Holds a Master’s degree in Engineering and is keen on her own home’s climate. Sometimes we think that Carolina owns every single product she writes about – that’s how profound and insightful her reviews always are.
For 8 years, Richard had been working as an HVAC specialist and AC unit installer since his student years. Now, he’s our main consultant on every technical aspect that may arise during our tests and research.
Last updated: December 11, 2020
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Having sufficient levels of hot water in the house is something a lot of people miss out on by purchasing the wrong device. It isn’t easy to find the best solar water heater, and we understand how people can find themselves in such a predicament. However, to prevent more people from experiencing the same thing, we have taken it upon ourselves to guide you through the buying process.
The ten devices below are deserving of their placement on the list, and we found this out by reviewing their features and attributes. Among these features is the capacity of the heater. After all, different capacities cater to different size households. The size of the device as a whole and the number of heating tubes is also crucial. Remember, you have to account for the installation space as well. Also, the type of heater helps determine output and heating results. With these features accounted for, we have been able to adequately rank all the products below so you can find out which is the best solar water heater for you.
Our first recommended purchase is the Duda Solar 200 Liter Water Heater. Users, of course, would like a system that can serve all the needs of the family, and this product delivers. As you can see in the capacity of the system, it can provide enough preheated water for showers, washing dishes, and more.
It comes with a stainless steel water tank that is bound to last a long time. Given that this is an active indirect system, the tank will likely find a permanent position indoors. Users will love this as when winter comes, the tank will feature less heat loss.
The heat collector will, however, need to be installed outside where it can get maximum sunlight. In line with its indirect solar water heating system, the manufacturer provides 2 gallons of Propylene Glycol. This is the anti-freeze liquid that goes through the collector loop.
If you are new to solar water heaters, you should know that in indirect systems, the water and the heat collector don’t come into contact with each other. Instead, the anti-freeze fluid flows through the collector, gets heated up then flows to the heat exchanger. This component transfers the heat from the anti-freeze liquid to the water.
Additionally, there is a controller for the said pump so you can control the flow of the Propylene Glycol. Before purchasing this solar water heater, you should know that only the accessories mentioned above are included. As such, the plumbing required to connect the collector to the tank and pump is left out. Consequently, ensure you budget a bit of extra money to buy pipes and more if you choose this as your purchase.
Also, due to the capacity of the tank, you expect the whole system to be relatively bulky. As such, ensure you have enough space to spare before deciding to pick this system.
What we liked:
Offers a large capacity water tank
Comes with a pump and controller so you can make the best use of the system
The pump is submersible
What could be better:
Requires you to purchase extra plumbing to connect the collector and the tank
A more straightforward solar water heater design is available in the Sunbank Solar 40 Gallon Solar Water Heater. This makes it ideal for DIYers since they won’t have to spend extra funds to get the tool installed professionally. Both the collector and the tank are fused into one device, unlike what you get in an indirect system.
Due to the model’s design, there are some things that you would find in an indirect system that are absent in the 40-Gallon Sunbank. Among them is the anti-freeze liquid. This is because the collector and water feature direct interaction for the latter to heat up.
Noteworthy is the efficiency of the tube solar collectors. They can absorb up to 96% of solar radiation. If you were to compare that with solar photovoltaic (P.V.) panels, the latter would be blown out of the water. After all, the tube solar collectors seem to absorb about six times more energy.
The image above also clearly shows the 40-gallon tank. The tube collectors heat the water in the tank to sufficient temperatures throughout the day. Also, the tank is well insulated to prevent heat loss.
Some might point out that the insulation is not 100% effective in keeping heat inside the tank. Nonetheless, even after a whole night where no sunshine is experienced, the drop in water temperature is so minimal as to be negligible.
Also missing from the setup is a pump. Nevertheless, the device manages to make do without it. It uses the incoming cold water to push the hot water out of the tank when you open a faucet.
Of course, with the tank and the collectors being joined together, there is no need for glycol as well. Lastly, buyers also get a 10-year guarantee to protect their purchase.
