What Is a Solar Water Heater?
A solar water heater is designed to provide hot water to a building as a traditional unit would, except that these heaters use solar energy to heat the water through various methods, depending on the type of solar tank chosen. Solar water heaters are available in numerous designs, but all include collectors and a storage tank. There are two main types of systems to choose from: active and passive.
An active system uses a pump to circulate the water to heat it. A passive system relies on gravity to move the fluid through the system. Active systems use direct or indirect circulation, while passive systems are all indirect circulation based on natural convection and gravity. Because of this, passive systems are far less efficient and are usually only used to preheat water for a conventional system rather than to heat the water for the entire home. Active systems lower energy bills faster because they heat larger amounts of water and eventually replace a conventional system. In contrast, a passive system will be an add-on to your existing heater, so it may only save a small amount on energy bills.
Solar Water Heating System Cost by Type
The cost for a solar system by type ranges from $1,000 to $4,000 for the unit only. There are two types of solar water heaters: active and passive. The most basic of the two systems is the passive system, which relies on gravity to function. Active systems are more complicated and use a furnace or boiler to heat the water and pumps to push the water through the collectors. These additional parts also make active systems more expensive in most cases. Active systems are available in indirect and direct styles. Passive systems also come in two styles: integral collector storage or thermosyphon. In the table below, you will see the costs of each system, not including labor or installation.
| Type | System Cost (Unit Only) |
|---|
| Passive | $1,000 - $3,000 |
| Active | $2,000 - $4,000 |
Passive Solar Water Heater Cost by Type
You can expect to spend $1,000 to $3,000, on average, for passive solar water heater units. Passive systems are more affordable than active systems, but 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. The two types of passive solar water heating systems include the integral collector storage and the thermosyphon. In the table and subsections below, you’ll see the types of passive heaters, their features, costs, and other information.
| Types | Heater Cost (Unit Only) |
|---|
| Integral Collector Storage | $1,000 - $2,000 |
| Thermosyphon | $1,500 - $3,000 |
Integral Collector Storage Passive Systems
An integral collector storage system costs from $1,000 to $2,000. The integral collector storage (ICS), 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. This transparent tank is installed in the yard and the sun heats the water inside of the tank. The necessity of direct heating from the sun limits its capacity but the integral collector storage passive system is highly energy-efficient and inexpensive compared to other systems. However, these systems only function in areas with very mild or warm weather conditions because they can lose their heat very quickly if it is cloudy, cold, or at nighttime.
Thermosyphon Solar Water Heating System
The price ranges from $1,500 to $3,000 for thermosyphon systems. The thermosyphon solar water heating system is available as both a direct and an indirect unit. This system either moves water through the collector (direct) or moves the heat transfer fluid to heat the water (indirect). The units that operate by using the heat transfer fluid work best in areas with freezing temperatures because you can use a drainback system to empty the pipes and collectors to prevent freezing of the system. The main drawback of this system is that the tank must be placed higher than the collector, which leads to the second drawback: the weight of the tank, which is extremely heavy and difficult to install on a home’s roof. This places excessive weight on the structure, as well. 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.
Active Solar Water Heater Cost by Type
An active solar water heater costs between $2,000 and $4,000. Installing 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. 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. In the table and subsections below, you will see both types of active systems and their features, costs, and more.
| Type | Heater Cost (Unit Only) |
|---|
| Direct / Open Loop | $2,000 - $3,000 |
| Indirect / Closed Loop | $3,000 - $4,000 |
Direct Solar Water Heating System
The typical cost of a direct solar water heating system with one collector and a tank averages $2,000 to $3,000. With direct active systems, the water is stored in the holding tank, and then pumped through the solar collectors and back to the storage tank, which distributes the hot water to the rest of the house. People often favor direct active systems in areas with ample sun because it is the most affordable of the two systems. However, the indirect active system is usually used in cloudy or cold regions. Both types of active systems are extremely energy efficient.
