Heating of Swimming Pools

“Why heat a swimming pool?”

Is a question those who enjoy swimming in the sea may ask but there are several reasons as to why the heating of swimming pools may be applicable whether said pool is an indoor or an outdoor pool.

Firstly many people do not live close to the sea, a lake, a pond deep enough and big enough for swimming in or near to a Public swimming pool therefore they decide to have their own swimming pool.
Said pool may either be of a permanent or temporary structure and may be installed for private or commercial purposes which, in the case of the latter, could be for diving or swimming classes for example.
It may be that the swimming pool is for therapeutic / health reasons or just for fun purposes with the users of said pool not being comfortable necessarily in cold water with them wishing to have warmer water in which to swim.

Another aspect to consider when looking at heating a pool is to make swimming all year round more appealing for those who do not like swimming in chilly or cold water.
The heating of swimming pools can be done in several ways some of which require electricity or another power source other than the sun.
Swimming pool heating costs can be significantly reduced by using a pool cover with said covers coming in different forms.
Use of a pool cover also can help reduce the amount of chemicals (chlorine, etc.) required by the pool.

Outdoor pools gain heat from the sun, absorbing 75% to 85% of the solar energy striking the pool surface.
If a cover is on the pool during a sunny / hot day it generally decreases the total amount of solar heat absorbed by the pool but the cover does eliminate heat loss due to evaporation and reduces heat loss at night through its insulating properties with most swimming pool heat loss being through evaporation.

The heating effectiveness of a cover also depends on the type of the cover.
A bubble type cover (referred to as a “Solar Blanket”) is generally 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 swimming pools.

Increasing the overall temperature of a pool is dependent on many factors such as:-
a) number of solar panels installed.
b) size of pool.
c) whether the pool has been fibreglassed, marbalited or painted, with the fibreglass option being the best as far as keeping the pool warmer for longer.
d) whether a pool cover has been installed.
e) whether it is a sunny or hot day. If it is overcast this will also have a negative affect on the temperature of the pool water.
But typically putting in solar panels can increase the water temperature by on average 5 degrees celcius.

Bubble covers are typically applied and removed by being rolled up on to a “roll-up station” fitted at one end of the pool.
Bubble covers should be removed during super chlorination.
A vinyl / metal cover absorbs more sunlight directly, allowing the temperature to rise faster, but ultimately prevents the pool from reaching as high a temperature as a bubble cover.
Vinyl / metal covers consist of a heavier material and have a longer life expectancy than bubble covers.
Insulated vinyl / metal covers are also available with a thin layer of flexible insulation sandwiched between two layers of vinyl (in the case of a vinyl cover).

Solar panels also heat the pool provided they are optimally positioned and can be adjusted (switched “On” & “Off”) as required but obviously only work with direct sunlight.
Another form of pool heating is pool “Heating Pumps” which can be thermostatically controlled and require some form of power be it electricity / diesel or gas to make them work with it being noted that some form of cover to retain the heat in the pool should be considered for full benefit.