Solar Water Heater: Solar Water Geyser: Solar Water Warmer: Solar Water Heater Price

A solar water heater is a solar thermal device that uses the sunlight to heat water for domestic and commercial applications. It goes by many different names, including a solar hot water system, solar water warmer, solar geyser, and a domestic hot water system. While there are several types of these systems, the core components typically include solar collectors, an insulated water storage tank, connecting pipes, and a supporting stand.

Solar hot water systems can be categorized based on the following:

The collector technology: These types of solar water warmers include flat-plate collector solar water heaters, evacuated tube solar-powered water heaters, and batch collector solar hot water heaters.
The circulation mechanism: These include active solar water heaters and passive solar water heaters.

In this blog, you will learn how solar water heaters work, their different types, benefits, and limitations, and whether solar water heaters are better than rooftop solar panel systems for homes and housing societies in India.

TL;DR Summary Box: Is Solar Water Heating Worth It?

Installing a solar water heater can cut down electricity bills and reduce pollution. Installing them is absolutely worth it. However, if you want to see a reduction in your bills by at least 90%, replacing just one appliance like a geyser with its solar alternative won’t help. In such cases, you’ll need an on-grid rooftop solar system that can generate electricity to run all your household appliances.

Here are the key pointers we’ve covered in detail in this blog:

Topic	Quick Takeaways
What is a solar water heater?	A solar water heater uses sunlight to heat water through thermal collectors. It provides hot water for homes and businesses without relying on electricity.
What are the main types of solar water heaters?	Based on technology: flat-plate, evacuated tube, and batch collectors Based on circulation: active and passive
How to choose a solar water heater for home?	Consider your climate, hot water usage, roof space, budget, and tank placement needs to pick between active and passive solar water heaters.
Which is better, solar PV systems or solar water heaters?	PV solar systems power the entire home and cut electricity bills drastically by at least 90%. Solar water heaters are limited to heating water
Benefits of solar water heaters	Saves energy, lowers bills, eco-friendly, low maintenance, and can last 25+ years with proper care.
Limitations of solar water heaters	Weather-dependent, needs a lot of rooftop space, higher upfront cost, and doesn’t generate electricity from sunlight like solar panels do.
How to maintain solar water heaters?	Clean the collectors, check for leaks, inspect insulation, and service pumps or fluids periodically.
How long do solar water heaters last?	15-20 years

What is a Solar Water Heater and How Does it Work?

A solar water heater uses sunlight to produce thermal energy, which can be used to heat water. The thermal solar collectors in these solar renewable energy systems collect heat from sunlight and use the circulating pipes to transfer that heat to the water present in the storage tank.

The best advantage of solar water geysers is that, since they do not require electricity to work, they reduce electricity bills.

Core Components of a Solar Water Heater

Solar water heaters use heat from sunlight to work. The heat captured is used to raise the temperature of the water stored in the insulated water tank. The basic working principle of solar geysers revolves around the following core components:

Solar collectors: They absorb sunlight and convert it into heat, which is then used to raise the temperature of the water.
Storage tank: This is an insulated container which helps maintain water temperature for long periods without losing heat to the surroundings.
Circulation system: This is responsible for moving water between collectors and the storage tank.
Control system: It’s used to manage the flow of water and temperature regulation.
Backup heating element: This helps provide hot water during cloudy days or high-demand periods.

Step-by-Step Working of Solar Water Heaters

Let’s learn the step-by-step working principle that these systems use to provide solar-powered hot water to homes and industries:

