Best Solar Water Heating Systems

Best Solar Water Heater Systems

By reducing your reliance on the electrical grid, the industry’s best solar water heater systems can help you to save money and the environment. These innovative systems use thermal energy to heat water and can be used in lieu of traditional gas or electric hot water heaters.

They don’t require costly solar panels or overly technical installation and can be a great first purchase for homeowners looking to try out alternative energy.

Solar water heater systems come in a variety of shapes and sizes. Some can heat your shower to the perfect temperature while others can extend the swimming season by heating your pool. Whatever your needs and level of investment, there’s a solar water heater system out there for you.

6 Solar Water Heating Systems

Best Overall: Duda Solar 200L Active Split System

duda solar 200l active split system
  • Gallons: 53
  • Type: Active (indirect)
  • The High Points: Great for cold climates as it’s winter resistant.
  • The Not-So: May not be great for those who travel frequently.

Duda is known in the solar water heating industry as being a reliable and high-quality brand. They are SRCC-certified and can be used for federal or state tax credits and exemptions, which is a great incentive for on-the-fence homeowners to commit to a solar water heating system.

The 200L Active Split System is great because it allows homeowners to heat their water on the roof or other sun-heavy location and store their water in a protected tank close to where it will be dispensed.

This prevents major heat loss by keeping the water warm even with the ambient air temperature is low. The system also utilizes a single copper heat exchanger coil that’s placed near the upper part of the tank to strategically heat the water as it’s being used, so the cold water at the bottom of the tank can be heated later.

What Do Reviewers Say?

Reviewers are generally happy with the efficiency of the Duda solar water heating system. Using the Duda 20 tube solar collection rack, homeowners have reported that they can heat water quickly with only a few hours of direct sunlight and partial shading.

Others have concerns about the rise in temperature that may occur when the homeowner is away from the system. The expansion tank regulates the excess hot water but it cannot withstand more than a few days. This may be a problem for those who travel frequently during the summer months.

Features & Considerations

Duda Diesel’s popular solar water heater comes in a variety of sizes, but the 200-liter (53 gallon) system is the best for residential use.

Its water tank rivals standard electric or natural gas systems but eliminates the need for costly energy consumption as it’s equipped with a solar water heater collector. The storage tank itself consists of food grade stainless steel.

It also includes an 8-liter expansion tank to help prevent failures in the system due to stagnation. This means your solar collectors won’t be damaged if the amount of solar energy exceeds the amount of water you’re heating at any given time. There’s also a thermostatic mixing valve to prevent scalding.

The solar collector is fitted with twenty 14mm solar tubes on a 45-degree stand, which can easily be exchanged for a 37-degree or slope roof stand if you plan on mounting it elsewhere.

The solar collector transfers the heat of the sun to your water pump through an indirect circulation system. The Duda kit includes the necessary two gallons of food-grade inhibited propylene glycol used in the process.

The kit also includes a solar water heater working station which regulates the split pressurized system by connecting the collectors, storage tanks, relays and sensors. It uses a circulation pump, pressure gauge, pressure relief valve and check valve.

Other safety systems include an automatic air vent for purging air from the top portion of the system, and a submersible water pump for the initial air purge and charging of fluid into the system.

Runner-Up: Sunbank 40 Gallon Solar Water Heater

sunbank 40 gallon solar water heater
  • Gallons: 40
  • Type: Passive (thermosyphon)
  • The High Points: Requires virtually no maintenance.
  • The Not-So: Not as efficient as an active system.

The Sunbank 40-gallon solar water heater is a no-frills integrated system that can be easily installed and maintained by any homeowner.

The passive water heating is great for small households living in mild climates that receive a lot of sunlight. With no-moving parts or extra pieces, the Sunbank system is a great starter kit for those who may be intimidated by more intricate and advanced solar heaters.

With a SRCC certification, the Sunbank is a cost-efficient way to cut down on expenses. Their affordable price point and 10-year warranty guarantee financial security. By using a passive solar system, homeowners can save as much as $600 per year in energy costs.

What Do Reviewers Say?

Most reviewers are pleased with their Sunbank systems as they are efficient and reliable. One reviewer even claimed that the water is too hot. In general, homeowners have been able to easily assemble and install the systems on their own.

However, several homeowners have purchased dual 40-gallon systems to increase the capacity of their hot water tanks as a single system is not enough to service an entire family.

