Solar water heaters are also referred to as solar domestic hot water systems. The device is a cost-efficient way to heat water using the thermal power of sunlight. A solar water heater has a water storage tank and solar collectors which effectively warm the water.
The national average cost for installing a solar water heater is between $8,000 and $10,000, with most people paying around $9,000 for a fully-installed, 100-gallon solar active indirect hot water heating system. At the low end of the spectrum, however, you can opt for a smaller tank that holds only 60 gallons and costs about $4,000 when fully installed. At the high end, you pay up to $13,000 to have a 120-gallon tank with a dual heat exchanger fully installed with a collector.
|Solar Water Heater Cost|
|National average cost||$9,000|
|Average range||$8,000 - $10,000|
There are two types of solar water heaters: active (indirect and direct) and passive (integral collector-storage or thermosyphon). The most basic of the two systems is the passive, which relies on gravity to function. Active systems are more complicated and use a furnace or boiler to heat the water. Pumps push the water through the collectors, so they tend to be the more expensive option.
Below is a table outlining the cost differences between active (indirect and direct) and passive (integral collector-storage or thermosyphon) systems. The costs outlined in the table include materials only and do not include labor or other factors needed to complete the entire installation process:
|Type||Cost per Unit|
|Passive (integral collector storage or thermosyphon)||$1,000-$3,000|
|Active (indirect and direct)||$2,000-$4,000|
Passive systems are more affordable than active systems, but they are less energy efficient. One of the main drawbacks of the passive system is that it quickly runs out of hot water on a cloudy day. With a passive system, most homeowners must keep their existing system to keep hot water when the sun is not shining. A passive system can only heat about 40 percent of the home’s water. Another drawback to this system is the weight of the unit, which is extremely heavy and difficult to install on a home’s roof. This places excessive weight on the structure.
The two types of passive solar water heating systems include the integral collector storage and the thermosyphon. The integral collector storage (ICS), which is also called the “batch” system, is the most affordable of the two and tends to be the most favored by homeowners due to its ease of installation and basic requirements. In the United States, the thermosyphon system is very rare. It is far more common in Japan, Israel, and Australia, where it has been the favored system for the last 30 years. The average cost of these two systems runs from $1,000 to $3,000
An active solar water heater relies on solar collectors and a heat storage area to function. The storage area holds water and is equipped with a built-in internal electric or gas backup. With the storage area, you can have water even if several days are cloudy. With such a system, you do not need a backup unit. The main drawback of this system is that it is more expensive. Both direct and indirect active solar water heating systems average $2,000 to $4,000, with the indirect system being the costliest.
Active systems are available in two versions--direct and indirect. With direct active systems, the water is heated from the sun, but the indirect fluid is used to warm the water. People often favor direct active systems in areas with ample sun because it is the most affordable of the two systems. However, in cloudy or cold regions, the indirect active system is usually used. Both types of active systems are extremely energy efficient.
The installation of an active solar water heater involves mounting the solar collector directly on the roof. Often, a portion of the roof must be removed during installation. A storage tank and heat exchanger are then installed in the home (usually in the basement or a utility closet). Piping systems for the transfer of fluid are run, and water pipes are installed. All control systems for the unit are installed last and connected to operate. Active systems are commonly used in areas with cold/freezing temperatures. Many homeowners choose active systems because the tank can be conveniently hidden inside a closet or basement. With other systems, the tank must be located higher than the collectors, such as on the roof.
|Types of active solar water heaters||Cost per unit (only materials)|
|Direct, 1 collector and tank||$2,000-$3,000|
|Indirect, 1 collector and tank||$3,000-$4,000|
The direct system pushes the water through the collectors to heat for the storage tank. It is an energy-efficient system that is favored for warmer climates. Unfortunately, the system does not work well in areas with freezing temperatures. You can only install the system in regions that have mild winters. The typical cost of a direct solar water heating system with one collector and a tank averages $2,000 to $3,000.
The indirect active system uses the main furnace or a boiler to warm the heat transfer fluid effectively. This fluid circulates through the system’s heat exchanger to heat the water held within the storage tank. The direct active system then pushes the water through the collectors to heat for the storage tank. One perk of the system is that it turns on and off less often than the direct solar water heating system. The system functions in areas with freezing temperatures but is less energy efficient in warmer climates. It relies on a high-efficiency boiler or heating system to warm the heat transfer fluid. An active indirect solar water heating system with one collector and tank averages $3,000 to $4,000.