Step 1 – Solar collectors absorb sunlight: Flat-plate collectors (FPC) or evacuated tube collectors (ETC) are most commonly used as solar collectors. Their job is to absorb sunlight. In order to maximize sunlight absorption and minimize heat loss, the surface of solar collectors is coated with a selective coating. Finally, thermal energy gets captured as collectors heat up due to sunlight.
Step 2 – The heat collected is transferred to a circulating fluid: Water or heat-transfer fluid that is present inside the collector tubes absorbs the heat captured by the collectors. As this fluid heats up, it becomes less dense than air and begins moving upward due to natural convection in passive solar water heaters or is pumped in active solar water heaters.
Step 3 – The heated fluid is circulated to the insulated storage tank: In passive solar-powered water heaters, the heated water rises naturally and enters the insulated storage tank that’s placed directly above the collectors. In active solar hot water heaters, pumps controlled by sensors circulate the hot fluid to the storage tank.
Step 4 – Hot water is drawn from a tap outlet when needed: The storage tank, made of stainless steel or glass-lined material, is fitted with PUF (polyurethane foam) insulation, enabling it to retain heat for extended periods. The hot water naturally stays at the top, and cooler water sinks to the bottom.
Step 5 – Optional back-up heating for cloudy days: This is an optional hybrid setup that ensures reliability and user comfort year-round. An electric heating element or gas booster in the tank activates during cloudy days or high usage periods to provide an uninterrupted hot water supply when sunlight is scarce or demand is so high that solar heating alone isn’t enough.

What Are the Types of Solar Hot Water Heaters?

Solar water heaters are categorized based by either the solar collector technology used or the circulation mechanism of the heater. The three main types based on collector technology are flat-plate collector solar water heaters, evacuated tube solar-powered water heaters, and batch collector solar hot water heaters.

The two types based on the circulation system are active solar water heaters and passive solar-powered water heaters.

Types of Solar Water Heaters Based on Collector Technology

These types of solar water heaters are classified on the type of collector technology they use. Let’s check out the three main types in detail:

Flat plate collector solar water heaters (FPC): These resemble a glass-covered box that contains black-colored metal plates that work as absorbers. Their job is to absorb sunlight and heat up. The outer cover of these systems is insulated to prevent the heat collected from escaping into the surroundings.
Evacuated tube solar water heaters (ETC): The tubes in these systems work like a thermos. There’s a smaller tube placed inside a larger tube, and between them, there’s a vacuum. This vacuum is the reason why these solar water heaters are so efficient. The vacuum doesn’t allow the heat to escape. They’re ideal for cold weather conditions, but can be twice as expensive as the flat plate collector solar water heaters.
Batch collector solar water heaters (ICS): They store heat and water in the same unit. Sunlight hits the box, warms the tank, and heats the water directly. Since it holds both the collector and the storage together, it’s called an Integrated Collector-Storage (ICS) system. If the water stays inside too long on a sunny day, it can get extremely hot. To prevent burns, a tempering valve is added. This mixes in some cold water before it reaches taps. They are not recommended in areas with freezing temperatures.

For added clarity, here’s a tabulated snapshot citing differences between the three types of solar water heaters based on technology:

Feature	FCP Solar Water Geyser	ETC Solar Water Geyser	ICS Solar Water Geyser
Working principle	Sun heats a flat absorber plate Heat is transferred to fluid in copper tubes	Sun heats fluid in an inner tube Vacuum layer traps heat	Sun heats water directly in a tank or tube within an insulated box
Structure	Flat absorber plate with tubes in an insulated box	Multiple glass tubes with vacuum insulation and inner fluid pipe	Tank and collector in one box
Heat loss	Moderate	Very low heat loss due to vacuum layer	Higher heat loss, especially at night or in cold weather
Efficiency	Moderate efficiency Reliable in sunny climates	Highest efficiency Performs even in cold and cloudy weather	Lowest among the three Depends on direct sunlight and usage
Cold climate suitability	Performs poorly in freezing temperatures unless protected	Highly suitable	Not suitable High risk of freezing and heat loss
Circulation compatibility	Suitable for both open- and closed-loop systems	Supports both More commonly used with closed-loop systems	Open-loop only Not compatible with closed-loop systems
Installation and space requirement	Flat and compact Mounts easily on rooftops	Requires slightly more space and careful alignment	Bulky Tank must be placed with collector
Initial cost	Moderate	Highest cost per square foot	Lowest cost option
Best for	General household use in sunny regions	All-weather use, especially cold or cloudy climates	Small homes in warm climates

Types of Solar-Powered Water Heaters Based on Circulation Mechanism

These are of two main types: active solar water heaters that use electric pumps to ensure continuous circulation of water, and passive solar water heaters that rely on the thermosiphon effect for water circulation.