When buyers had concerns about their water intake or configuration, the Sunbank staff were eager to assist and advice on the best setup. For those DIYers with a big household, a dual Sunbank system may be the best option.

Features & Considerations

The Sunbank system includes a tank, evacuated tube collectors and bracket. The 40-gallon tank is made with stainless steel.

The high-density polyurethane insulation also provides heat retention to prevent extra heat loss in low ambient temperatures. The size of the tank is adequate for small households of one to three people. Those with larger families may want to consider an 80-gallon tank instead.

Sunbank’s system is passive, rather than active, so it doesn’t require pumps, glycol heating fluid, or any moving parts. This makes installation much more convenient for novice plumbers or DIY homeowners.

Passive systems are also cheaper than their active counterparts and are a great “starting point” for those looking to enter the solar market.

Since the system doesn’t use pumps, it’s pressurized. The system relies on municipal or well water pressure to move the water in and out of the tank. Once a faucet is turned on, the cold water is pushed into the hot water tank, which then pushes the hot water to your faucet.

The 15 evacuated solar tube collectors are mounted on a corrosive resistant aluminum bracket. Each tube can collect 92-96% of the sun’s energy in prime conditions.

The tubes can be used as a pre-heater for an existing system or as a stand-alone unit. They are best suited for roofs that receive an adequate amount of sunlight.

Best for Camping: Sportneer Solar Shower Bag

sportneer solar shower bag
  • Gallons: 5
  • Type: Panels
  • The High Points: Allows for temperature control.
  • The Not-So: Can only provide enough hot water for a few short showers.

As far as portable showering is concerned, Sportneer’s Solar Shower Bag ticks all the boxes. With a durable design and host of features, campers can now have a hot shower even in the wilderness. However, this bag is not a substitute for indoor showering or advanced solar water heating systems.

The design of the Sportneer is simple: a small, integrated solar panel heats up the water which is held in an insulated PVC bag. With a 5-gallon capacity, the bag can provide enough showers for a solo outdoorsman or a small crew. It also comes equipped with a temperature bar, shower head, storage pockets and a carrying case.

What Do Reviewers Say?

Buyers are pleased with the convenience the Sportneer Solar Shower Bag provides. They claim that it’s great for camping or outdoor activities as it’s portable and durable. One complaint that seems to be common among buyers is that the shower head is too small.

Some have tried unsuccessfully to use it as an at-home product, but it is not really a suitable alternative for a normal shower. However, some use it as a backup for power outages or other emergency situations.

Features & Considerations

The Sportneer Solar Shower Bag is the perfect accessory for avid campers. The bag is made of durable PVC material and comes with a hook for temporary installation on a tree, wall or car.

On the front of the bag are two net pockets that can be used to store bath products. It only weighs 1.2 pounds and can be easily rolled up and stowed in its mesh carrying case during outdoor excursions.

With a built-in solar panel, the shower bag can heat water in direct sunlight in as little as 3 hours. It includes a temperature indicator on the back so campers can add cool water if the bag exceeds comfortable levels. With a 5-gallon capacity, the bag can hold enough hot water to last a few short showers.

Attached to the bag is a shower hose with nozzle that simulates a real shower experience. The hose is connected to a water inlet with a sealed cap to prevent leakage. If the hose does manage to leak, the kit includes cable ties that can be used to prevent further leaks by closing off the connections.

Best for Swimming Pools: SunQuest 3-2X20 Solar Swimming Pool Heater

sunquest 3 2x20 solar swimming pool heater
  • Gallons: N/A
  • Type: Flat-plate (unglazed)
  • The High Points: Can raise the temperature of a swimming pool by up to 10 degrees.
  • The Not-So: Can’t be used for residential purposes.

The SunQuest Solar Swimming Pool Heater is a great option for those with a pool at home. During off-seasons, like spring or fall, the SunQuest can keep your pool at a comfortable and ambient temperature. With a maximum 10 degree increase in temperature, you can swim at any time of year.

The system works by pumping the water through unglazed tubes that heat the water before it’s returned to the pool. It requires very little installation or maintenance and can be used for above or below ground pools. Even better, the sleek black heating pad won’t be an eyesore in the back garden.

What Do Reviewers Say?

Buyers are happy with the effectiveness of the heater. A standard pool pump works well with the system. However, the pool will not be very warm during cloudy days or cool nights.