What we liked:
Relatively easy to install
Relatively large capacity
No moving parts
High heat retention capabilities
What could be better:
The weight of the system may be too much for some roofs
Another solar water heater that can cater to the needs of a large family is the Duda Solar 300 Liter SUS304 Passive Water Heater. This is a passive water heater like the Sunbank Solar 40 Gallon Solar Water Heater. As such, there is no Propylene Glycol in the purchase, nor is it needed.
The tool is similar to the Northern Lights Group 30 Tube Solar Water Heater Collector and the Duda Solar 30 Tube Water Heater Collector in that it incorporates 30 tubes in its construction.
An exciting feature that is included is the settings controller. This way, if you are sure you don’t need hot water for a specific duration of time, you can turn the device off. To complement the controller, a temperature display for the tank is also incorporated.
Seemingly there are different finishes available for the machine. The painted one is for general application. However, there is a stainless steel option that improves the aesthetics of the solar water heater. There are also galvanized solar water heaters for use in areas such as beaches. This protects it from damage caused by seawater.
Also included in the tool is an electric backup heating element. This solar water heater is also among the top performers when it comes to heating efficiency. After all, it does convert about 94% of the sunlight it comes into contact with heat.
The tool also incorporates stainless steel in the construction of both the outer shell and the stand. Additionally, the system is hailstone resistant and is expected to last at least 15 years.
What we liked:
High energy conversion rate
Different finishes are available for different environments
A large water storage tank is included
Winter and hailstone resistant
What could be better:
The product lacks installation and use instructions
This Duda Solar Product gets a 5 out of 5 in its ratings on Amazon. Admittedly not many people have reviewed the product, but it is still a sign that the manufacturer is doing some things right.
There are, of course, different configurations for the same product for different budgets. They include a 15-tube, 20-tube, 25-tube, and 30-tube option. The one on the list, as depicted by the name, is the 30-tube system. Worth noting is the manufacturer gives users a few spare tubes to cater for accidents.
Also, different options are available depending on how you want to install the system. One of them is a 45-degree product that works best for a flat roof. The next is a 37-degree product, and the last is the slope roof option.
Like the other Duda solar water heater on the list, this product is one of the most efficient at converting radiation from the sun into heat. The tool does have limitations in the pressure it can handle. Consequently, try to ensure that water flowing to the heater does not exceed 87 psi.
Additionally, the maximum flow rate is about 5.25 gallons per minute. The product should, therefore, comfortably handle your showering and hot water use needs.
Remember that the tool can heat water to around 205 degrees Fahrenheit. This being the case, you need to be careful not to burn yourself when you turn the hot water faucet on. If you add cold water to the equation, you will be able to bring the temperature of the water down. Be careful not to overdo it.
Other pros of the product include the fact that it is hailstone and winter resistant. Given that it stays outdoors year-round, these features allow the product to reach its rated lifespan of 15 years without any hitches.
What we liked:
High heating efficiency
What could be better:
Most of the users of this product have nothing but good things to say about it
Giving the Duda solar water heaters a run for their money is the Northern Lights Group 30 Tube Solar Water Heater Collector. You will realize that with most of these machines, the insides of the tubes are coated by highly absorbent materials. The most common coatings are made of aluminum and aluminum-nitrogen material, which is often effective in its absorption duties.
When you analyze the Northern Lights Group 30 Tube Solar Water Heater Collector, you realize that the manufacturer has gone a step further in the making of the tubes. The ones on this heater contain not only the aluminum and aluminum-nitrogen layer but also separate copper and aluminum layers as well. This reportedly enhances the absorption properties of the tool.
The added layers have been known to stabilize the coating. As a result, an extended lifespan of about 20 years is expected of the whole device. Another benefit is that these layers offer better heat conduction.
Also, the SRCC OG-100 Certification shows that excellent performance is to be expected from this device. The tool is CSA certified, as well.
Another positive you can add to the list of pros is the water pressure capacity of the system. At 116 psi, it can handle a lot of the home needs that you throw at it. Also, on the list of positives is the five-year warranty.
What we liked:
Durable construction and 20-year lifespan
Efficient heating due to the “3-Hi” construction of the tubes
The product is certified by multiple groups
What could be better:
The product doesn’t come with a storage tank for hot water and as such may not be able to provide hot water at all times
Here we have a solar water heater that works well for your home swimming pool. As you can expect, the tool is rather bulky since it will have to cater to large amounts of water. However, the maximum temperature to expect from using this device is around 10°F. Remember that this is for a swimming pool and not for showering, and hence you shouldn’t expect the water to reach extreme temperatures.
