What is the most efficient solar hot water system?

Electrical water heaters attribute to a chunk of our electricity bills. Hot water is an essential commodity in our lives but along with a heavy cost, electrical systems are also unreliable especially in the event of a power breakout or shortage. Such a scenario would impede the hot water supply for the household. However, there is a way to reduce costs yet retain unlimited access to hot water. 

That’s where solar water heaters help those looking for a constant supply of hot water for their needs. Solar hot water systems reduce your reliance on the electrical grid by utilizing thermal energy from the sun to heat water. 

This article will explain everything you need to know about solar water heaters, which solar water heater is the most efficient, and recommend three heaters for your home in Orlando. 

How Do Solar Water Heaters Work?

There are two integral components to solar water heaters: 

  1. Storage tank.
  2. Solar Collector.

As the name suggests, the solar collector gathers thermal energy from the sun through a system of intricate tubes. It’s an insulated box and when water passes through its tubes, it transfers heat to the water and stores it in the storage tank.

Some systems also incorporate heat exchangers. Such exchangers heat water that flows through the tank’s copper coils. This exchange takes place when the heat is transferred to the tank and cold water flows into the collector.

Unlike solar panels, solar water heaters don’t convert solar energy to electrical energy. Instead, the sun’s thermal energy directly heats the water without any energy conversion.

Types of Solar Water Heaters


Different types of solar water heaters serve different functions. Hence, we can only judge their efficiency based on what purpose you’re using them for.


For residential purposes, active and passive solar heaters are the most common. Let’s take a look at both of these in detail.

DHW Solar Panel


1. Active Solar Heaters

Active solar heaters have controls and circulating pumps, making them more expensive than others. These are further subdivided into the following:


Direct Systems

Direct circulation systems heat your home’s water supply through the solar collectors and pump it back into the house. They work well if you want hot water on the spot. 


Indirect Systems

Indirect circulation systems use glycol or antifreeze, to transfer heat from the solar collector to your home’s water system. Such systems are efficient for cold climates as they prevent the water from freezing. 


2. Passive Solar Heaters

In contrast to active solar heaters, passive solar heaters do not employ pumps to circulate water. The lack of electrical parts makes them slightly inefficient in comparison to active systems, but also more reliable and cheaper. They are also subdivided into further categories:


3. Thermosiphon Systems

Passive thermosiphon systems rely on the inherent property of water becoming lighter when heated. You can find them at the bottom of most storage tanks in varied climates. Hot water flows to the storage tank through the intricately connected plumbing system. As a result, cold water flows to the tubing at the bottom of the tank, aiding circulation. 


Integrated Systems

Integrated systems or passive integral collector-storage systems make use of metal plates to heat water incrementally before returning it to the main reservoir. They are most efficient in places with plentiful sunshine or where people need hot water mainly during the daytime.

Benefits of the Solar Water Heater

Solar water heaters offer multiple advantages over traditional gas or electric water heaters. Here are a few examples:


More Affordable

According to the Department of Energy, “On average, if you install a solar water heater, your water heating bills should drop 50%–80%. Also, because the sun is free, you're protected from future fuel shortages and price hikes.” [1]


While solar systems incur an initial investment, they end up being more economical in the long run. The reason being that they cut your reliance on the electrical grid, saving a large number of your electricity bills. These savings depend on a few factors like your heater’s energy factor rating and your household’s hot water usage. 


Environmentally friendly

Sunlight is a renewable energy source, meaning it does not pollute the environment and is available in an infinite amount. Electrical power stations mostly rely on fossil fuels like coal. Such fuels harm the environment by releasing toxic gases and are limited. This makes solar energy an eco-friendly option.

Solar Panel

Which Solar Hot Water System is Right for You?

As mentioned earlier, solar hot water systems come in different varieties. There’s no universal approach when we talk about the efficiency of solar hot water systems. What may be considered efficient for one household’s needs may not be up to the mark for another. 


Instead, determining which solar hot water system is the most efficient depends on how you plan on using it. Before deciding upon a particular system, here are some factors you should keep in mind:


Daily Water Requirements

Your average water requirements depend on the size of your household. A 30 to 40-gallon system may be sufficient for a small household. But a larger household may require dual 40 gallon systems or an 80-gallon system. Hence, before deciding upon the capacity of your system, it’s best to get an idea of your average water consumption.


Many solar water heaters come with a storage tank. For large households, a tank is essential because it significantly increases the capacity of hot water each member can use without shortage. 


In contrast, tankless options can work if you’re planning on using your system for camping or seasonal cabins. These systems provide on-demand heating, depending on the weather at the time. They have a capacity of around 5 gallons, which can accommodate one or more quick showers.

Solar Panel Energy Process

Type of Climate

The effect of your local climate on your system’s efficiency cannot be stressed enough. If you live in a hot climate with lots of sunshine, there’s plenty of thermal energy available to heat your water supply.


But if you live in a rainy, cloudy, or cold climate, your system will struggle to produce a consistent amount of energy. And if there’s no sunshine for days at a stretch, you could find yourself without hot water if you haven’t made any alternate arrangements, since, without solar power, there is nothing to power the heater. 

