Active Vs. Passive Solar Power for Your Home

Harnessing the sun’s power has been a goal of humankind since ancient times. Cliff dwellers used overhangs to keep out the hot summer sun while allowing the winter sun’s rays to reach inside and heat the rocky floor and walls. The Romans covered south-facing windows with mica or glass to keep in the warmth generated by the sun. The more things change, the more they stay the same.

Choosing The Right Solar Power For Your Needs

It should be no surprise that climate affects your best options for solar power and how effective they will be for you. Israel, Spain and Australia have enacted national laws requiring solar usage in new construction. In these hotter countries, passive solar hot water heaters, for example, are commonplace. In fact, Israel has the highest per capita usage of solar hot water in the world, since their laws went into effect beginning in 1980.

In temperate and cool climates, some combination of active and passive systems are highly effective. Solar hot water heating remains the least expensive and simplest solar enhancement the average consumer can implement, but by no means the only one.

Passive vs. Active Solar

What exactly is the difference between active and passive solar?

• Passive solar energy systems function most efficiently through collection and convection, (think “hot air rises”).
• Active solar energy systems generate and store electricity in photovoltaic cells that is converted from DC (direct current) to AC (alternating current) for later use.

Typical Uses of Active Solar

• The most common types of active solar construction for consumers are:
• Roof-top solar collectors
• Swimming pool heaters
• Solar water heaters
• Whole-house solar heating systems.

Other uses for the consumer include outdoor lighting, such as in the garden or along a walkway leading to your home, cordless and cell phone recharging when away from electricity for extended periods, electric gate openers, as well as recreational vehicle and boat battery charging.

Typical Uses of Passive Solar

Three types of solar gain come from passive solar construction:

• Direct Gain
• Indirect Gain
• Isolated Gain

Examples of direct gain would be heat entering a home through south-facing windows, as well as solar “blankets” for heating pools.

Indirect gain is the process of direct sunlight on dark-colored, massive stone or liquid-filled containers, sometimes called Trombe walls where heat is stored during daylight hours and released at night into connecting spaces.

The most common example of isolated gain would be sun spaces, such as a greenhouse addition or even a so-called four seasons room that releases daytime heat into the rest of the home or vents it away at the top of the structure.

Regardless of whether you choose to implement passive or active solar energy enhancements to an existing home or a new construction, research and planning are essential. With government tax breaks for solar construction and renovation, combined with rising energy prices, even financing your energy improvements can be a viable solution. The higher energy prices climb, the faster you recoup your upfront investment in solar.

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