Solar Hot Water

Water heating through solar panels is the most common, efficient, and the oldest way of using solar power in the world.  There are many more solar hot water systems in North America than there are solar power (photovoltaic) systems.  This is due to their lower cost, easier maintenance, and simpler designs.

Solar water heating systems come in two basic varieties: active and passive.  Passive systems are best suited for southern climates where the temperature rarely reaches freezing and if it does, it doesn’t do so for long.  These systems are very low maintenance, but are also less efficient than their active counterparts.

Active solar water heaters use pumps and controllers to move liquids through the heating system.  These are the most common type of commercial solar water heating systems for residential and small site use.  Active systems come in two varieties: direct and indirect circulation systems.

Direct circulation systems send the actual water to be heated into the solar panel (or solar collector).  The water is heated and then sent to a storage tank or into the live water line for use.  These are simpler and more common systems, especially in areas that do not have prolonged freezing temperatures.

Indirect systems send a non-freezing liquid (usually water with anti-freeze or a thin gel) through the solar collector and then pipe that through a water storage tank or other piping to heat water indirectly through heat transfer.  These systems are more common in more extreme climates where freezing temperatures can be had for days on end, rather than just overnight.

Whatever the system, solar hot water is much more efficient, greener, and lower cost (over time) than are conventional heating systems such as gas or electric water heaters.  Many complete solar water heating systems use gas or electric heaters as a backup or are used to supplement an already-existing conventional system.  No matter how it’s used, solar hot water is always an energy saver.