Let’s learn about both these types in detail.

Active solar-powered hot water system: Active solar water heaters use electric pumps and smart controllers to ensure water consistently moves between the solar collectors and the storage tank. They work efficiently even when the tank is positioned below the collectors. The primary advantage of these systems is their ability to heat water more quickly due to faster heat transfer. Hence, they’re ideal for large homes and commercial buildings where hot water demand is very high.
Passive solar-powered hot water system: Passive solar water heaters do not rely on electricity. Instead, they use the thermosiphon effect to circulate water as it heats up. The thermosiphon effect is a natural way in which hot water rises automatically and cold water sinks to the bottom. These systems are simple and low-maintenance, but for them to be effective, the storage tank has to be placed directly above the collectors so gravity can automatically control the water flow. Since their efficiency is lower compared to active systems, they are a smart choice for small households.

For added clarity, here’s a tabulated snapshot of the differences between the two types of solar water heaters based on circulation mechanism:

Feature	Active Solar Water Heater	Passive Solar Water Heater
Working principle	Uses electric pumps and controllers to circulate water	Uses thermosiphon effect that’s natural convection to move water
Circulation method	Forced circulation via electric pump	Natural circulation without any mechanical assistance
Power source	Minimal electricity needed to operate the electric pumps	No electricity required whatsoever
Efficiency	Higher efficiency due to controlled flow and better heat transfer	Lower efficiency as it depends on sunlight and gravity
Design complexity	More complex as it includes pumps, sensors, and control systems	Simpler design since there are no moving parts
Installation flexibility	Flexible tank and collector positioning Tank can be placed below collector	Tank must be above collector for thermosiphon to work
Maintenance requirement	Requires periodic maintenance due to the involvement of pumps, valves, and sensors	Low maintenance due to fewer components and simpler design
Initial investment cost	Higher upfront cost due to added equipment	Lower upfront cost
Operating cost	Slight electricity cost to power the pump operation	Zero operating cost
Ideal for	Large households, hotels, hostels, and commercial use	Small families, individual homes with modest hot water needs
Climate suitability	Works well in any climate, including colder regions with proper insulation	Suitable for mild and warm climates Not suitable for freezing areas

How to Choose a Solar Water Heater For Home?

You need to consider the size of your family, the weather conditions in your area, your budget, and space on your rooftop in order to decide which type of solar geyser is better suited for your requirements.

Let’s take a look at all the factors you need to consider when choosing a solar water heater for home:

Do you live in cold and freezing weather conditions? Select direct active solar water heaters that perform even when temperatures drop below zero.
Does your family use hot water during the daytime, and do you live in a sunny area? You need to invest in a passive solar water heater.
Is there ample space on your rooftop? A passive solar water heater will meet your needs with minimal investment cost.
Is the storage tank placement flexible in your home? Only active systems allow the tank to be placed below or away from the collector. Passive systems require the tank to be above the collectors.
Do you have a limited budget? Passive systems have no moving parts, so they’re cheaper and require less upkeep. But they may not be ideal for cold weather or high hot water demand.
Does your home require hot water during early mornings or late nights? In this case, a system with a well-insulated storage tank and electric backup heater is essential. An active solar water heater will cut the deal.

Solar Hot Water System vs Solar PV Systems, Which is Better and Why?

A solar water heater uses sunlight to heat water through thermal collectors. In contrast, photovoltaic solar systems convert sunlight into electricity, which can power all home appliances, including water heaters. If you want to see a dramatic reduction in your electricity bills (by at least 90%) and become truly energy independent, on-grid solar systems will be a better investment than having a solar water heater.

