These systems have two main advantages:

• They are relatively very simple, cheap and easy to install.
• The lack of complex parts makes them easy to maintain.

It's also important to consider the disadvantages:

• Direct systems cannot be used in hard water areas, unless a water softener is installed before the collector.
• They cannot be used where freezes occur, unless an indirect system is installed and the storage tank is in a heated area of the building.
• The storage tank must be installed above the collector array, which is unsuitable in many residential settings.