Solar Water Heaters Vs. Solar Energy Systems – Are they worth it?

For homeowners who want to decrease their energy costs, installing solar water heaters is a common way of doing so. In addition to providing large amounts of hot water, these Solar Water Heaters minimize the use of dirty fossil fuels like natural gas/coal and use solar/renewable energy. The best part of using solar water heaters is that they can be used in any climate as long as there is sunshine.

This article digs deeper into how solar water heaters operate, and also most importantly, demonstrates how much money you can save by switching to solar water heating systems.

What is a solar water heater?

The Solar water heating system was first developed and patented in the late 1800s[1]. It had become a staple for most households within five years. The industry suffered a significant decline cause of copper shortages during World War II and crippled the entire industry. The solar hot water systems were prevalent because they enable you to reduce your power cost while also heating your water using environmentally friendly energy sources. The solar water heaters are only responsible for heat water. They do produce any solar electric energy for your residence. They are solar collectors and not solar panel devices that can generate electricity.

Solar water heaters or otherwise called solar domestic hot water systems, in contrast to conventional water heaters, do not need any electricity to heat the water. Instead, these high-efficiency appliances take the sun’s energy via the use of a specialized solar collector or collectors installed on your roof. It is then possible to utilize the solar energy that has been gathered to heat the water in your house.

In recent years, people have increasingly turned to electric heat pump water heaters, which are often used in conjunction with residential solar panel systems. The power used by electric heat pumps to heat your water comes from the grid. When combined with a home solar system, they can still operate on solar electricity.

In cases when you are unable to build a complete house solar system, or if you live in an off-grid home, a standalone solar water heater may be an excellent alternative.

Solar water heaters or a Home solar energy system?

Solar water heaters are indeed a popular choice for many people. Still, times have changed because the current tendency is for homeowners to install a solar panel system on their property. And it’s primarily because the cost of solar panels has decreased significantly in recent years. For cost-effectiveness, pairing a home solar panel system with an electric water heater is the best choice. Not only will the solar panel system cover your hot water expenses, but it will also cover the energy costs of your whole house.

Solar water heaters, on the other hand, may be beneficial in some situations. Compared to solar panels, they are more effective at their particular purpose, which is water heating. The sunshine must heat only the water; it does not need to be converted into energy and power a system to heat it.

The installation of a solar water heater takes up much less roof space than a complete solar system. Solar hot water heaters may be the ideal option for you if you have limited space and want to maximize the benefits of solar energy.

How do solar water heaters work?

A solar water heating system can produce enough hot water to meet most of your household’s daily hot water requirements.

There are two primary kinds of solar water heaters available:

1. Active Solar Water Heater

2. Passive Solar Water Heater

Each of them functions differently and is comprised of various pieces of equipment. 

Active solar water heaters

Active solar water heaters require a pump to move hot water from the solar collectors or absorbers to the rest of the house. These are often seen in colder regions since the water is pumped into a storage tank that can be kept inside to avoid freezing during the winter.

Dynamic solar water heaters are available in two distinct configurations:

• An Active direct system includes a direct circulation system that pumps water through the collectors into a storage tank. A direct circulation system is an efficient system and is cheaper than installing an indirect system. The most significant disadvantage of these systems is that the collector and water in the pipes are outside. As a result, these types of systems are susceptible to freezing. These are best in warmer areas

•  Active indirect systems are suitable for cold climates where they experience freezing conditions wherein the sun’s energy or direct sunlight heats the transfer fluid, such as propylene glycol. This fluid is heated up inside the solar collectors. It then transmits the heat to the water supply via a heat exchanger in a closed-loop system. These systems are becoming more popular as solar becomes more widespread across the country. The disadvantage to these solar hot water systems is that heat is lost via heat transfer through different liquids.

Main Components of Active Indirect Systems

Heat Exchangers – They are made from metals such as stainless steel and copper. These exchanges are generally liquid to liquid, which uses propylene glycol as the transfer fluid and the other liquid as potable cold water with one or two barriers between the fluids.

These barriers are either a single wall or a double wall. A single wall means the heat transfer fluid and potable water are separated by a single layer of heat exchanger material. In contrast, a double wall is separated by a double layer of heat exchanger material with air in between the two layers.

Passive solar water heaters

Passive solar water heaters or passive systems do not need circulating pumps to circulate the hot water around the tank. The passive solar water heater systems use the physics of convection as the water circulation mechanism. Hotter water rises to the top, and colder water descends, circulating water more efficiently.

Passive solar water systems are often less expensive than active solar water systems since they do not need additional equipment to pump the water.

Passive solar heating systems are generally classified into two categories:

•  Integral collector solar water heaters are enormous, do not require pumps for operation, and are essentially batch water heaters that do not require a storage tank. These solar water heating systems only require Solar collectors and piping. In the ICS Solar water heater, the solar collector acts as a storage tank simultaneously. The house plumbing system has an inlet pipe connected to the bottom of the tank. From the top of the collector, the hot water is usually connected to the backup storage heater. This is an open-loop system as the cold water is heated directly.