One note is that a pool skimmer will not work properly when you use both at once. It’s a good idea to use a diverter valve to bypass the heater while the filtration system is operating. Overall, the system is a great value and can help to extend swimming season for the family.

Features & Considerations

The SunQuest system is unique in that it heats both in-ground and above-ground pools through an integrated unit. It works with the pool’s pump to push water through the heated coils and back into the pool, raising the temperature by up to 10 degrees.

It’s a very cost-effective way of extending the swimming season when spring or fall temperatures drop below comfortable levels.

The kit comes with two 2 by 20-ft. panels that you can simply place on the ground or a rack near the pool. The system is UV protected and won’t be damaged by the sun. It also comes with a “MAX-FLOW” design that improves the water circulation.

You will need to purchase additional piping to complete the installation. This will connect from your pool to the heating pads. The system comes with standard connectors to attach to flexible or rigid pipes and hoses.

Best for Off-Grid Cabins: Clean Republic Heat Streamer

clean republic heat streamer
  • Gallons: 5
  • Type: Passive (integral)
  • The High Points: The system is very cheap and easy to use.
  • The Not-So: It will only heat very small batches of water at a time.

The Clean Republic Heat Streamer is not a hugely popular option, but it’s certainly effective. For those looking to toe-dip in solar water heating, this system is for you.

With a small array of solar tube collectors, the integral passive solar heating system can warm up to 5 gallons at a time.

The small capacity and easy installation of the Heat Streamer is perfect for those who have an off-grid cabin. You can use the system to boil water for cooking (or, perhaps look into a solar oven), showers or general heating. However, it’s not the best option for those living in an average-sized household with more than one person.

What Do Reviewers Say?

Overall, buyers are happy with the Clean Republic Heat Streamer. While it’s not a fancy or high capacity system, you get what you pay for. Some buyers have used it for thermo projects while others have installed them in hunting cabins or to heat pools.

One buyer was not happy with how the tubes fit into the frames. The frame fails to cover the top of the tubes which will lead to rain damage if you install it outside in inclement weather. The buyer circumvented this issue by purchasing weather stripping.

Features & Considerations

While 5 gallons is not much water, you can expand the system by including more units. It’s great for cabins or bunkers that you use infrequently for light showering or kettle boiling. You can heat the water in as few as 4 hours if used with their solar water heater pump.

The tubes heat water at a rate of 165 watts. If can increase the temperature of input water by 37 degrees if the water is being circulated at a flow rate of 5 gallons per hour. Each unit is made of copper manifold pipes with continuous u-bends, minimizing space and maximizing efficiency.

The system can handle up to 100psi, which is suitable for most city supply water. However, closed systems, like those used in remote locations, must be installed with a relief valve. Overall, installation is fairly painless and requires little assembly.

Best All-In-One Kit: Northern Lights Group SWH-1 Solar Hot Water Heating Package

northern lights group swh 1 solar hot water heating package
  • Gallons: 50
  • Type: Active (indirect)
  • The High Points: Includes everything you need to set up an advanced residential solar water heating system on your own.
  • The Not-So: It is quite expensive compared to other kits.

As the most comprehensive kit on the market, the Northern Lights Group SWH-1 package really has it all. It provides every bit and bob necessary for DIY installation, which saves money and resources. Not only that, but each product is of great quality and offers a host of features and functions.

One of the highlights is the controller that allows for heating of two separate zones. This means you can heat your water tank for showers while also providing heat to a swimming pool. And should the weather fail you, the tank comes with a 4.5Kw back-up electric heating element so you’ll always have access to hot water.

What Do Reviewers Say?

Unfortunately, there are no direct consumer reviews for this kit. The kit also includes a number of different brands.

While each product is of high quality, it’s still important to first check your specifications and consult a local expert if you have questions before purchasing.

Features & Considerations

This solar water heating kit includes everything you need to set up an advanced residential system without a solar installation company. The kit includes various products of brands, including SolarStor, SunRain, RESOL, Aurora, Spirotech and more. However, the Northern Lights Group compiles and certifies the kit, which is a company that provides solar solutions for DIY homeowners.

The solar heating package can service a family of four and doesn’t require any complex installation like soldering or electrical wiring. It also includes a RESOL DeltaSol Bs+ controller that allows for optional heating of a secondary zone, like a pool, hot tub, or furnace. This is a huge bonus for homeowners.

