What Is A Solar Water Heater

Are you searching for a detailed explanation of what a solar water heater is all about? You’ve come to the right place.

A solar water heater can be more expensive than the traditional water heaters, the solar energy you’ll use can save you money and help your environment.

For your home energy consumption, water heating accounts for 18%, meanwhile, solar water can reduce your heating costs by 50 to 80%.

I’ll give you an in-depth explanation of how solar-powered water can help you tap into a free, renewable energy source while saving you money in this article.

You can choose if a solar water heater is a good investment for your home’s hot water requirements with this knowledge.

Solar Water Heater; Basics Explanation

Solar Water Heater; Basics Explanation

The function of a solar water heater is to heat water or a heat-exchanging liquid by exposing it to the sun’s rays, then pump the warm liquid back into your home for domestic use.

A storage tank and a collector to trap the sun’s heat are the basic components of all solar water heaters.

Also, a set of flat plates, tubes, or tanks that move water or a heat transfer fluid through and absorb the sun’s heat makes up the collectors.

Furthermore, the fluid pumps to a water tank or a heat exchange unit.

Before it enters a home’s traditional water heater, you can use solar water heaters as energy-saving devices to warm water.

How then does the solar water heater work? Let’s find out.

How Solar Water Heater Works

How Solar Water Heater Works

A garden hose left out in the sun is an example of solar water heating at its simplest level. A garden hose is a transfer pump used in transporting water for gardening or cleaning any vehicles.

However, the first water that comes out of the garden hose when you turn on the spigot is warm because it’s been heating in the sun.

Similarly, a solar water collector operates the same way. In a solar collector, water flow through tubes.

Furthermore, a sensor measures the temperature difference between the water in the storage tank and the water in the collector throughout the day.

The sensor triggers a pump to move through the collectors, where it collects heat when it meets a specific temperature difference.

All your household demands during the summer months, your solar water heater can meet it all.

This system can cover up to 85% of your hot water needs for a year.

Finally, you can look into any tax credits or rebates that are available in your area to save you money on your initial purchase.

You will need to know that there are kinds of solar water heaters. In case you would want to know their differences, please read further.

Types Of Solar Water Heaters

Types Of Solar Water Heaters

The open-loop and the closed-loop systems are the various types of solar water heaters we have.

Drainback Solar Water Heating System

The heat transfer fluid uses filtered water. Also, for the collector loop, it flows through it and serves as a medium.

Furthermore, with the help of the pump, the water flows through the collectors. It is a non-pressurized system.

Water flows through gravity to the heat exchanger and storage tank. The system shuts down when the pumps are not running.

Additionally, if the water in the storage tank gets too hot, it has a feature that shuts off the system.

Plus, it requires an extensive piping system for the Drainback Solar Water Heating System for installation.

Finally, it does not require any check valves, air vents, or pressure gauges because it is more convenient.

Active Open Loop Solar Water Heating System

This system works on the principle of heat transfer through the water at a constant pressure since it is a low-cost device.

At the base of the storage tank is a temperature controller for the system. The mechanical controller activates the moving pump when the water in the storage tank is cold.

Furthermore, it gets heated and returns to the tank’s top since water is drawn from the storage tank to the solar collector.

Passive Solar Water Heating System

Firstly, it requires a storage tank on the top as well as an installation on the rooftop.

Secondly, this system contains a collector that collects cold water from the city’s water supply.

The water gets heated in this collector. It will remain there for the rest of the day until you use it since the heated water flows to a storage tank.

During this time of storage, the risks of heat loss are higher. The version of this technology that stores water in an insulated tank is the thermosyphon system.

Active Closed Loop Solar Water Heating System

Firstly, the heat transfer fluid (HTF) runs through the heat exchanger and the collector uses the water heating system.

It helps in transferring heat to the stored water in the tanks since the heat transfer fluid is non-toxic.

The HTF that requires replacement every 3-10 years is the glycol which is in most of the systems.

Plus, the collector is continually under pressure because this system is a little difficult.

