How to Choose Solar Water Heater?

It’s not a secret that having hot water adds to our electricity or gas bills. But did you know that hot water actually makes up a whopping 30% of the average electricity bill? You’ve somehow landed here, so chances are, you do. Or it may also be that you’re looking at better ways to generate hot water for your home.

We never want to disappoint, so we will provide some valuable insights into choosing the best solar heaters.

What to Consider When Buying Solar Water Heaters


Get the best value for your money by picking a solar water heater packed with features useful to your household. Here are our top three considerations when looking for a solar water heater.


  • The capacity of a solar water heater is expressed in liters or gallons.
  • Before looking at the solar heater’s capacity, you must have an idea of your household’s daily hot water needs.
  • Another general trend in determining the ideal solar water heater capacity is household size. For example, a two-person household needs at least 115 L capacity and a three-person household at least 152 L. A family of four would require 190 L, while larger families of five or more require at least 303 L.


  • There are many solar water heater types, but these can be grouped into two main categories: active or passive systems. There is no right or wrong type when it comes to solar water heaters. It just depends on your needs, installation location, and how much you are willing to spend on some extra accessories.
  • Passive solar water heaters operate differently from traditional water heaters. Instead of relying on gas or electricity, they use your existing water system’s water pressure to get the water moving. Passive systems don’t require pumps but rather have water storage tanks directly connected to heat collectors.
  • On the contrary, active water systems need a pump to move water around the heat collector. It ensures that water within the tank stays warm while preventing water within the heat collector from overheating.
  • Another key difference is that active systems require some electricity to get the pump working. The energy requirement is only a tiny amount and can usually also be powered by small solar panels.

Portability and Size

  • Perhaps the first thing that comes to most people’s mind when hearing a water heater (solar or not) is the home. But what we tend to forget is that water heaters are also needed when we’re on the go. Wouldn’t you want a warm shower when camping out in the cold? This is why we think portability is important.
  • With home solar water systems, it’s also important to consider the size. The size we’re talking about here is more about your rooftop rather than how much it can hold.
  • For example, solar water heaters with integrated collector storage can weigh more than 400 lbs. This means that you need to ensure your roof can withstand this weight before purchasing it.
  • Another example is if you have more space over your roof than on the ground. In this case, you would probably want to go with solar water heaters that fit the roof. This way, you can better utilize the limited space you have on the ground.

Solar Water Heater Frequently Asked Questions


How does a solar water heater work?

  • To understand how solar water heaters work, you must first familiarize yourself with the system’s components. A solar water heater system has a storage tank and a solar collector.
  • The collector is usually an insulated box-shaped unit connected to tubes that turn solar energy into heat. Water is then heated and stored as it passes through the solar tubes.
  • Some water heating systems also have heat exchangers.  It heats water, which subsequently flows through the tank’s copper coils. The exchange happens when the heat transfers to the tank and the cooled water returns to the collector.
  • The most important thing to remember with solar water heaters is they use thermal energy instead of converted solar energy. It is what sets it apart from other solar-powered solutions. Standard solar panels convert solar energy into electricity. Solar water heaters directly heat the water, so there is no energy conversion required.

Do solar water heaters need solar panels?

  • Because most solar water heating systems use thermal energy instead of electricity, no grid connection is needed. The only exemption to this is when using some portable solar water heaters.
  • Remember, though, that you can always get electric water heaters that connect to your solar grids. These systems are technically considered solar-powered systems because the electricity comes from harvested sunlight. However, they aren’t considered solar water heaters in the strictest sense.

How much money can you save by switching to solar water heating?

  • Like any solar-powered system, initially, you will be spending more instead of saving money. The initial investment with most solar technologies doesn’t come cheap, but the savings eventually reveal themselves in the long run.
  • Initial costs aside, your potential savings all depend on a few factors. These factors include your average hot water usage when you use it, and your heater’s energy factor rating. Generally, however, solar water heating systems have the potential to cut your power bill by anywhere from 50% to 80%.