SunRain’s TZ-58 1900 30R vacuum tube collector heats the 18 liters of ProSol LH-T fluid that comes with it, which then transfers to a 50-gallon SolarStor tank.

The tank has a built-in heat exchanger with a 4.5Kw backup heating element that’s UL and CSA certified. For safety, there’s an 18-liter high temp solar Zilmet expansion tank and a Spirotech AutoClose solar air vent.

The kit also includes a RESOL FlowSol solar pump station, Aurora Solar Flex steel piping that’s pre-insulated and weather proofed, and a complete manual for installation. The company offers free technical support if you encounter challenges during installation. Overall, this is one of the most comprehensive kits on the market.

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The Complete Solar Water Heating Systems Buyer’s Guide

What to Look for in a Solar Water Heater System

There a bunch of different types of solar water heater systems available on the market so choosing the right model can be daunting. However, each system is specifically for a specific task, whether that be heating a pool or providing hot water for showers. After figuring out your needs, it’s relatively easy to find the right model that will provide you with hot water all year-round.

What type of climate do you live in?

As with other solar products, the local climate effects the efficiency of your unit. Those who live in cloudy, rainy or cold climates will have a harder time producing a consistent amount of energy. During particularly dreary periods, this could mean regular cold showers — a situation most homeowners want to avoid.

If you don’t want to run out of hot water, you should install a backup electric system in parallel with your solar system. You can turn these “point-of-use” electric heaters off when there’s sun and use them only when there’s a lack of energy production. Some kits include these backup electric units, but you will need to purchase them separately.

The type of solar water heater you purchase will also depend on your climate. Some types, like active direct circulation systems and passive integral collector-storage systems, won’t work properly in freezing weather. You should only use them in tropical climates.

If you live in a particularly cold area that’s prone to freezing, an active indirect circulation system is the best option. This system pumps heat transfer fluid through the solar collectors which prevents freezing. These are some of the most popular, and most expensive, options on the market.

How much water do you need?

In general, the amount of water you’ll need is determined by your household size. Those with smaller households will only need a 30- to 40-gallon system. However, those with bigger families will need an 80-gallon system, or dual 40-gallon units.

Most solar water heating systems come with a storage tank. However, some only provide on-demand water heating that’s dependent on the weather at the time. These systems are lower capacity as they can only heat as much water as can fit in the solar collector tubes.

For those living in a multi-person household, a storage tank is essential. If you plan on using your system in a small seasonal cabin or for camping, a tankless option is just fine. These systems usually offer 5 gallons of water, which is enough for a quick shower or two.

Do you want to heat a swimming pool?

Pool water heating systems operate quite differently from residential systems. In fact, they are completely different products.

However, some solar water heating systems are “hybrid” and offer both residential heating and pool heating. There are also kits that include controllers that can direct hot water to two separate systems, like a storage tank and a hot tub.

In general, solar water heating systems specifically for swimming pools include with flat-plate collectors. There are two different types of flat-plate collectors: glazed and unglazed.

Pool systems are usually unglazed as they are cheaper to make. However, they don’t have any enclosures so you should protect them from inclement weather as they can easily get damage.

You can install solar pool heaters on the ground, on a rack or on the roof. In general, the surface area of the solar collector should be equal to 50-100% of the surface area of the pool.

You will also need to connect it to a standard pool pump that will push the water through the heated tubes and back into the pool. You’ll need to assess the size of your pool and access to sunlight in your yard before deciding on the right model for you.

Does the system need to be portable?

You do not need to install all solar water heater systems or wire them to sensors. In fact, there are a number of portable solar water heaters that use a simple solar panel to heat a small amount of water. These models are perfect for campers, hikers or outdoors enthusiasts who want access to a hot shower in the wilderness.

Portable water heaters include of a durable bag, a hose or pump and a solar panel. You’ll want to find an option with a temperature gauge to prevent against accidental burning. Shower heads and proper hoses are also great features as they simulate a real shower.

Most portable showers are small and can’t hold more than a few gallons of water. However, a 5-gallon model can provide enough water for several hot showers if you’re quick. It’s important to note that these are not suitable for indoor use as the solar panels can’t access the sun and they have a limited water capacity.

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Selection Criteria: How We Ranked the Best Solar Water Heater Systems

Based on our specified criteria, we’ve narrowed down a competitive list of options to feature the 6 best solar water heater systems.

