Active solar water heaters

Do you know the difference between active solar water heaters and passive solar heaters?

While passive heaters require the sun as their only energy source, active solar water heaters require electric pumps, controllers, and other such equipment.

Active systems can further be divided into direct and indirect systems. Direct systems directly heat the water in the collectors while an indirect system heats a different fluid (e.g. freon or distilled water) and the heat from this fluid is then transferred to the household water.

Why would anyone want an indirect active solar water heater system? Even though it is less efficient, it requires less maintenance. The same is true of passive solar heaters compared to active ones – Yes, they are not as efficient, but they have no moving parts and are therefore much easier to maintain and much less likely to break down (also, passive systems are generally less expensive).