Please note that the manufacturer uses a polypropylene heat collector. Among the benefits of this is that installation is more or less a walk in the park. Also, the material is corrosion-resistant, so leaving it out in different types of weather should be okay.
The whole device comes with an 80 square feet solar panel. As such, before purchase, make sure you have enough space for the installation of the panels. They can also be installed on your roof like other regular solar panels.
Also, the manufacturer helps you cut down on costs by making it easy to install for a DIYer. As such, professional installation assistance may not be required.
The product works best with in-ground swimming pools. Additionally, there are some available accessories, such as reel systems and liquid heat shield. The former allows you to apply and remove your solar blanket with relative ease.
The liquid heat shield reduces heat loss from the pool by reducing water evaporation. Also needed for the full function of the system is an installation kit. This is, however, sold separately.
The GAME 4721-BB SolarPRO Curve Solar Pool Heater is an alternative to the Smartpool S601P SunHeater Solar Heating System. If you have either an in-ground or an above-ground pool, this may be precisely what you need.
As you can see mentioned above, the tool is meant for use with an 8000-gal pool. Nevertheless, buying two or three of these to cater to a larger pool isn’t against any rules.
Also, it may take up to four days for the product to turn the heat up to sufficient levels. If you feel like this is too long, you can look at other options as well.
The product imaged above shows a curved design that may not be everybody’s cup of tea. There is, however, another contour shaped option available. Anyone considering this alternative should know the price goes up by more than $50.
Users will also notice the adjustable legs on the solar water heater. These should help get the most sunlight by positioning the tool adequately. Additionally, the device is meant to withstand constant exposure to sunshine and rain.
Also, part of the design is a transparent cover whose purpose is to trap heat. This is the same heat that is used to raise the temperature of the water in your pool. Finally, the manufacturer adds threaded ports that make it easier to attach pipes that feed into the pool.
What we liked:
Easy to install and use
What could be better:
Takes relatively long to raise temperatures of a pool
The capacity for one of these solar water heaters is not very large
The Heliatos Complete 2 Panel Hybrid Solar Water Heater Kit is unique on this list since it is a hybrid system. This means it incorporates both solar panels and heat pipes in its construction.
For this solar water heater to work optimally, you have to connect it to your current electric or gas water heater. However, you will have to purchase the pipes that you will use to connect the panels to the water heater. Do remember that the pipes you buy need to be a 1/2” in size.
Another thing you have to consider before purchasing the pipes is that they have to be insulated, so they don’t lose heat. When you do buy this product, you find out that the basic set comes with two panels. However, you can add two more if you feel they will serve your needs better.
It should be noted that with this purchase, you do not have to solder your panels together. The manufacturer also adds an extra panel to the purchase. This component is quite small, seeing as though its sole purpose is to power the pump. This also eliminates the need for the water heater to be connected to the power grid in the house.
A few other accessories are added to the package, including the pump and the instructions for installation. However, you may need to supply the tools that will help you put the device together.
What we liked:
You can combine up to four panels as you put together this hybrid solar water heater
Easy to install
The tool comes with an extra panel for powering the pump
What could be better:
You may have to purchase a few extra supplies to install the system
Just because you have decided to go camping does not mean that you have to shower with cold water. Instead, you could make use of the PGYFIS Solar Shower Bag. Its capacity is almost 20 liters, and as such, it can often be used for more than one shower if full.
It is recommended that you use hot soda water to clean the bag before you use it. Once clean, you can fill the bag up with water for use. Remember that it needs about 3 hours of exposure to the sun for the water to be hot enough.
Included in the design of the bag is a temperature indicator. However, ensure you test the temperature of the water with your hands to be safe. If it is too hot, there is no rule against removing some of the hot water and replacing it with cold water. This should help even out the temperatures to a suitable degree.
The bag is made of PVC material, which is not the most durable material. As such, coming into contact with a needle or any other prickly material is likely to ruin it.
On top of the bag is a handle strap that you can use to hang it on trees. On the bottom side, there is a hose and a showerhead. The controls allow you to turn the shower on and off. You should as well be able to tweak the flow and water pressure to desired levels.