Solar Collectors With Evacuated Tubes

In this system, transparent glass tubes are placed parallel to each other.

Inside these tubes, it uses a metal absorber tube with a fin. Also, in the absorption of solar energy, the fin’s surface has a coating that helps.

This method is mostly used for business purposes. The newest version of this system includes tempered glass cover plates.

Lastly, using these plates improves the durability of the heater.

How did the solar water heater become a constructive element or instrument? The only way to find out is to read the next subheading.

Construction Of Solar Water Heater

Solar water heaters are easy to design. The key components of a solar water heater include a heat transfer system, solar collector, heat transfer fluid, pressure valve, piping. etc.

Solar Collector

The solar heater that helps to capture and transfer the sun’s energy into heat, is the solar collector.

In essence, it contains a black metal plate that helps to absorb as much heat as possible.

The fluid that gets heated is stored in pipes beneath this plate. The metal plate connects to all of these.

Finally, as it passes through these pipes the fluid is heated.

Storage Tank

The insulation in the storage tank may or may not be present. This helps in the storage of water that has been heated by the heat transfer process.

Also, it has a cold water intake at the bottom and a heated water outlet at the top.

However, the fluid which gets heated is stored in pipes below this plate and the metal plate links to all of the pipes.

Plus, as it passes through these pipes, the heat transfer fluid gets heated. The heat transfer system is installed in the tank.

Heat Transfer System

The tubing in this arrangement carries the heat transfer fluid. It heats up when it flows through the solar collector.

Plus, within the storage tank, the heated fluid runs through the pipes to the heat transfer system.

Pressure Valve and Air Vent

An air vent and a pressure valve are also on the storage tank. In the case of overpressure which steam or air generates, the pressure valve adjusts the pressure within the tank and helps in air escape.

What are the factors you need to consider when buying a solar water heater? Read the analyses below.

Factors To Consider While Buying Solar Water Heater

Factors To Consider While Buying Solar Water Heater

Purpose or Use

Firstly, solar water heaters are the way to go if you own a large business and need water heaters for your office building.

Also, you’ll recover your investment quickly because they will help you save a lot of money on electricity.

Moreover, you’ll need to purchase a high-efficiency solar water heater otherwise, you may start experiencing cold water after only a few uses.

Don’t buy a solar water heater if you live in a tropical area where the use of water heaters is rare.

In comparison to electric water heaters, they are quite expensive. You won’t be able to recover your investment.


Solar water heaters are available at various prices. In comparison, they are more expensive than electric water heaters.

Also, solar water heaters have an upfront cost because they will help you save money on electricity.

If you feel you’ll be using a solar water heater for a long time then go for it if you are a permanent resident of a place.


There are types of heating systems for solar water heaters. Under this types, there you have;

Evacuated Tube Collector (ETC)

This system is made of glass so it is prone to damage because the evacuated tube collector is less expensive.

Plus, you will need to use a heat exchanger to safeguard the heating capability of this system if your water supply is salty.

Flat Plate Collector (FPC)

This system costs a lot of money and it consists of metal. This solar water heater is more reliable and has a longer duration.

You may need to use costly anti-freeze chemicals to keep this system safe if you use a flat plate collector in an area where the temperature drops below zero.

Size and Capacity

Solar water heaters that are large are quite pricey. Nevertheless, they function well at the same time.

You should buy a large one instead of buying two small ones if you want to use solar water heaters frequently.


An excellent solar water heater can withstand one or two cloudy days, but not more. Thereafter, it will give you cold water.

You have two options if you want to avoid this. It’s either you get a solar water heater that runs on electricity or you keep a spare electric water heater ready for emergencies.

Geographic Location

The amount of sunshine that your solar water heater receives directly affects its heating.

If you live in a place close to the equator, it will be effective. Notwithstanding, its heating capacity decreases quickly as you get closer to it.


Make sure you buy a reputable brand because there are a lot of less expensive solar water heaters on the market.

Reputable brands are more reliable and provide superior service. Take note of fake brands.


