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Active vs. Passive Solar Hot Water Heaters: What’s the Difference?


Using a solar hot water heater can help save you money, save energy, and decrease your carbon footprint. However, there are choices to be made, as there are some options where solar water heaters are concerned. The first item to determine for any homeowner who wants to install solar water heating is choosing an active solar hot water heater or a passive one. This doesn’t mean you’ll have a water heater that moves around versus one that doesn’t; rather, passive vs. active describes the way the unit provides hot water to your home. Let’s take a closer look.

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The main difference between active and passive solar hot water heaters is that active systems use mechanics, such as pumps, to move liquid through the system; passive systems rely on gravity. Active systems may also use environmentally-friendly anti-freeze to transfer heat to the water, something a passive system does not do, and active systems need electricity to operate, whereas passive systems do not.

Examples of Systems

An example of a passive hot water heater is a simple solar collector. In a passive solar collector, water is heated in tubes that are fully exposed to the sun’s rays; when hot water is needed, a latch or flap opens, and the hot water runs down piping to an outlet. In an active solar collector, the scenario is different.  The hot water or anti-freeze is heated in the collector and pumps do one of two things: the hot water is moved into a storage tank via pumps for usage, or the anti-freeze is pumped into a coil in a storage tank where its heat is transferred to the waiting cool water.

Which Is for Me?

Choosing a specific type of solar hot water heater is something that should be done with a trained professional; this will ensure that you choose and install the right solar hot water heater for your home in New City, NY. The trained solar experts at Design Air Inc., can help you with this decision, so give us a call today!