Solar Water Heater Reviews

1. Heliatos Hybrid Solar Water Heater Kit

Heliatos is an Amazon retailer and leading manufacturer of solar water heater panels. Their Amazon listings include water heating system parts and complete water heating kits.

The best feature of the Heliatos Hybrid Kit is, as its name implies. It comes as a complete solar water heating package. It has four heating panels, a circulation pump, fittings, and a 10W solar panel for powering the pump.

Although this kit comes as a set of four panels, the Heliatos is designed to allow the threading of panels together. This means you have the power to adjust the capacity of your solar heating system to suit your household’s needs.

Another unique feature of the Heliatos kit is its versatility, thanks to its hybrid design. It is a solar water heater in itself, yet it connects to your existing gas or electric heater. It’s really a great feature because it means a couple of good things.

First, it’s a great option if, for some reason, you don’t want to go fully solar. The Heliatos kit can warm up your water, so you at least have warm water during the day. If you want it hotter, the kit preheats water and feeds it into your existing water heater.

That way, you still get to cut your gas or electricity bills somehow. The second is that a hybrid system is great during cloudy days as you know that your existing systems can still do the heating for you.

Easy installation is yet another key feature of the Heliatos heater. The heating panels are super lightweight and already come with brass fittings, so you wouldn’t have to do any soldering. They’re also flexible with installation, as although the panels are ideal for roof mounting, you can still mount them elsewhere.

Finally, the Heliatos panels are made to last thanks to their heavy-duty aluminum framing and mounting brackets. Heliatos also offers a one-year limited warranty and a 10-year leak cover, except for leaks caused by freezing.

The only setback to the Heliatos heating system is that they are not freeze-proof. If you’re living in areas prone to extremely cold subzero temperatures, this may not be the solar heater for you.

Overall, however, the Heliatos is the top choice for a solar water heater thanks to its hybrid, versatile, flexible, and durable features.


  • Complete kit.
  • Adjustable capacity – add panels to suit your household’s solar heating demands.
  • The hybrid design allows both solar and electric or gas to work together for heating.
  • Heavy-duty, long-lasting material.
  • 1-year standard warranty and 10-year leak warranty.


  • Not suitable for areas exposed to subzero temperatures.


2. Sunbank Solar Hot Water System

Sunbank Solar is an Australia-based company specializing in solar power technologies and their installation.

This Sunbank product is a passive solar water heater with 40 gallons or roughly 151 L of capacity. The Sunbank has an extensive range, allowing you to opt for the larger 80-gallons if you have a larger household.

The Sunbank is an extremely efficient solar water heater. It’s high-density polyurethane insulation, and evacuated tube collector design allows it to absorb anywhere between 92%-96% of solar radiation. As long as your heater is exposed to sunlight, it’s efficient enough to ensure a consistent hot water supply.

Another appealing feature of the Sunbank is its ease of installation and low maintenance. The Sunbank comes as a complete system without any movable, detachable, or extra parts. This straightforward design makes it less intimidating to deal with, unlike the intricate assemblies of advanced solar systems. In short, it’s a great solar water heater for beginners in solar.

It’s also flexible in that you can mount it on the roof or on the ground.  You can basically install it whatever is more convenient for you and wherever has better sunlight exposure.

Speaking of versatility, it can also be used independently or in conjunction with your existing electric or gas water heater.

Lastly, the Sunbank solar water heaters come with a 10-year heat collector warranty, giving you added reassurance for your purchase.

The only reason Sunbank is not our top pick for the best solar water heater is its price. The initial cost of getting a Sunbank solar water heater is a bit high. But then again, considering all the benefits above plus the long-term savings, it is well worth the investment.

In short, if you want to invest in a high-end, feature-rich passive solar water heater, Sunbank is your clear winner.


  • Extendable capacity.
  • Efficient – absorbs 92-96% of solar radiation.
  • Easy installation and low maintenance.
  • Versatile mounting options.
  • Works independently but can be connected to your existing water heaters.
  • 10-year heat collector warranty.


