers are typically applied and removed by being rolled up on a device fitted to one side of the pool. Covers fall apart after 4 or 5 years due to sun exposure, overheating in the sun while off the pool, and chlorine attacking the plastic. Bubble covers should be removed during super chlorination.
A vinyl cover absorbs more sunlight directly, allowing temperature to rise faster, but ultimately prevents the pool from reaching as high a temperature as a clear cover. Vinyl covers consist of a heavier material and have a longer life expectancy than bubble covers. Insulated vinyl covers are also available with a thin layer of flexible insulation sandwiched between two layers of vinyl. These covers are mandatory (citation needed) to be fitted to all pools in areas of Australia that have experienced drought since 2006. This is an effort to conserve water, as much water evaporates and transpires.
An alternative to a continuous sheet of pool covering is multiple floating disks which are deployed and removed disk by disk. They cover most of the surface of the pool and offer evaporation reduction similar to continuous covers. Various types are available, for example opaque (for UV resistance and possible reduced algal growth), transparent (for esthetics), heavy and solid (for wind resistance), light and inflatable (for ease of handling).