Our rankings specifically focus on the capacity of the water heater (in gallons) and the type solar collection. It also takes into consideration the quality and extra features of the overall system.

Gallons

The required capacity of a solar water heating system is generally determined by household size. The capacity of a water heating system is measured in gallons or liters.

Family size averages:

  • 1-2 people: 30 gallons
  • 2-3 people: 40 gallons
  • 3-4 people: 50 gallons
  • 5 or more people: 80 gallons

Type

There are several different types of solar water heating systems. The two main types for residential use are active and passive.

Active systems have circulating pumps and controls and are generally more expensive. Passive systems are not as efficient as active systems but can be more reliable. However, there are other options, like portable panels and flat-plates.

  • Active direct circulation systems pump water through the solar collectors to warm it and then back into the house. They are good for warm climates and on-the-spot heating.
  • Active indirect circulation systems use a fluid, like glycol, to transfer heat from the solar collector to your water supply. They are good for very cold climates and storing water away from the collection zone.
  • Passive integral collector-storage systems use metal plates to heat small amounts water before returning it to the storage tank. They are good for warm climates and day-time water use.
  • Passive thermosiphon systems are installed below a storage tank and allow the warm water to rise above the cool water. They are good for long-term residential use in varied climates.
  • Flat-plate glazed systems are made with copper tubing on a metal plate with a glass covering and use heat exchangers and transfer fluid. They are good for heating swimming pools in cold climates.
  • Flat-plate unglazed systems are made with copper tubing on a metal plate mounted on heavy-duty rubber with no enclosure. They are good for cheaply heating swimming pools during specific seasons.
  • Panel systems use a small watt solar panel to heat the water in a stagnant position. They are good for hot showers while camping.
Solar Water Heating Systems Type of System
Duda Solar 200L Active Split System Active (indirect)
Sunbank 40 Gallon Solar Water Heater Passive (thermosiphon)
Sportneer Solar Shower Bag Panel
SunQuest 3-2X20 Solar Swimming Pool Heater Flat-plate (unglazed)
Clean Republic Heat Streamer Passive (integral)
Northern Lights Group SWH-1 Solar Hot Water Heating Package Active (indirect)

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Frequently Asked Questions (FAQ)

How do solar water heaters work?

Solar water heaters have two primary parts: a solar collector and a storage tank. The solar collector is usually an insulated box with a bunch of tubes that turns the sun’s energy into heat. When the water passes through the tubes, the tank heats and stores it.

Some systems use a heat exchanger which heats up a water or another fluid which then flows through copper coils in the tank. The heat moves on to the tank and the water that has cooled returns to the collector.

Each version of a solar water heater works because of thermal energy. This is different from standard solar panels because it doesn’t turn the sun’s radiation into electricity before heating the water. Instead, the sun directly heats the water and circumvents the need to convert energy to electricity to heat.

Do I need to connect to a solar panel grid?

Because the solar water heater systems use thermal energy rather than electricity, they don’t connect to the grid. In fact, there are not any solar panels as part of the process (unless it’s a portable version). You can use your solar water heating system without solar panels or in conjunction with a solar array.

However, if you’re looking to use an electric water heater rather than a thermal model, then you’ll need to hook up to a solar panel. These appliances are the same sort that you’d connect to the standard municipal grid and people don’t consider them to be “solar water heaters”.

Will I need to purchase a tank or additional equipment?

Most systems are not all-inclusive and will require some additional resources, like piping, connectors, tanks or other items. There are a few comprehensive kits on the market, but most offer just the basics.

If you’d like to expand your system, have more control over it, or connect it to a particular source (like a pool), then you’ll need to purchase more equipment.

Can I still get hot water when it’s cloudy?

For the most part, solar energy systems only operate at peak efficiency during sunny days. When there’s inclement weather, such as a lot of cloud coverage, there may not be enough energy to harvest, leaving you without hot water. In this case, having a two-tank system is beneficial because it can store hot water for several days.

Other green options include purchasing a small electric water heater. You can connect these to a solar grid and used when there’s not enough hot water. If you have excess solar energy in your batteries, you can use that to temporarily power an electric water heater when it isn’t producing thermal energy.

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Mariah Grimwood

About Mariah Grimwood

Mariah Grimwood has been producing web content for two years and counting, with an extra special focus on things she's passionate about: eco-friendly options, travel and education. With her knack for research and eye for unsightly syntax, she's on a mission to revitalize informational resources for online readers.