  • Relatively expensive.


3. Duda Solar 30 Tube Water Heater Collector

Duda Diesel is an Alabama based company offering a wide range of alternative energy solutions. Their popular products include biodiesel and solar water heaters.

The flexible configuration is one of the great features of the Duda Diesel water heater collector. Currently, the tubes are available in 15, 20, 25, or 30 tube configurations. Having these options allows you to choose the capacity suitable for your household’s size and hot water needs. Choose from the 15-tube system with a fluid capacity of 0.9L or the larger 30-tube system with a fluid capacity of 1.7 L.

Another versatile feature of the Duda hot water collectors is seen in its installation options. Depending on your preference, there are three different installation options to choose from when purchasing the Duda collectors. They have a 45-degree option, which is ideal if your home has a rather flat roof. They also have 37-degree and sloped options suitable for other roof types.

The Duda collectors also have great heating efficiencies. It has a 93-96% sub absorption efficiency and can heat water up to 250°F. This absorption rate makes the Duda Solar Tubes among the most efficient solar water heating systems in the current market.

Lastly, the Duda collectors are winter and hailstone-resistant, making them a great option for colder climate areas and all-season use. Because of these weatherproofing properties, the Duda collectors are predicted to last a long lifespan of up to 15 years.

Perhaps the only drawback to the Duda is that it’s limited to the water pressure it can handle. You must ensure that this heater’s water flow rate doesn’t go above 87 psi to prevent damage and malfunction.

The next thing is related to installation, but it’s a really minor issue, and it boils down to the user/installer. The header tube holes take a bit of time to align properly, making setup and assembly just a bit time-consuming.

In summary, the Duda Water Heater Collector is a great option for an efficient and versatile roof-mounted solar water heater.


  • Flexible configuration and capacity.
  • Versatile installation modes.
  • Great heating efficiency.
  • The long life span of up to 15 years – winter and hailstone-resistant.


  • Limited water pressure capacity – must not go above 87 psi.
  • Setup takes time due to header tube hole alignment.


4. ADVANCED ELEMENTS 5 Gallon Solar Shower

The next item on our list is for our camping and outdoor enthusiasts. It comes from Advanced Elements, an American company offering a range of outdoor products. The Summer Shower is Advanced Elements’ answer to your portable solar water heater.

The Summer Shower range comes in a good range of capacity options. The smallest one has a 9.5 L capacity, the midrange accommodates just under 19 L, and the largest carries nearly 37.9 L.

Essentially, all you need to do is fill the Summer Shower with water and keep the unit exposed to direct sunlight. Shortly after, you should be able to enjoy a warm or hot shower within a few hours. The time it takes to heat up the water is all dependent on the amount of direct sunlight exposure.

The heating mechanism of the Summer Shower is rendered by its innovative design. It comes with a miniature solar panel that passes on the sun’s energy to the water inside a reservoir. The insulator layer maintains the heat inside the reservoir, while reflector panels work to send more sunlight toward the solar panels.

The Summer Shower system is also made of premium quality, long-lasting materials, which is always a key consideration for outdoor gear. The entire system has a four-layered construction, which makes it super durable and optimizes its capacity to retain heat. It’s also PVC free, so it’s not you’re reassured it’s safe for you and the environment.

This portable solar water heater is very easy to use. It has an on/off shower head that is user-friendly and helps you make use of the stored water efficiently. The extra-large filling valve and convenient twist-off cap help avoid spills and make filling the unit super quick and easy.

In addition to the essential water heating elements, the Summer Shower is also packed with convenient added features. It is lined with Velcro straps to conveniently hold your washcloth or any other showering needs.

It also comes with a wide handle grip, so it’s easy and comfortable to carry around. Finally, it has a convenient pocket for storing your toiletries. It also comes with a hanging pocket mirror for your grooming needs.