Indirect Solar Water Heating System
An active indirect solar water heating system with one collector and tank averages $3,000 to $4,000. The indirect active system uses a heat-transfer fluid like glycol, freon, or even distilled water. This fluid circulates through the solar collectors located on the roof and back into the tank through the system’s heating element, also known as a heat exchanger, to heat the water held within the storage tank. This warms the water, which is then directed to the house from the storage tank.. The system functions in areas with freezing temperatures but is less energy efficient in warmer climates. A drainback system can be a beneficial choice to help keep the system from freezing. This closed-loop system pumps a heat-transfer fluid (HTF) through the collectors and into the storage tank. The difference with this system is that when it is turned off, the HTF drains out of the pipes and collectors so that they are empty and will not freeze, which could cause damage or other issues.
Solar Water Storage Tank Price by Size
The price of the tank ranges from $1,000 to $8,000 when it is priced by capacity. In addition to single and double-walled tanks, solar tanks also offer five standard sizes, ranging from 30 to 120 gallons. The tank is paired with a backup electric or gas heat source, so you do not 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 with a built-in heat exchanger, or a direct tank with built-in auxiliary heat. In the table below, you will see the different sizes and their average costs for the unit only.
| Size | Tank Cost (Unit Only) |
|---|
| 30-gallon | $1,000 - $2,000 |
| 60-gallon | $2,000 - $4,000 |
| 80-gallon | $2,500 - $5,000 |
| 100-gallon | $4,000 - $6,000 |
| 120-gallon | $5,000 - $8,000 |
Solar Water Heater Collector Price by Type
You will spend between $600 and $4,500 on the collector for your solar water heater, depending on which style you choose. 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, much like the basic function of any solar panel or collector system. The larger the collector surface, the quicker it can heat. Typically the collector is installed on the roof to collect as much sunlight as possible. The table and subsections below show each type, its costs, and other information.
| Type | Collector Cost (Unit Only) |
|---|
| Flat Plate Collector | $600 - $1,200 |
| Evacuated-Tube Collector | $1,200 - $4,500 |
Integral Collector-Storage System / Bulk Collector
| $3,000 - $4,000 |
Flat Plate Solar Collector Price
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.
Evacuated Tube Solar Collectors Price
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. Also known as the evacuated vacuum tube collector, 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.
Integral Collector Storage System
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 break down. 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.
Solar Water Heater Prices by Brand
Those pricing solar water heaters by the brand expect to spend between $2,000 and $9,500 for the unit only. Several brands make solar-powered water heaters, and each model will have its own features and costs to consider. If you want to work with a leader in HVAC solutions, a Rheem solar water heater could be ideal. This is one of the brands that offers quite a bit of selection. Brands like Sunbank solar water heater models only focus on passive water heaters. Duda, Apricus, and Sun Earth solar water heater models are known for their strong passive systems. However, all the brands offer different options for different needs. In the table below, you will see each brand and the average cost for the water heater unit only.
| Brand | Heater Cost (Unit Only) |
|---|
| Sunbank | $2,000 - $6,000 |
| Duda Diesel | $2,900 - $6,000 |
| Apricus Solar | $3,000 - $8,000 |
| Sun Earth | $4,000 - $9,000 |
| Rheem | $5,000 - $9,500 |
Solar Water Heater Installation Cost
Of the average $9,000 it costs to install a solar water heater, about $4,000 goes towards labor and installation costs, while the rest makes up the cost of the unit. 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 installation process begins with mounting solar collectors on the roof. Then, the storage tanks and heat exchanger will be installed inside the building, followed by the piping systems and water transport systems. Then, the control unit will be installed, and the entire system will be insulated. Contractors will test the operation of the new solar water heater, and then the work will be complete. You will be left to enjoy your new eco-friendly water heating solution.
What Size Solar Hot Water System Do I Need?
As with any water heater system, it is important to choose the right tank storage size based on the needs of the home. Typically, the standard rule of thumb says you should allow 20 gallons of hot water per day for each person that is in the home. The process of sizing a collector is a little bit more complicated, but your installer should be able to help with this. For one to two people, a 40 sq.ft. collector could be sufficient. You will need to add 8 to 14 sq.ft. for each additional household member. So, for five or more people, you would need about 82 sq.ft. of coverage. In the table below, you will see the storage tank capacity for different household sizes.
| Family Size | Capacity in Gallons |
|---|
| 1 - 2 People | 30 - 60 |
| 3 - 4 People | 60 - 80 |
| 4 - 5 People | 80 - 120 |
Maintenance
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.