Installing rooftop solar for housing societies and homes offers multiple benefits that having just a solar water heater can’t provide. Let’s check out all those benefits:

Entire household’s power requirements can be met by solar electricity: You’re not powering just one appliance using solar electricity, but the entire household. A 1 kW solar system in India can produce 1,400 to 1,450 units of electricity annually.
Serious reduction in electricity bills: Since the entire household runs on solar electricity, the bills are reduced by at least 90%. In many cases, SolarSquare’s customers have reported zero bills after installing rooftop solar for homes.
Subsidy offered under the PM Surya Ghar Muft Bijli Yojana: Homeowners installing on-grid rooftop solar get a subsidy up to Rs. 78,000 for solar systems equal to or above 3 KW. However, if you’re installing off-grid solar systems or commercial rooftop systems, you can’t avail of this subsidy as it’s strictly reserved for residential installations.
Quick breakeven and savings in lakhs: Once you get a subsidy, the cost of installing on-grid PV systems breaks even in 3-5 years. Since a well-maintained system lasts for at least 25 years and the electricity tariffs in India rise by 3-6% annually, you’ll save tens of lakhs of rupees over the system’s lifespan. But exactly how much money are we talking about? Let’s understand that in the next section.

How Much Money Can You Save By Installing SolarSquare’s Solar Systems?

We’ve compared the upfront solar panel price (the installation cost) with the savings you’ll make from solar in 25 years in Nagpur. If you’re not from Nagpur but want to calculate your 25-year solar savings, use SolarSquare’s free rooftop solar calculator.

Here’s an estimate of investment vs returns over 25 years.

Solar System Size	Solar Panel Price in Nagpur With Subsidy (Starting Price – Indicative for Base Variant)*	Solar Savings in Nagpur in 25 Years
2 kWp	~ Rs. 1.15 lakh	~ Rs. 11.05 lakh
3 kWp	~ Rs. 1.32 lakh	~ Rs. 16.58 lakh
4 kWp	~ Rs. 1.77 lakh	~ Rs. 22.11 lakh
5 kWp	~ Rs. 2.27 lakh	~ Rs. 34.43 lakh
10 kWp	~ Rs. 5.02 lakh	~ Rs. 68.86 lakh

*Please note: The above-mentioned solar panel price is indicative as of 1st August 2025 for the SolarSquare Blue 6ft variant. The final cost of installing a solar panel depends on your DISCOM charges, product variant opted for, panel type, inverter type, mounting structure height, type of after-sales service, savings guarantee, roof height, etc. Prices are subject to change. Additionally, while calculating savings, we have considered the annual tariff escalation at 3% and the annual degradation at 1%. The actual final savings from solar panel installation depend on the types of solar panels you’ve installed and their efficiency, intensity of sunlight your rooftop receives, orientation of the panels and tilt angle, the pollution level and weather conditions in your city, the temperature, shadow on the roof, impact of dirt/dust, and how well you maintain your panels after installation.

No other investment, not solar water heaters and not off-grid solar systems, can offer the kinds of returns that installing on-grid rooftop solar systems offer.

How to Maintain a Solar-Powered Water Heater?

Solar water heaters have a lifespan of 15-20 years. When maintained well, their lifespan can extend to 25 years or more, giving better returns on your investment. Periodic clearing of the collector’s surface to remove dirt and debris is the first step towards maintaining these systems. This ensures that direct sunlight doesn’t get disrupted and the collector absorbs most of it.

Here are the proper maintenance tips that help prolong the life of solar water geysers:

Surface cleaning: Remove dust, leaves, and bird droppings from collectors.
Connection check: Inspect all pipe connections for leaks or signs of corrosion.
Insulation inspection: Check insulation around pipes and tanks to ensure heat isn’t getting lost.
Pump testing: Check circulation pump operation and pressure levels in active solar water heaters.
Fluid and seal replacement: Replace antifreeze fluid and worn-out gaskets and seals in cold climate systems every 5 years.