Another device meant for pool use makes it onto our list. This time it is the Solar Pool Supply Universal Solar Pool Heater Panel Replacement. Due to the high manufacturing standards, this tool can last between 15-20 years. Also, since the manufacturer is confident of the quality they provide with this product, buyers receive a 10-year warranty as well.
The tool is uniquely constructed to feature a tube-and-web design. As such, the normal expansion and contraction of the panel is accounted for. Consequently, you don’t expect the device to get damaged as a result of these processes.
Also, the tool incorporates measures that help prevent hot spots. Users should know that it is compatible with all 2” I.D. / 2.375″ O.D. header manifolds. As such, it can be used to replace most solar pool heater panels of the same caliber.
Lastly, you are advised to install the product vertically if you would like to achieve optimal performance.
What we liked:
10-year limited warranty
What could be better:
The solar water heater is not complete on its own and has to be coupled with other devices that you may or may not already own
Things to Сonsider
While we may not be there when you pick up your solar water heater of choice, we can help you navigate the situation. Taking into account the information in the below buying guide is part of the process.
What is a solar water heater, and how it works?
The solar water heater harnesses the sun’s energy to be used in heating water. Of course, people use this variation of a water heater since it is environmentally friendly and helps them save on their electricity bill.
Solar water heaters work differently depending on how they are designed. For some, water is passed through the collectors, which have a tubular design. The collectors, in turn, absorb solar energy and use it to heat the water passing through.
For others, the collector and the water does not come into contact with each other. Instead, anti-freeze liquid picks up the heat from the collector, transfers it to a tank where the heat exchanger component then transfers the heat to the stored water.
It is important to note that there is separation between the hot and the cold water in most of the solar water tanks.
Benefits of solar water heaters
If you are contemplating solar water heaters in comparison to other types of water heaters, you are going to want to know the benefits that come from such a system. One of the most obvious ones is the lower carbon footprint. Remember, the use of solar doesn’t produce fumes, and that reduces the negative impact you have on the environment. Most other water heaters may use energy that comes from the burning of fossil fuels.
Solar water heaters can as well help save some money. It is no secret that water heaters use a lot of energy. When you use electricity or gas to heat your water, you end up paying some relatively high utility bills.
In contrast, solar water systems are a one-time cost that involves the purchase and installation of the machine. After that, it is free. While it can be expensive in the beginning, it is bound to save you a lot of money in the long run.
Another benefit is the low maintenance of the system. Some of these solar water heaters will last years after installation before needing any form of maintenance. However, checking often prevents the build-up of problems to the point of no return.
If selling your home is part of a long term plan, you may also want a solar water heater. It adds tremendous resale value, thereby raising your home’s price to something more desirable.
When compared to other types of solar devices, the collectors on solar water heaters convert more than 80% of the sun’s radiation into heat for your water. You may also come across some tax incentives that encourage you to buy these devices.
Things to consider before buying a solar water heater
In your search for a solar water heater, you may realize that each option is made for a different market. As such, making sure you understand the niche you are in will help you narrow down your choices much quicker. For you to do this, you may need to do some research on your lifestyle. Things like where you live may matter more than you think. In addition to your location, we have listed a few of the things you need to consider before you enter your payment details on Amazon.
Where you live does affect the solar water heater you purchase. For some of the devices mentioned above, people are advised to go with the galvanized steel option since it handles seawater better than other finishes. This is apparent in the Duda Solar 300 Liter SUS304 Passive Water Heater. Nevertheless, there are other options as well that work for other climatic regions.
You may as well be in an area that experiences lots of cloud cover day in day out. In such areas, you may have to look for the most efficient collectors to make sure you get the most out of the little sunlight that you get. Remember, you might have to position your device according to your location as well. This applies mostly to the collector. This requires planning even before you start looking at your available options.
The amount of water you need
Most people use solar water heaters to raise the temperature of the water they use to shower. As such, purchasing such a device requires you to find out how much water you need for the exercise. It makes no sense for a family of five to buy a machine that caters to three people. The rest may have to shower with cold water, hence why you should be deliberate with the capacity you choose.
