How do I Choose the Best Solar Water Heater?

Hillary Flynn

Solar water heaters can be money savers and are environmentally friendly, but the initial purchase can be expensive. When purchasing this type of heater, it is important to look at the different types of solar water heaters available to determine which type would work best in a specific home. This type of heater can save a household anywhere from 50 to 80 percent of the current fuel cost of water heating, so choosing the very best option will help maximize that savings.

Woman with a flower
Woman with a flower

The first thing to look at is geographic location. Though solar systems are available for all climates, different regions will benefit from different types of heaters. A solar water heater is either active or passive. An active water heater uses circulation pumps and controls and a passive heater doesn't. That means an active water heater requires electricity and a passive system does not. Passive solar water heaters are best used only in warm climates.

Active solar water heaters are either indirect or direct circulation systems. Direct circulation systems work in climates that rarely freeze, but colder climates will require an indirect circulation system. Both types use collectors to take the energy from the sun to heat the water. An indirect circulation systems uses a non-freezing heat transfer fluid that circulates through the collectors. This fluid collects heat then transfers it to the water used in the home. Direct systems circulate the water to be used through collectors.

Two types of passive solar hot water heating systems are available. The first is an integral collector-storage system in which the storage tank acts as the collector. These are generally painted black. The sun heats the water directly, then water pressure from a well or city water pushes the heated water to the faucets or another holding tank within the house. The second is a thermosyphon system in which the storage tank is mounted above the collector and gravity pushes the heated water through the tank, but these must be mounted on a roof and are therefore not appropriate for all homes.

So, when selecting a solar water heater, it should first be determined which type is appropriate for the climate in which it will be installed. Next, determine the amount of solar energy available. This will help determine the solar efficiency. The amount of hot water needed must also be noted. This determines the size and type of collector and storage tank. Finally, check prices and weigh all the other factors to determine the biggest savings and most efficient solar water heater for the location, size, and use of the home.

You might also Like

Readers Also Love

Discussion Comments


Is an active solar water heater also known as a high pressure water heater?

Secondly, I have a water tank at ground floor level and I am planning to install a solar water tank together with its collectors on the roof of my house. My house has only a ground floor. Do I need to buy a low pressure solar heater or a high pressure solar water heater?


Regarding the best technology (type of panel, vacuum tube versus flat plate, etc.), it depends on the application. According to research, flat plates are the best for residential and commercial solar water heating for up to 150 degrees F. An application where 180F is needed, vacuum tubes may be the solution.

Other things to consider are durability and where it's manufactured.


I am currently in the process of buying a solar water heaters for my home.

However I am still confused which solar technology should I decide to buy since there are various type such as vacuum tubes, coil, flat panels. Therefore I would appreciate if you provide me with any guidance on this new technology and even some useful, independent links especially for mediterranean climate.

thanks, Jonathan


@ Aplenty- You can expect solar water heater panels to work relatively well at heating your pool and extending your swimming season, even in an area where the sun isn't always shining. In an area with ideal sunshine you may be able to warm your pool about 10 degrees. In your climate, the temperature increase would probably be closer to 5 degrees. If you are handy, you can even install the system yourself, saving a few hundred dollars.

If you would like to warm your pool a little more, you can install a solar absorbent pool cover. They come in different thicknesses depending on your insulation needs. These covers can increase your pool temperature another five degrees or so as well as prevent water loss from evaporation. You can install these covers on an existing spool for your convenience.

Either of these options will probably be cheaper than installing an electric pool heater and it will save you money in the long-term. In addition, you will be doing the environment a favor.


Does anyone know how a pool solar water heater works? I would like to extend my pool into a three-season pool and I would like to know if this would be a viable option. I live in Northern California and I get quite a bit of sun, but there are cloudy and foggy days.


This is an excellent article. I am a sustainability student studying energy, technology, and materials science. I know a lot about thermal and photovoltaic energy systems used for power generation, but I do not know much about solar hot water heating methods. I have always wondered how exactly the solar panel water heaters work that I see all over Phoenix, but I do not know anyone who has one installed. This explanation was informative and to the point. Thanks wiseGEEK!

Post your comments
Forgot password?