Solar energy is the renewable resource that is most available to the most people. Unlike wind energy, which is found high above homes and business, and water power, which is relatively rare, most homes have at least some access to sunshine. Finding out how much — your site’s solar resource — is an important first step. Many homes have reasonable access to sunshine on the property, and can tap this abundant, free resource in more ways than one.

 Direct use of sunshine through passive solar design, solar cooking, solar drying, and the like requires few or no moving parts and can  be very cost effective in the right situation. Beyond these options, heating water and making electricity are the two most common ways to use the sun’s energy.

 Solar hot water systems use sunshine to heat water for domestic use, or sometimes for home heating (though passive solar design is a better place to start if home heating is your primary goal). In most places, 50-75 percent or more of the domestic water can be heated with a solar hot water system, avoiding what is often the second largest energy cost in a home. These systems use collectors that circulate water or anti-freeze to collect the sun’s heat, and can be passive (using natural movement of heat) or active (using pumps, sensors, and electronics).

 Solar-electric systems are a completely different technology that uses the light from the sun (and actually work better when it’s cooler) to make electricity. These systems can be used for direct loads (such as water pumping or ventilation), in off-grid situations, or on the utility grid, with or without batteries. Solar-electric (photovoltaic or “PV”) modules are ultra-reliable, with no moving parts—except the electrons—typically boasting 20-25 year warranties on energy production. This amazing technology combines two qualities not found in many other things we buy—longevity and productivity.