A passive integral collector-storage requires no pumps and is entirely passive. They are a single unit that consists of a tank with a collector. The tank is installed directly on the roof and then transfers to the collector. No pump moves the water, but instead, the entire system relies on gravity to create water flow. Piping is installed to flow from the collector to the storage tank. Finally, the basic control system is installed to control the unit. With units such as the thermosyphon solar water heating system, the tank must be higher than the collector. They are ideal in areas that suffer from power outages because they rely on gravity and the power of the sun. This system can still heat water without electricity. They are ideal for people who live off the grid.
|Types of passive solar water heater||Cost|
|Integral collector storage passive systems||$1,000-$3,000|
|Thermosyphon solar water heating system||$1,000-$3,000|
The integral collector storage passive system is highly energy-efficient and inexpensive compared to other systems. However, it only functions in areas with very mild or warm weather conditions. A major drawback is that it heats only about 40 percent of the household’s hot water, so you will be left having to keep your conventional system as a backup. The cost ranges from $1,000 to $3,000.
The thermosyphon solar water heating system is available as both a direct and an indirect unit. This system either moves water through the collector or moves the heat transfer fluid to heat the water. The units that operate by using the heat transfer fluid work best in areas with freezing temperatures. The main drawback of this system is that the tank must be placed higher than the collector. This type of system only heats about 40 percent of the water for the household. You will need to keep your existing hot water system as a backup. The price ranges from $1,000 to $3,000.
You can choose from single- or double-walled tanks. The tanks range in size from 60 gallons to 120 gallons. The tank is paired with a backup electric or gas heat source, so you don’t have to worry about taking a cold shower during the night or when no sunlight is readily available to heat the water. You can choose from simple storage-only tanks, indirect backup tanks that come with a built-in heat exchanger, or a direct tank with built-in auxiliary heat. The price of the tank ranges from $2,000 to $5,000.
|Tank size||Price per unit (only materials)|
|100-gallon tank with built-in heat exchanger||$4,000|
|120-gallon tank with built-in auxiliary heat||$5,000|
A solar water heater collector captures and retains the sun’s UV rays to heat the water or liquid in the water heater. The collector is the large panel seen on the rooftop that most people associate with solar power. It works by creating thermal equilibrium and balancing heat loss with convection, radiation, and conduction. The larger the collector surface, the quicker it can heat. Typically the collector is installed on the roof.
|Collector type||Cost per unit (only material)|
|Flat Plate Collector||$600-$1,200|
|Evacuated-tube solar collector||$1,200-$4,500|
|Integral collector-storage system/Bulk collector||$3,000-$4,000|
The flat plate solar collector is a thrifty option. It typically averages about $600 to $1,200. The collector plate effectively absorbs the diffuse solar energy that has been reflected off the surface. It is permanently affixed to the roof, so you don't’ have to worry about it blowing off. It requires no tracking system and is easy to maintain. One drawback is that air pockets can collect in the collector’s tubes. Also, the transport of water or heat diffuser liquids can become blocked due to air pockets or other debris.
The evacuated tube solar collector price runs about $1,200 to $4,500. The main benefit of this system is that it produces more heat than others. It is also less prone to freezing than the flat panel collector models. It quickly absorbs solar energy and does not suffer radiative heat loss. One of the drawbacks is that it might not make enough hot water for the home during the winter months. Also, the internal tubes can break. Unlike classic collectors that resemble flat panels, the evacuated tube solar collectors look like many elongated tubes hooked together. The tubes contain a fluid used to heat the water in the tank. This form of the collector overheats easily.
The price of the integral collector storage system averages $3,000 to $4,000. It is simple to work on and maintain, a definite perk to the system’s design. The collector requires no complicated pumps to operate. It needs no electronic controls or heat sensors. Simplicity means that there are fewer things to malfunction or breakdown. Unfortunately, the system suffers nighttime heat loss. It might be appropriate in regions of the country that experience freezing weather. The integral collector system is very similar in appearance to the flat plate panel collector, but it boasts very large heat tubes encased in a box. With this system, the collector and tank are combined.
