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How do I Choose the Best Solar Water Heater?

Selecting the best solar water heater involves considering efficiency, capacity, climate compatibility, and cost. Look for certified models with strong warranties and positive reviews. Assess your household's hot water needs and local sunshine patterns. Remember, a well-informed choice leads to long-term savings and eco-friendly living. What factors will influence your decision the most? Continue reading to make an informed choice.
Hillary Flynn
Hillary Flynn
Hillary Flynn
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.

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.

Woman with a flower
Woman with a flower

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.

Frequently Asked Questions

What factors should I consider when choosing a solar water heater?

When selecting a solar water heater, consider the climate, as direct systems are ideal for warm regions while indirect systems suit freezing conditions. Evaluate the system's efficiency, typically measured by the Solar Energy Factor (SEF), and look for a higher SEF for better performance. Also, assess the capacity needed based on household size and water usage patterns. Lastly, check for certifications like the Solar Rating and Certification Corporation (SRCC) to ensure quality and reliability.

How do I determine the right size for my solar water heater?

To determine the right size for your solar water heater, calculate your household's daily hot water usage. An average person uses about 20-30 gallons per day according to the U.S. Department of Energy. Multiply this by the number of people in your home to estimate your total daily hot water needs. Then, choose a system with a tank size and collector area that can meet this demand, even during the shortest days of the year.

Are solar water heaters cost-effective compared to traditional water heaters?

Solar water heaters are generally more cost-effective in the long run compared to traditional water heaters. They have higher upfront costs but can significantly reduce monthly energy bills. According to the U.S. Department of Energy, solar water heaters can decrease your water heating bills by 50% to 80%. Additionally, they have longer lifespans and may qualify for tax credits and incentives, enhancing their cost-effectiveness.

Can a solar water heater work in a cloudy climate?

Yes, solar water heaters can work in cloudy climates. Modern solar thermal systems are designed to absorb diffuse sunlight and can still generate hot water during overcast conditions. However, their efficiency might be reduced, so it's important to have a correctly sized system and possibly a backup heating source. In some cases, evacuated tube collectors are recommended for their superior performance in cloudy conditions.

What maintenance is required for a solar water heater?

Solar water heaters require minimal maintenance, but regular checks are important to ensure optimal performance. Annual inspections by a qualified technician are recommended to check the system's components, such as the pumps, valves, and solar collector cleanliness. Also, the pH and antifreeze levels in the heat transfer fluid should be checked in indirect systems, as stated by the National Renewable Energy Laboratory.

How does the efficiency of a solar water heater compare to electric or gas heaters?

The efficiency of a solar water heater is generally higher than that of electric or gas heaters when considering energy conversion. Solar water heaters convert up to 80% of solar radiation into heat energy, while electric and gas heaters have efficiency rates ranging from 20% to 95%, depending on the model and type. This high efficiency translates to lower operational costs and reduced carbon footprint for solar water heaters.

Hillary Flynn
Hillary Flynn

Joining the TheSolarPanelGuide team has helped to satisfy Hillary’s insatiable curiosity for knowledge. She also manages an electronic publishing business that allows her to develop her skills in technical writing, graphic design, and business development. Hillary has a passion for satirical writing and enjoys traveling, especially to places of historical importance.

Learn more...
Hillary Flynn
Hillary Flynn

Joining the TheSolarPanelGuide team has helped to satisfy Hillary’s insatiable curiosity for knowledge. She also manages an electronic publishing business that allows her to develop her skills in technical writing, graphic design, and business development. Hillary has a passion for satirical writing and enjoys traveling, especially to places of historical importance.

Learn more...

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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!

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