Pros and Cons
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 vs Gas Water Heater Price
Solar water heaters are easy to install and last up to 20 years. A gas water heater is easy to install, but gas can be quite expensive--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 strength of the sun 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. In the table below, you will see the average cost for each type of water heater, with costs for an 80 gallon tank installed.
| Type | 80-Gallon Heater Cost (Installed) |
|---|
| Gas | $2,150 - $5,000 |
| Solar | $4,500 - $9,000 |
Solar vs Electric Water Heater Price
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. In the table below, you’ll see the average installation costs for an 80-gallon tank.
| Type | 80-Gallon Heater Cost (Installed) |
|---|
| Electric | $2,900 - $4,000 |
| Solar | $4,500 - $9,000 |
Enhancement and Improvement Costs
Cost to Install Solar Pool Heater
A solar pool heater costs $3,000 to $7,000 to install, depending on the features and other factors. If you want to enjoy warm water in your swimming pool year-round, you might want to install a solar pool heater. A heater means you can swim no matter the outside temperature, which is a great enhancement. If you require a high-temperature collector that is mounted on your home to heat a larger pool measuring 10 feet x 36 feet, you might pay about $10,000.
Radiant Heat System Cost
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.
Solar Water Heater Backup System
The national average to install a water heater backup system is $200 to $300. 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.
Additional Considerations and Costs
- Energy savings. The solar water heating system can heat up to 40 percent of the average home’s water needs. The use of the system reduces your home’s yearly water heating energy cost by 50 percent, according to Energy Star. Your savings depend on your location.
- Rebates and tax credits. Solar water heating systems are frequently eligible for incentives, rebates, and tax credits. Please check with your local energy provider and state/federal tax system to determine eligibility requirements.
- Qualifying circumstances. To qualify for a federal tax credit, at least half your home’s energy to heat water must be gathered from the solar water heater. You do not have to have a whole-house system to qualify. Under the federal tax credit, you can only claim the money you spent on the solar water heater and no other hot water sources within your home. You cannot claim the credit if you use the solar water heating system to heat a pool or spa.
- Compliance. OG-300 Solar Water Heating System Certification Program gives you proof of compliance that your solar water heating system meets all standards set forth by building codes and incentive programs for North America. They are also used for U.S. Federal tax credits, the EPA ENERGY STAR program, and the California Energy Code.
- Location. Before investing in a solar water heating system, you should always make sure that your site works for the collectors. Will the collectors receive adequate sunlight from 10 a.m. to 4 p.m. year-round? Will your home’s roof hold the collectors, or will you need a location by your home to place the collectors where they will receive sunlight? You also must determine what type of system meets your needs. If you live in a cold region, avoid systems prone to freezing.
- Permits and codes. You must investigate your local building codes, HOA regulations, and zoning ordinances before installing a solar water heating system. Not all regions welcome such renewable energy options. Many have very strict rules that govern where the collectors can be placed, the load capacity, and other considerations.
- DIY. Installing a solar water heater system is very complicated and should only be undertaken by a qualified professional. Many things must be considered when installing a solar water heating system, such as the regional climate, specific building codes, safety, and the availability of solar at the location. Ideally, you should have a qualified solar thermal systems contractor safely and efficiently install your system.
FAQs
- How much does it cost to install a solar water heater?
A typical four-person household requires only a 100-gallon solar water heater and collectors, which averages $8,000 to $10,000.
- How long does it take for a water heater to heat up after installation?
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.
- How much does solar energy cost per year?
The price of solar energy has fallen to less than 3 per kilowatt per year.
- How does a solar water heater work?
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.
- How long does a solar water heater last?
Most solar water heaters last up to 20 years.
- Do solar hot water panels need cleaning?
Yes, bird droppings and other debris accumulate on the surface of the solar collectors, so they do require frequent cleaning.
- Do solar panels work without direct sunlight?
They do not require direct sunlight to function. The panels depend on photons from the sun to function, which they obtain without direct light.
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