If you’re in the market for a new solar water heater, you will need to do some research and shopping to find the right product for your needs. Of course, your choices are many. When evaluating your options, it is important to have a clear idea of what kind of system you are looking for. Before selecting a solar water heater, you’ll need consider your lifestyle, climate zone, budget, and environmental impact goals.

Here are four important questions to answer before shopping:

1) How much how water do you want to generate? Lifestyle has a major impact on how effective your domestic solar water heater will be. If you have a large family and a great demand for hot water, especially during the day, an active system with a larger collector will probably fit your family’s needs.

On the other hand if your household is only one or two people and activities like laundry are infrequent, a smaller “batch” or passive system might be better. A quick way to determine your expected household hot water use is to simply multiply occupants by 18 gallons. A family of four uses about 72 gallons of hot water a day for laundry, bathing, cleaning, and cooking. This number will help you gauge not only the collector you need, but also the reserve tank necessary for keeping your family in hot water.

2) Where do you live? Most systems are configured based upon expected output of hot water for a specific climate. In sunny, warmer areas like Florida, Arizona, and Southern California, you can generate a tremendous amount of hot water using a relatively small system. In colder regions a larger collector will be required, and an active system may be needed to satisfy the home’s hot water needs.

It is also important to understand if there is a potential freezing risk for your system. In colder areas you may have to select a “drainback” tank model, or a system that will automatically monitor the temperature to reduce the risk of a pipe bursting in your collector.

3) What is your budget? Solar heated domestic water does not have to be expensive. When compared to photovoltaic arrays, solar water heaters have a much faster return on investment and are much more affordable. For only a few hundred dollars you can build your own batch-style system--and even commercially manufactured systems for warmer climates can be very affordable.

Before shopping, be sure to get exact estimates from your plumbing contractor and check with local housing code officials to make sure you won’t have any hidden costs once installation begins.

4) How green do you want to go? If you are going to purchase a solar hot water heater, the benefits will be many, but a common goal is to reduce the overall need for carbon-based fuels like coal or natural gas. While the “greenest” and most economical option would be to simply alter your lifestyle so that you don’t use as much hot water (like taking “navy” showers, washing your cloths on cold water only and turning down the temperature on your current hot water heater) installing a solar water heater can make a significant positive impact on the environment.

To really go green, try to find systems that don’t require any additional energy to function. This can include choosing a simple batch heating system or passive system that uses thermodynamics to power the circulation process. Another way to avoid having to plug-in your system is to purchase a solar powered circulation pump. Once your new system is installed, altering your lifestyle to take advantage of the solar powered hot water is an excellent way to optimize your environmental impact. By using a majority of your hot water in the mid- to late afternoon you can help ensure that you will be getting the most from your new system.

Once you have determined your hot water needs, system style, size, and budget, you are ready to go shopping. Below are links to reviews of a few popular solar domestic water heaters on the market today.