A solar water heater involves numerous parts, depending on what type you purchase. In general, the system includes a collector, which is the flat apparatus that gathers the sun’s thermal energy. These are typically placed on the home’s roof in a south-facing location. A built-in pump in an active system moves the water or heat transfer solution through the tubes to the collector and back to the tank. The heat exchangers are built-in and transfer the sun’s thermal energy, absorbed in the collectors, to the liquid or air used to heat the water.
Depending on the solar heating system that you purchase, you will be provided with controllers that offer a range of features such as sensor 3 inputs, remote monitoring, and relay controls. The price of parts varies depending on the brand, size, type, and even where you live. It pays to shop around to find the most affordable prices. Many times, only a simple part in a solar water heater goes out. You can easily replace it without installing an entirely new system. Below is a table that outlines the cost of some of the most common parts.
|Part||Cost per part (materials only)|
|Controller system (Flow control valve)||$25|
Simple valves control the water in a solar water heater. As time goes by, the valves can fail or malfunction and require changing. You can usually choose between a double- or single-walled tank. The double-walled offers more insulation. Double-walled are for regions that have hard freezes. All systems come with the plumbing that connects the collector to the tank. The plumbing also comes equipped with shutoff switches that can be used during repair or maintenance. The price of a valve is affordable, averaging around $25. However, you will probably need a plumber to install the valve. Expect to pay $45 to $200 per hour for a plumber’s services. Replacing a valve usually takes two hours.
If your home does not have a current water heating system, you’ll need to install a solar water heater backup system. The system is either a gas or electric water heater, which you rely on to heat your water if the weather conditions are cloudy, and you cannot use solar to heat the water. The national average to install a water heater backup system is $200 to $300.
Before embarking on the installation process, your installer should conduct a solar site analysis to determine the expected efficiency. At that time, they will determine the correct orientation and tilt of the solar collectors to ensure that they heat the water optimally in your solar hot water tank. Also, the installer will determine how many solar collectors you need to purchase to utilize the sun’s existing rays adequately. These services are typically included in the cost of installation.
You will want to choose a company that specializes in installing solar hot water systems. Usually, the place where you purchase the unit has contractors available to install the system. You may need to hire a general plumber to run the necessary plumbing. Most companies charge from $2,000 to $4,000 for the system installation and positioning of the collectors. Solar contractors usually charge an average of $70 per hour. If you decide to have a plumber run pipes for the storage tank, you will spend $45 to $200 per hour for a plumber’s services.
The cost of a 100-gallon solar system with a single collector and tank averages $5,000 depending on the brand. Labor, plumbing services, and the solar contractor fees average $4,000. You will spend about $9,000 when fully installed. However, you can opt to go cheaper by installing a 60-gallon tank that averages only $2,000 and takes about $2,000 in labor, plumbing, and solar contractor services for a total of $4,000 when fully installed. If you want a top-of-the-line solar water heating system, then you can choose a 120-gallon tank with a dual heat exchanger for a price of about $5,000, and labor, plumbing, and solar contracting services will run around $8,000. The price to have the premium unit installed averages $13,000.
Solar water heaters are available in numerous designs, but all include collectors and a storage tank. An active system uses either direct or indirect circulation. With a direct system, a pump circulates the water through the collectors to heat the water. With an indirect system, the water does not circulate through the collectors. The indirect system uses a non-freezing heat-transfer fluid instead of water. The heat transfer fluid flows through the collectors to absorb the sun’s solar warmth and then travels into the storage tank to heat the water.
A passive system is far less efficient and often only used to preheat water for a conventional hot water system. In such a system, natural convection circulates the water, so the tank must be placed higher than the collection panels. The water must flow upward to the tank, and the cold water flows down for heating. This system only functions in areas that never deal with freezing weather.
Once installed, the solar water heating system requires regular inspections to ensure that the collectors are functioning properly, have no cracks or loose bolts, and remove any accumulated debris. The homeowner can perform a visual inspection and perform some general maintenance. However, having a solar maintenance person perform maintenance every three years is recommended. The technician charges around $70 per hour. An acidic solution must be circulated through the collectors and pipes every three to five years to prevent corrosion and debris buildup that clogs the pipes. In systems that require antifreeze fueling liquids, the liquids must be checked every three to five years.