Thermosyphon systems are the most popular solar heating systems. The Thermosyphon systems include the solar storage tank, panels, pipes, and valves. The passive solar hot water system utilizes metal flat plate collectors to heat small batches of water on your roof. This is based on a simple physics phenomenon when heated water goes up. Coldwater goes down, resulting in liquid circulation. This is the reason why these passive systems have solar storage tanks installed above the solar panels.

These are typically intended to hold 40 gallons of water. 

A tankless heater is a backup energy source standard in passive systems; these solar water heating systems may be gas or electric water heaters. 

One of the main disadvantages of the passive thermosyphon systems is that they are susceptible to hard water because the flat plate solar collectors are constructed of small pipes. As a result, there is a high chance for the pipes to become clogged.

In cold climates, there is a good chance that water inside the solar collectors can freeze up. The recommendation is to use an indirect closed-loop system filled with antifreeze solution, usually propylene glycol.

The cost of a solar hot water heater is determined by the kind of system and the size of the system you choose.

Smaller passive solar water heater systems may be purchased for as little as $3,000, while a more extensive active system can cost as much as $10,000 or more. 

Solar water heater – How to select the Right Kind

Depending on the climate, various types of solar water heating systems perform better than others.

When it comes to direct systems, they operate best in regions where temperatures seldom drop below freezing. If you live in a cold environment, indirect active systems are more resistant to freezing damage than direct systems.

•  Do you want your solar heating system to serve a dual purpose? Invest in a system that circulates indirectly. Suppose your family uses a lot of hot water throughout the day. In that case, you may want to consider investing in an integrated passive system that can heat your pool or spa in between supplying your house with heated water.

•  Family members will not have to be concerned about running out of hot water for morning showers because of the ability to produce numerous tiny batches of warmed water.

•  Have you had more roof space than you do ground space? A thermosyphon solar water heater is designed to be installed on your roof, allowing you to have more room in your living area.

•  Because integral collector storage systems may weigh more than 400 pounds, you must ensure that your roof is capable of supporting the weight of a large water tank.

Furthermore, you must consider the amount of sunshine your home gets, how much hot water you use daily, and your financial situation. Search for ratings from the Solar Rating and Certification Corporation while looking for solar water heater alternatives (SRCC). Ratings from the SRCC make it simple to evaluate various brands and models by relying on third-party professional data.

 Because every house is different, you should get professional advice to choose the most appropriate system for your residence. Consult with an installer in your region to learn more about the equipment that has been recommended for your project.

How much money can you save with a solar water heater?

Solar water heaters need a significant initial expenditure – in some instances, upwards of $5,000 – to be installed.

Nevertheless, following installation, a solar hot water system will gradually begin to pay for itself by reducing the amount of money you spend on energy bills. Solar hot water heaters may often reduce your water heating costs by 50 percent to 80 percent!

Your solar water heater will continue to provide virtually free hot water for the rest of its useful life after you have reached the end of your solar payback period. In addition, since solar water heaters do not have any moving components, they offer minimal maintenance requirements and expenses.

Always keep in mind that, based on how much hot water your household consumes, you may be required to utilize a backup grid-connected hot water system.

You’ll need to know the following information to assess your potential savings:

•   How much hot water your household consumes daily (if applicable).

•   This includes the cost of gasoline for your backup heater. For additional information on the energy expenses associated with backup heaters, contact your local utility provider.

•   The SRRC, also known as the solar energy factor rating, of the equipment you plan to use. These figures will give you an idea of how effectively your appliance will utilize its collected solar energy.

•   When you use hot water, consider how much of your use happens during daytime hours. When less sunlight is available, more hot water is used, increasing the dependence on expensive grid electricity.

•   Your solar water heating system’s expected lifespan is shown below. The longer the life expectancy of your heating system components, the more money you’ll save. You can calculate the yearly running cost of your solar water heater using the information you have gathered. When you compare this to your average monthly utility expenditures, you can see how much energy you might save by converting to solar power.

What rebates and incentives are available for solar water heaters?

The Investment Tax Credit frequently referred to as the federal solar tax credit, provides a tax credit equivalent to 26 percent of the installation expenses of a solar water heater in a residential or commercial building. For example, let us assume that your solar water heater costs $5,000. You’ll get a tax credit of $1,300, which will reduce the total cost of your system to only $3,700, saving you money.

It is also possible that your local utility provider may provide special discounts or rebates for installing qualifying equipment. Customers who install a solar water heater, for example, may qualify for a $750 refund from Hawaiian Electric Company.

Find a solar water heater installation in your region to help you save money on your energy bills while maintaining your comfort.

Which option is ideal for you – whether to receive just one or both of the options.

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