A warranty provides further assurance that the product you are purchasing will last.

Go for it if you come across a great branded solar water heater with a long warranty duration.


For such products, most countries have a certification standard. Therefore, double-check that the product you are purchasing has the certification of national or regional standards.

That is the end of what you need to know before considering a solar water heater. They are very essential and you need to take cognizant of them.

Moreover, as you have seen what to put into consideration, you still need to know what it is used for.

Uses of Solar Water Heater

Uses of Solar Water Heater

For various applications, the solar water heater is the ideal option that is available. The various place you can use a solar water heater are:

Domestic Use

You can use a solar water heater in your home applications to heat water in apartments, flats, and bungalows.

Commercial Use

You can use solar water heaters in commercial places such as hostels, hotels, hospitals, and dormitories.

Industrial Use

Solar water heaters are used in many industries. This system is used in companies that require hot water for various purposes such as washing, preheating, and even other operations.

Pros and Cons

Pros and Cons of Solar water Heater

Once you start heating your water under the sun, it is one of the ways to take advantage of solar renewable energy without stress. Even with that, there are still disadvantages surrounding it.


Here are some top advantages of using a solar water heater.


When it comes to heating water, one of the many reasons solar panels outshines other kinds of energy is the efficiency they provide.

Simply put, solar panels convert nearly all of the sunlight into heat energy without using external fuels. Hence, you will be using a solar water heater efficiently.


In essence, energy from the sun is what solar panel uses. It simply means you won’t pay a dime to the power system for the electricity you use.

Also, it is available and free daily use since it is a renewable source of energy.

Find out how to adjust the solar panel’s performance on cloudy days because that’s all you need to do.

That is to say, once you have a solar panel there will be no extra cost of using a solar water heater.

Saves Space

For the installation of a solar water heater, you don’t need to bother yourself about the availability of space.

Save For Environment

A solar water heater is the most environmentally friendly source available for heating up your water. They don’t rely on fossil fuels, emit no pollution, and have smaller carbon footprints.

Installation is cheap

Firstly, installing a solar water heater is much less expensive than installing a photovoltaic (PV) panel.

Secondly, the ideal method in receiving awards is by transferring the surplus unit back to the electricity grid.

Plus, it will payout in the long run because it is a one-time investment.


  • It stores hot water that you can use at night if your storage tank is sufficiently insulated because it heats only during the day.
  • In essence, solar water heaters rely on the availability and abundance of direct sunlight to work.
  • Also, you’ll need more roof space for the installation of a solar water heater.
  • In rainy seasons, foggy, or cloudy days, it won’t be helpful to you.
  • Bear in mind, you’ll have to check the pump and antifreeze once a year.

If you are wondering how to know the best solar water heater that will be suitable for your home, worry less. Here is the top best product you can choose from the amazon website.

My Recommendations; 5 Best Picks

Duda Solar 200 Liter Water Heater

In the solar water heating area, Duda is known for being a dependable and high-quality brand.

Also, it allows you to heat water on your roof or in a sunny place, then store it in a covered tank near where it can be supplied.

Furthermore, it keeps the water warm even when the air temperature is low, which prevents a major heat loss.

Additionally, a single copper heat exchanger coil near the upper section of the tank is used to heat the water as you use items.

To prevent system failures that stagnation causes, it comes with an 8-liter expansion tank.

Simply put, if the amount of solar energy you receive at a particular time surpasses the amount of water you are heating, it won’t damage your solar collectors.

Finally, just to avoid scalding, it comes with a thermostatic mixing valve.

Sunbank 40 Gallon Solar Water Heater

A passive solar water heating system that is simple to install, efficient, and less expensive is Sunbank’s 40-gallon solar water heater.

This product qualifies for both the federal tax credit and local benefits for solar water heaters because it is SRCC certified.

Also, an attractive feature that differentiates Sunbank from its counterparts is the 316L stainless steel tank.

The installation costs make up the majority of the total cost, therefore I want you to use this product for a long time.

