The Copperheart is a passive "batch" type collector that holds 20-40 gallons of water (depending on the model) and is plumbed in-line before the water heater. Although it is usually used as a pre-heater the system can be configured to bypass the water heater and send solar hot water straight to the house. The thermal mass of the stored water provides some protection from freezing, but these systems are recommended only in climates where the overnight low does not fall below 27 degrees Fahrenheit. One advantage of the Copperheart is it has no moving parts, which means lower maintenance.

The Drainback system is a closed loop solar water heating system which uses water, rather than anti-freeze or oil as a heat exchange medium. The system must be plumbed so the collector and all piping slope back toward the storage tank and the drainback reservior tank so that when the system shuts off, all of the water drains from the collector and piping so that no water is left above the roof-line where it could freeze. An advantage of the drainback is the fact that the heat-exchange fluid drains from above the roof when the system shuts off providing protection from overheating as well as freezing.

Simple and effective, this system circulates non-toxic propylene glycol anti-freeze solution through the solar collector and then the heat is transferred to the water tank by means of an internal heat exchanger integrated within the storage tank. In addition to the heat exchanger the storage tank is equipped with its own electric heating element for back-up heating, or the system can be used to pre-heat for an existing gas water heater. Non-toxic propylene glycol provides 100% freeze protection. When properly maintained, systems can last over 30 years. Automatic Differential Thermostatic Controls make the system totally automated, and can be upgraded to include Internet connected Data Monitoring equipment if desired.