How green you are
Some people want to do as much as they can to reduce their carbon footprint on the environment. As such, they might need a solar water heater that caters to all their heating needs at all times. However, others may be willing to let the electrical power in the house handle some of the heating.
Remember that some of these devices can be used in conjunction with electricity, while others can’t. If you are looking to do the most you can for the environment, the independent solar water heater is what you should be looking for.
The pressure system in your house
Water pressure also varies from household to household. This makes it necessary for you to be aware of the pressure in yours before committing to a purchase. That way, you ensure compatibility between the water pressure and the device that you bring home. Nevertheless, some plumbing accessories may help you regulate the water pressure coming into your home.
Do you need to heat a swimming pool?
While most people need hot water for showering and use inside the house, some need it for their swimming pools. However, unlike solar water heaters for indoor home use, the effect of such a device on a pool is often minimal. It can even be less than 10°F.
Nevertheless, you do have to remember that while people do want warmer water in their swimming pools, they don’t want it to reach boiling levels. After all, hot water can lead to burns, and unlike inside the house, there is no cold water to regulate the temperatures.
That being said, it isn’t necessary for you to heat a swimming pool. You can swim in cold water if you like. However, heating the water a bit makes the whole experience a lot more enjoyable.
Most people have limitations as to the amount of money they can spend on a solar water heater. If you don’t have such constraints, you may be one of the lucky few who has limitless options. However, if you belong to the other section of the population, you have to purchase a solar water heater that you can afford. The prices also vary from hundreds of dollars into the thousands.
Features to consider before buying a solar water heater
Even if they save you money in the long run, the initial purchase of a solar water heater can be expensive. As such, you don’t want to get it wrong as that will have you spending more money with little satisfaction in the product you receive. Instead, you can look at a list of features beforehand and make your decision based on that. This is in addition to customer reviews, price, and perceived benefits.
However, if you know nothing about solar water heaters in general, you will look at the stated features and not know what they mean. This can be detrimental to your purchase process; hence you should take up the challenge to educate yourself on said features. With a list of the same as well as all that you need to know about certain solar water heater features given below, all you have to do is keep reading.
It is quite likely that the Duda Solar 300 Liter SUS304 Passive Water Heater can service the needs of a large family. This is because the 300-liter capacity is quite large. Compare that with the Sunbank Solar 40 Gallon, which may not be able to handle the needs of a five-person family, and you can see the difference. Nevertheless, some households don’t have as many people. The key to navigating the purchase in this area is making sure that you have enough capacity to cater to all the people in the house.
The same is the case for pool solar water heaters. You will notice that these devices have limits as to the size of the pool that they can service. However, for some of these heaters, you have the option of combining two or more to boost the capacity.
Also, the types of solar water heaters you may encounter in your search for the ideal system are quite numerous. Among them are the following.
Active direct solar water heaters: This is one of the more common types that you will encounter. Water flows from the house into the collectors, where it is heated and pushed back into the house. In warm climates, this is one of the preferred systems.
Active indirect water solar water heaters: These are also relatively common. The Duda Solar 200 Liter Water Heater is an ideal example of this type of heater. You will notice all of them have some sort of fluid that picks up the heat from the collector and transfers it to the heat exchanger. The heat exchanger then transfers the heat to water in the tank.
The glycol fluid flows through the collector into the tank and back. Since the water containment is positioned away from the collector, this system is ideal for cold climates. Often it is stored inside the house, and that helps with heat retention in the water.
Passive thermosiphon water heaters: These systems are all the same in that the heater is installed below a storage tank. When the water is heated, it slowly rises to the top of the tank leaving the cool water below to be heated as well.
Flat-Plate glazed solar water heaters: One of the unique design features of these devices is that they incorporate copper tubing that is placed on a metal plate. Also, they come with glass coverings and are similar to active indirect systems in that they use transfer fluid and a heat exchanger. In an ideal situation, they are installed to heat pool water in areas with cold climates.
Panel systems: If you want a portable solar water heater, you should look into panel systems. They heat relatively small amounts of water while it is in a stagnant position.
Passive integral collector-storage water heaters: Their construction mostly involves the use of metal plates that heat water in small amounts. The water, of course, has to go through the solar water heater before it is returned to a storage tank. If you only need hot water during the day and live in hot climatic conditions, this may be the system for you.