The only issues we’ve noted with the Summer Shower are quite minor and all point to design. First, we found that the nozzles tend to come off with extended use. This isn’t a major problem as it easily goes back on again. But then again, it would probably be better if it had a more permanent and stable design.

Another thing is that the unit could have done with a dedicated clip to hold it in place during transport. We found that the Velcro straps do the trick. However, a dedicated clip would probably work better to allow the Velcro to be used for other stuff.

In summary, the Summer Solar is perhaps your best solar water heater option for use during your camping trips.


  • Portable solar water heater solution.
  • Innovative design.
  • Premium-quality durable materials.
  • Easy to use with added convenient features.


  • Could do with a clip to hold the showerhead in place during transport.
  • The nozzle could do with a more stable and permanent design.


5. Sportneer 20L Solar Shower Bag

If you liked the previous product we just went through, you might also want to like this next one. It’s the same portable solar water heater, but this time from a different brand.

Sportneer is a Chinese company specializing in an extensive range of outdoor and fitness gear.

The Solar Shower Bag is Sportneer’s version of the portable water heater. This handy solar water heater is about the same as the Summer Shower, with just a few variations in features.

One key difference is that the Sportneer has a temperature indicator. This addition gives you a good idea of how hot (or cold) the water is at the current time.

Another feature that sets the Solar Shower Bag apart is its clever color-coded design. The front of the panel has a highly visible army green color, and the back is lined with purely gray material. This color distinction makes it easy to spot and easy to use. The key is to remember to always have the green side facing direct sunlight.

In terms of efficiency, the Sportneer also ranks pretty well, considering it’s a portable solar heater. In ideal direct sunlight conditions, it takes about three hours to heat 20L of water up to 113°F.

Like our previous portable heater, the Solar Shower Bag also comes with additional features adding to its convenient use. It has a wide-diameter water inlet that allows quick and efficient water filling.

It also has a handle strap to help with easy transport and hands-free showering. Additionally, it has a handy mesh storage pocket to hold your showering essentials. The other advantage of the Solar Shower over the Summer Shower is the dedicated showerhead nozzle clip. It’s definitely a great design addition to ensure the nozzle is kept secure when not in use.

The one thing that made the Sportneer’s Solar Shower Bag inferior to the Advanced Elements’ Summer Shower is capacity. The Solar Shower Bag, unfortunately, only comes in the 20L size. It’s a good capacity on average, but not as versatile as the Summer Shower.

Another minor issue we have with this Sportneer product is the location of its temperature indicator. The current design has the indicator located at the back of the bag on the gray side.

It would have made more sense for the temperature indicator to be located on the green side. This is the side that’s facing the sun when trying to heat water. So naturally, it would have been more user-friendly to have the indicator located on the front, sun-facing side.

In summary, the Sportneer Shower Bag is the ideal choice for a mid-sized portable solar water heater that allows temperature monitoring.


  • Temperature indicator.
  • Clever, color-coded design.
  • Efficient – heats 20L to 113°F within three hours.
  • Packed with additional convenient features.


  • Available in only one size/capacity.
  • Impractical location of temperature indicator.


6. MH-38 Marine Solar Water Heater Panel

Our next solar water heater is another one from the Heliatos brand. It essentially has all the features of the first Heliatos product on this list, except that this one was specifically made for life at sea.

The Heliatos MH-38 was developed based on the Heliatos SW-38. If we’re not mistaken, the MH-38 is probably the only marine solar water heater in the current market.

Heliatos paid particular attention to the anticorrosive properties of the MH-38 to ensure it specifically suits the harsh ocean conditions. The MH-38 has a powder-coated frame and backing, a sealed construction, and stainless-steel hardware. The inner structure of the MH-38 was also reinforced with zinc-phosphate for internal corrosion protection.

Other than corrosion, the MH-38 was also built to last. It has an extremely tough and thick aluminum frame and backing and durable and unbreakable polycarbonate twin-wall glazing.