For those in the latter climates, it would be best to install a backup electrical system that runs parallel to your solar water heater. The electrical heaters can work on-demand, meaning you can turn them off when there’s enough sunshine and turn them back on during cloudy days. You can also separately purchase backup electric units as an extra layer of protection.


Furthermore, the climate can also influence the type of solar water heaters that are installed. For tropical climates, active direct systems and passive integrated systems are the most efficient solar hot water systems as they provide hot water quickly, utilizing the area’s sunshine at the time. 


On the other hand, if you live in cold or freezing climates, active indirect systems are the most efficient. That is because they use fluids like glycol and antifreeze to transfer heat to the water, preventing it from freezing.

Do You Want the System to Be Portable?

You can choose a portable solar water heater if you plan on using hot water for activities like camping or hiking. Such systems use a simple solar panel to heat a small quantity of water which is approximately five gallons and come with a durable bag, pump, or hose. Some even come with a temperature gauge so you can monitor the water’s temperature in case it gets too hot. 


However, such systems are best for outdoor purposes. They will not work indoors for households because they have a limited water capacity, and they need direct sunlight to heat the water.


Along with portability, you also have to think about the size. Some solar water heaters weigh around 400 lbs., so you need to make sure your roof can withstand that weight. You may also have more space on your roof than the ground or vice versa. You must decide where to place your system depending on the availability of space.

3 Best Solar Hot Water Systems for Orlando

Based on the aforementioned factors, we have compiled the top three solar hot water systems that would be ideal for your home in Orlando. 


1. Heliatos Hybrid Solar Water Heater Kit

The Heliatos Hybrid Kit comes with four heating panels, a 10W solar panel for powering the pump, a circulation pump, and fittings. Although it contains a set of four panels, you can adjust the capacity of the system according to your household requirements by connecting the panels. 


What sets this kit apart is its hybrid design. You can use this as a solar water heater in itself or connect it to your gas or electric heater. Therefore, if there are some cloudy or rainy days, you’ll still have access to hot water.


Moreover, the Heliatos heater is easy to install. You don’t have to do any soldering as the panels are lightweight and come with brass fittings. Although the heater works best on the roof, you still have the option of installing it wherever you like.


The Healiatos heater will work great in Orlando as there is plenty of sunshine available year-round. However, it’s not freeze-proof, but that’s not a problem in Orlando because it doesn’t snow in that area. Apart from that, the panels are durable and Heliatos offers a one-year standard warranty plus a ten-year leak cover.


Drainback solar water heating diagram photo

2. Sunbank Solar Hot Water System

The Sunbank solar water heater is a passive system with a 40-gallon capacity. The company also offers an 80-gallon capacity if you have a higher water consumption.


What makes this such a great product is that it has high efficiency; it can absorb around 92% to 96% of solar energy thanks to its high-density polyurethane insulation and evacuated tube collector. So, if there’s enough sunlight, seamless access to hot water is guaranteed.


This system is easy to install and maintain, making it ideal for beginners. It comes as a complete system with no detachable parts so it’s easier to assemble. You can install it on the roof or ground, depending on space and access to sunlight. It can also work with your existing gas or electric heaters and comes with a ten-year heat collector warranty.


3. Duda Solar 30 Tube Water Heater Collector

What sets the Duda Tube Heater apart is its flexible configuration. You can find tubes in 15, 20, 25, or 30 configurations. This flexibility allows you to adjust the capacity based on your household requirements. For example, the 15-tube system has a capacity of 0.9 liters while the 30-tube system gives 1.7 liters.


Moreover, the collectors come in a variety of installation options. You can choose the 45-degree option if you have a flat roof or the 37-degree one for a more sloped roof. These solar water heaters also have an efficiency of 93% to 96% and can heat water to 250°F. 


This water system is hailstone resistant, making it suitable for all kinds of climates. Since Orlando does face the occasional storm, your system is guaranteed to stay safe. But you will need to be careful about the water pressure; pressure above 87 psi can damage and malfunction the heater.

What Is The Most Efficient Hot Water System?

Solar water heaters are the most efficient hot water system today. Their efficiency is prevalent because they are dependent on sunshine, which they can harness anytime the sun is out. They are also light on your pocket, reducing water and electricity bills in the long run even if the initial investment is high. 

What Is The Best Solar Water Heating System?

The Heliatos Hybrid Solar Water Heater Kit is the best solar water heating system on the market due to its versatility, flexibility, and easy installation.

What Type Of Hot Water System Is Most Compatible With A Solar Hot Water System?

Hot water cylinder systems and conventional boilers are compatible with a solar hot water system. But if your boiler is a combination one or you don’t have a hot water cylinder, then a solar hot water system may not work. 

What Are The Three Major Types Of Solar Hot Water Systems?

The three major solar hot water systems are flat plate collectors, evacuated tube collectors, and heat pump systems. 

The Final Word

Solar water heaters may be just what you need to cut your energy costs and play a part in saving the environment. To determine which is the most efficient hot water system, you’ll need to check your local climate, average water consumption, and the size of your home. But whatever system you choose, it is guaranteed to give you the best results!

Need more information? Contact Everything Solar for a free quote. Simply call us on: 407-545-3590.


1. Estimating the Cost and Energy Efficiency of a Solar Water Heater | Department of Energy.