With a solar water heater, you can harness the sun’s free thermal energy to save money and reduce your carbon footprint. Your home’s energy consumption will be significantly reduced. Also, they are easy to maintain and operate quietly. You do not require large units to operate the water heater. You only need two or three standard-sized solar panels to operate the water heater; you don’t have to worry about your roof being covered in unsightly panels. Installing a standard water heater does not increase the value of your home, but the addition of a solar water heater can increase your home’s value by up to 27 percent according to the U.S. Department of Energy.
In many areas, solar water heaters are eligible for heat or energy incentives, which help you save additional money. The only drawback is that the tank takes up more space than your standard water heater. Also, you’ll need a backup powered tank to make sure your home always has sufficient hot water. You are at the mercy of the sun to determine if you will have hot water. In areas with frequent cloud cover, your solar water heater might not heat enough water for your home. In regions with very hot weather, the water in the tank can quickly reach scalding temperatures during the summer months.
Solar water heaters are easy to install and last up to 20 years. A gas water heater is easy to install, but gas is not available in all areas--unlike solar, which relies on the sun’s rays to function. Also, a solar water heater costs more to install than a gas model. A solar water heater does not always provide instant hot water, unlike a gas water heater, which has a quick recovery time. With a gas water heater, you never have to worry about having warm water. It functions year-round with no problems, but a solar water heater depends on the sun’s rays to warm the water. If it’s cloudy, the water might not heat up. Typically, with a solar water heater, you have to have a backup water heater option to ensure you always have year-round warm water and a gas model requires no backup.
|Gas water heater (50 gallons)||$600-$1,500|
|Solar water heater (100 gallons)||$8,000-$9,000|
A solar water heater relies on the sun to warm the water, making it energy-efficient and eco-friendly. An electric water heater uses electricity to warm the water. However, with an electric water heater, you have a non-stop supply of warm water year-round. A solar water heater depends on the sun’s rays, so it might not have a ready supply of hot water on cloudy days. A solar water heater lasts about 20 years. An electric unit typically makes it about a decade. With an electric water heater, you can control the temperature easily. Another perk of an electric water heater is that you do not have to have collectors on the roof (which many people consider unsightly). If cost is a determining factor, then an electric water heater is far cheaper to purchase and install.
|Electric water heater (50 gallons)||$600-$1,500|
|Solar Water Heater (100 gallons)||$8,000 - $9,000|
If you want to enjoy warm water in your swimming pool year-round, you might want to install a solar pool heater. A solar pool heater averages from $3,000 to $7,000 to install. Most homeowners spend around $5,000 to install a glazed solar-panel pool heater, which heats the water in a 12-foot x 24-foot in-ground pool. However, if you opt to install unglazed solar panels to heat a 10-foot x 20-foot inground pool, then you can expect to pay about $2,000. If you require a high-temperature collector that is mounted on your home and will heat a large pool measuring 10 feet x 36 feet, you might pay about $10,000.
A tankless water heater is favored for residential use. It heats the water quickly and does not store it in a tank. The average cost to install a tankless water heater in your home is around $2,500 to $4,500. If you opt to purchase a gas tankless whole house unit, you will pay about $2,800. With a tankless water heater, you don’t have to worry about having a large water storage tank in your home, so they save space.
A solar water heater can be used in conjunction with a hydronic radiant heat system to complement each other and obtain even greater energy savings. Hydronic heating needs a water heater to heat water that is circulated under the flooring through flexible tubes. They are the type most commonly installed. Their average price is $14,000 to $48,000 for a 2,000 square foot home. Typically, most homeowners spend around $28,000.
A typical four-person household requires only a 100-gallon solar water heater and collectors, which averages $8,000 to $10,000.
If the solar heater is hooked to an electric water heater, it takes about an hour to an hour and 20 minutes for the water to heat. If the water heater is not hooked up to a backup energy source, you could wait several days for an entire sunny day for the water to heat up. If the conditions are cloudy, it could take days to heat.
The price of solar energy has fallen to less than 3 per kilowatt per year, according to Energy Sage.
The sun produces thermal energy, which effectively heats the fluid within the collectors. The fluid then goes on to heat exchangers located in the storage tank, which work to heat the water. With a direct system, the water is circulated through the solar collectors so that the sun can directly warm the water.
Most solar water heaters last up to 20 years.
Yes, bird droppings and other debris accumulate on the surface of the solar collectors, so they do require frequent cleaning.
They do not require direct sunlight to function. The panels depend on photons from the sun to function, which they obtain without direct light.