The choice of heating is first influenced by the location of our pool, whether it is indoor or outdoor. In the first case the operating conditions are quite stable and predictable, in the second a number of unpredictable factors affect the water temperature. Keeping the water in the pool between 22 and 28 degrees, depending on your preferences, will allow you to derive maximum pleasure from swimming. Renewable energy can be used for heating: solar collectors and pool heat pumps, this is certainly a good solution, but may not be sufficient. The most commonly installed in indoor pools are pool heat exchangers that work with central heating furnaces or electric water heaters. A well-chosen and well-thought-out pool water heater will not only improve comfort but also have a positive impact on maintenance costs. It is also worth remembering the pool cover, which will greatly reduce heat loss or, in the case of solar films, even increase it.