Flat plate unglazed water heaters: These are similar in construction to the flat-plate glazed heaters in a lot of ways. Nevertheless, they don’t feature a glass enclosure. Instead, they incorporate heavy-duty rubber and an open design. They as well are meant for pool use.
However, you also have to realize that some options don’t even have such tubes. They use a different methodology to heat the water.
Consequently, you need to be keen to note the type of tubing, its benefits, whether spares are included, and any other benefits that may be provided.
Solar water heaters are among a list of long-term investments that you may have to make for your home. As such, you hope that they will last a long time after purchase, thereby allowing you to recoup the purchase price and save you even more money. Some of these devices offer information on how long they are expected to last. An impressive option is the Northern Lights Group 30 Tube Solar Water Heater Collector, which is expected to last 20+ years.
Ease of use
Another thing you should want from your purchase is that it won’t be too difficult to use. This makes your whole experience with the product better since you don’t have to struggle to regulate temperature and change settings.
A lot of you will want a solar water heater for your home. In this case, it doesn’t have to be portable, as most homes are permanent. However, some of you may want something to take with you on camping trips. Bulky devices will be impossible to fit in your car, and you won’t be able to lift them. In such a scenario having a solar water heater like the PGYFIS Solar Shower Bag could be extremely beneficial.
Encountering unique extra features is something you should expect in your shopping process for a solar water heating system. Some are meant to help you in the installation process with the example of the adjustable legs in the GAME 4721-BB SolarPRO Curve Solar Pool Heater. Some features are as well meant to make the device more comfortable to use. If you encounter them and you feel they add sufficient value to the purchase, you can add them to the reasons why you should purchase a specific solar water heater.
Solar water heaters don’t convert the radiation from the sun into electricity. Instead, they use thermal energy to heat the water. As such, you don’t need solar panels as part of the installation. It is, however, possible for you to use a solar water heater in conjunction with a panel or two.
Some people may opt to use an electric water heater. This is different from the thermal option available in most solar water heaters. In this case, it becomes necessary to connect the heater with solar panels. This type of water heater can also work if you hook it up directly with the electricity in your house.
Solar water heaters will work both when the weather is clear, and when there is cloud cover. Nonetheless, some of these systems incorporate either a gas or electricity back up so that it can kick it if the device doesn’t raise the heat of the water to the required temperature.
A regular maintenance schedule should be kept and adhered to so that problems don’t creep up on you when you least expect it. Among the things you should do is to always check the machine for damage. Pay attention to both the frame, the solar collectors, and the tank if it is available.
If you notice broken tubes in the setup, replace them as soon as possible. Checking pipe installation should as well be a priority. Remember that a lot of heat can be lost in the piping if it isn’t insulated correctly.
Another thing that you may encounter in your inspection is vegetation around the device. This, of course, needs to be removed before it causes damage to the equipment. In some scenarios, you may need to flush the water tank to remove sediment. This should improve the longevity of the water container.
Also, another problem that may come up is rust in plumbing. Check for this as well. Finally, cleaning the whole device with only clean water should be done regularly.
For a small or medium-sized family, the Duda Solar 200 Liter Water Heater seems like an excellent pick. With its active indirect system, you will likely have a continuous supply of hot water any time you turn on a faucet. This is because the hot water is stored in a tank inside the house.
Also, the controller should be beneficial in determining the hot water output of the system. Behind the Duda Solar 200 in our rankings is the Sunbank Solar 40 Gallon Solar Water Heater. It also has enough capacity for a family of about three people. Another impressive aspect of the product is the effectiveness of the tube collectors. With an efficacy of about 95% and enough storage, running out of hot water will be something users completely forget about.
For the larger families, the Duda Solar 300 Liter SUS304 Passive Water Heater seems like the best pick. Users who consider this purchase mostly do so because of the capacity. However, the winter resistant construction, durable body, and the pressure rating are all top features.
These three, we feel, are more suited to a variety of applications and would serve most families well. However, differing with us on this matter is not against any rules. If you do feel like any of the other seven solar water heaters deserve a place in our top three picks, you can tell us why in the comments section below. Also, if you have gotten this far, you probably have enough data to make a decision that you are unlikely to regret.