Additionally, this brand provides you with a highly corrosion-resistant aluminum and stainless steel bracket.

You can use this system as a pre-heater to your existing system because of its built-in 240V-2400W heating element and control device.

Overall, Sunbank has a standard 10-year collector warranty and a one-year warranty on all other system parts.

Duda Solar 180 Liter SUS304 Passive Water Heater

Another solar water heater manufactured by Duda energy to be used for domestic water supply. The tank can carry up to 180 liters of passive water.

The water is supplied from the well water, which then transfers directly to the plumbing water in the building for later use. This effect takes place because of the electric backup water heater and the TK-7Y controller.

However, the passive water heater controller enables the timing of the backup water heating display and the temperatures of the tank. With that, you can prevent unnecessary wastage of hot water when you are not in need of it.

Hence, the need to employ the use of the electric backup which sets the time and prevents excess waste of hot water. This in turn gives room for the sun to replenish heat.

Furthermore, once sunlight penetrates the tubes, it performs up to 96% efficiently.

Not only that, this design is a 304 stainless steel shell made to stand any weather including winter. That is why it features hailstone resistance and winter resistance, working on the maximum operating speed of 100 per second.

Therefore, you can use this Duda product in any application in the southern region. But not applicable in the northern region.

For instance, in a northern region where freezing is common, it is advisable you use a split active water heater system instead of the passive solar water heater.

Lastly, Duda energy says this passive water heater has a lifespan of 15 years, which is up to 70% guaranteed to use this solar water heater in your home.

Duda Solar 30 Tube Water Heater Collector

From the look of things, you will discover that Duda happens to be one of the best industries producing the best solar water heaters. They manufacture different solar water heaters with several tubes ranging from 20 – 1000 tubes.

This particular product operates in a 45-degree frame evacuated vacuum tube. Plus, it is certified by the SRCC, meaning that this product is licensed and has passed its usage test, and is eligible to use.

Also, it passes the 305 federal tax rebate.

However, the evacuated vacuum tube retains heat more than the flat panel tube. Thus, it operates much better in cold weather.

That makes it the most efficient water collector in the market. More so, it has winter and Hailstone resistance.

Lastly, it features copper heat pipes, manifold insulation, rockwood, and they are all rated as the best heat retainer.

Duda Solar 200 Liter Water Heater Active Split System Dual Coil 

This is another 200-liter water heater, a replica of the 200-liter single coil but this is a dual coil. You can use this in a freezing environment like the northern region.

Therefore, it falls under the categories of close loop system also certified by SRCC with the 30% government tax rebate.

Apparently, this solar water heater features other collectors such as the water heater storage tank. The storage tank covers the circulation pump, controller, expansion tank, pressure gauge, pressure relief valve, and many more.

Also, it features a thermostat mixing valve for the prevention of scalding. Again, there is an automatic air vent for the purging of air from other uppermost parts of the device.

Finally, the included submersible water pump is for initial charging or air purging of fluid into the system.

And that is the end of my discussion on this solar water heater. I believe after going through the above product and its features, you will be able to make a decision according to your budget.

My Summary; What Is A Solar Water Heater?

Solar water heaters are more pricey upfront, but they are always the perfect choice for heating water.

Furthermore, the proper amount of solar panels to suit your home’s heating requirements is the only thing you have to keep in mind.

Also, with the help of solar collectors on your roof, solar water heaters use solar energy to heat water.

Additionally, a pump moves hot water from the solar collectors to your home in an active solar water heater.

Plus, instead of using pumps, it uses convection to move the water in a passive solar water heater.

I hope you found this PowerVersity pick helpful?

If you found it helpful, kindly share your thoughts with the “Leave a Reply” form found towards the end of this page.

Finally, you may want to read other articles like this. Visit our below pages.

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Akpan Iniobong
Akpan Iniobong is a Technical Writer for PowerVersity.com. She has a B.A in Religious Studies. She loves hiking, reading, and socializing. In PowerVersity.com, she writes buying guides and product best picks.
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