Regulating a swimming pool’s temperature can greatly contribute to its operating costs. One method that has been rated as "the most cost-effective” by the Department of Energy (DOE) in the united states, is solar pool heating. Although its capital cost may be competitive with both heat pump and gas pool heaters, but it has been proven that it has a very low annual operating cost.

A swimming pool solar heater usually consist of four (4) main components:

• A circulating pump
• A filter
• A solar collector 
• A flow control valve

Water from the pool is pumped through the filter then through the solar collectors, where by it is heated and returned to the pool. The system can be used to circulate water through the collectors are night for cooler temperatures. 

When the system is equipped with temperature sensors and automatic control valve, filtered water is automatically diverted through the collector or allowed to bypass it for a constant pool temperature.

Most domestic water solar heaters are installed per apartment or on detached houses. However, larger solar thermal systems are gradually being used more in apartment buildings, hotels and public buildings. Many of Europe’s establishments have become equipped with central solar water heaters. 

Central solar water heaters use one large solar collector common to all units, apartments, or facilities. This solar collector heats up a closed loop of water (or Heat Transfer fluid) that equally enters each unit’s separate heat exchanger. The heat exchanger heats water separately in each apartment, ensuring that all the apartments or units are receiving the same heating capacity.

Centralizing the system makes it more cost-effective and efficient, as the whole building now uses common solar panels, one pumping station, and is connected to one closed loop network (less pipework and control).

This system can work in parallel with conventional electric water heaters inside the apartments if hot water demand exceeds that of the system’s supply. Water circulates between the heat exchanger and the electric water heater inside the apartment to stay at the desired temperature.