Just like the SW-38, the MH-38 is extremely lightweight at only 12 lbs, making it an ideal addition to your boats or beach cabins. It also comes at a manageable size of 2 ft x 2 ft for each panel.

Of course, the MH-38 is also easy to install, and easy to thread into each other, so you can combine a few panels together for added capacity.

Just like most of Heliatos’ panels, the MH-38 is an active heating system, which means you’d also need a pump to get the water circulating.

Although the 24 inches x 24 inches size may be portable and easily manageable, it may be too small for larger marine vessels. The only saving point is that these panels easily thread to each other, so there’s always that option of expanding capacity to suit your vessel.

Overall, the MH-38 is the best option for a solar water heater fit for life at or by the sea.


  • The only solar water heater specifically designed for life at or by the sea.
  • Comprehensive anticorrosive properties, including internal corrosion protection.
  • Built to last – aluminum frame and backing, polycarbonate glazing.
  • Extremely lightweight and manageable size.


  • Active water heating system – requires a pump for water circulation.
  • It may be too small for larger marine vessels.


7. Clean Republic Solar Evacuated Tubes

best solar water heater system

The Clean Republic is a Washington-based distributor of alternative energy solutions. They are well-known for their electric bike line, but they also produce solar water heaters, lithium batteries, and more.

The next product on our list is Clean Republic’s solar evacuated tubes. These tubes come in a pack of 10 and are extremely versatile in terms of functionality. You can use them as standalone water heaters or configure them to build a custom solar heating system. This flexibility also means that you get to decide on the capacity of your solar heating system. They’re great for off-grid hot tubs, rooftop solar, and other solar engineering projects.

The tubes themselves are relatively compact at 20.5 inches long and 58 mm in external diameter. These dimensions make them easy to transport for camping trips or other off-road adventures.

Efficiency is excellent with the Clean Republic tubes. One tube and an hour in direct sunlight are all it takes to generate hot water from 60°F to 212°F. If used for pump-assisted active heating systems, it increases the input water temperature by 37°F at a 5-gallon/hr flow rate.

That translates to an exceptional water heating rate of 165 Wph, which is twice the other solar panels’ rate. The design of the tube mimics that of a thermos, allowing water to remain heated even overnight.

They may be small, but they’re in no way flimsy. The tubes come with a double-wall structure with vacuums in place between the walls. The inner tubes are super absorbent so that they quickly and efficiently absorb solar energy. The external coating is also coated with copper for infrared-reflective insulation. In addition to copper, the exterior is also made of steel and aluminum materials for a tough, durable build.

In addition to its sturdy materials, the Clean Republic tubes also come with a 10-year warranty. The warranty covers the tubes’ performance, giving you that added confidence when buying.

Finally, the Clean Republic tubes are affordable and actually come out as the cheapest solar water heater on this list. It’s a great option to have if you’re just wanting to test solar water heating.

Perhaps the only downside to the Clean Republic is that it’s too small for larger households. You can definitely use multiple tubes to build a bigger system for a large household. However, you may end up spending the same (or even more) as the larger solar water heating systems.

Overall, the Clean Republic is a great portable hot water solution or for your DIY solar water heating system projects.


  • Versatile in functionality and capacity.
  • Compact and extremely portable.
  • Excellent efficiency.
  • Sturdy and durable built.
  • 10-year performance warranty.
  • Affordable solar water heating solution.


  • It may be too small for larger households.


Our best solar water heater list gives us one important takeaway message: solar water heaters have benefits anyhow and anywhere. Whether you use a dedicated solar water heater or a hybrid one, they provide you with significant savings in the long run. They can also be used at home and in the outdoors, including the sea.

With this in mind, our best of the best solar water heater, therefore, goes to the Heliatos SW-38 kit. It offers flexibility in terms of the essential features of capacity and size and is packed with amazing features. It’s the most versatile and affordable solar solution for your hot water heating needs.

If you’re on a tight budget, the DIY water heater is also a good idea.

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