Here are some warning signs that you must not ignore:

Temperature drop: Sudden and significant reduction in water heating capability
Unusual sounds: Strange noises from the pump or the circulation system
Visible leaks: Water leakage around tank or pipe connections
Reduced availability: Less hot water, even during normal weather conditions

What Are the Applications of Solar Water Heaters?

Solar water heaters find many uses in residential and commercial applications, such as hot water supply for bathing and washing dishes at homes, bulk solar-powered hot water supply at guest houses and spas, and cleaning operations in textile industries.

Here’s a detailed list of applications of solar-powered water heaters in India:

Hot water supply at homes for domestic use: These systems can provide hot water for bathing, washing, and cleaning. Using them can reduce electricity or gas bills since hot water comes from harnessing sunlight, not electricity. They’re ideal for both single-family homes and multi-story buildings with rooftop access.
For apartments and housing societies: These systems are suitable for centralized solar hot water systems in residential complexes. A single large system can serve multiple households by distributing hot water via insulated piping.
Hot water supply at hotels and resorts: They can be installed at hotels to provide hot water in guest rooms, kitchens, laundry, and spas. The benefit is that they reduce dependency on electric or gas boilers and help the hotels reduce their carbon footprint.
Hostels and educational institutions: Solar-powered hot water can be supplied to student dormitories, kitchens, and staff quarters. This is especially useful in cold areas or large campuses with shared living facilities.
Industrial applications of solar water heaters: They can be used for process heating, boiler feed water preheating, or cleaning operations in industries like textile, dairy, and food processing. It helps reduce fuel consumption and carbon footprint.

What Are the Benefits of a Solar Hot Water System?

Solar water heaters use the sun’s energy to supply hot water for domestic and commercial use. This reduces reliance on grid electricity that comes from fossil fuels. It has dual benefits: it cuts down electricity bills and reduces the carbon footprint.

Let’s check out the multiple benefits offered by solar hot water systems:

Significant energy savings: Hot water supply comes from solar energy. Hence, the utility bills are reduced.
Climate preservation: Since solar water heaters do not rely on electricity (and the types that do require electricity need it in very low amounts), they reduce the carbon footprint of the homes, housing societies, or industries that have installed them.
Low operating cost: Passive solar systems have zero running cost as they require zero electricity to function.
Long life: Once installed, solar water heaters can last for 15-20 years. And with proper maintenance, this life can be prolonged to more than 25 years.

What Are the Disadvantages of Solar Water Heaters?

One of the biggest disadvantages of solar-powered water heater systems is that they’re weather-dependent. If sunlight is scarce, they will need a backup heating element to meet the demand, which, in turn, will only increase the upfront installation cost.

Let’s check out all the major limitations of solar water geysers:

Higher investment cost compared to normal water heaters: They’re costlier than traditional geysers. However, traditional geysers consume electricity, which raises the bills. Hence, their upfront cost is worth it in relation to normal water heaters.
Performance is dependent on weather conditions: When it’s cloudy or rainy, the performance drops. At such times, there’s a need for an external heating element.
Space requirement: They need an adequate rooftop that receives abundant sunlight to function properly.
Rooftop condition matters a lot: When installing an integral collector water heater system, the rooftop needs to be in top-notch condition since these systems can weigh over 180 kgs.
No electricity generation: Unlike solar PV systems that produce electricity using sunlight, solar water heaters only heat water. They cannot produce electricity or power other appliances at home.

Conclusion

Solar water heaters are an excellent way to harness solar energy to provide hot water for domestic and commercial use. They can last for 15-20 years, and when maintained properly, their lifespan can be extended to 25+ years. Whether you need an active solar water heater or a passive one depends on the volume of hot water you need and the weather conditions in your area. Consider these factors carefully to choose the right system.
If you’re seeking alternative ways to harness solar energy and eliminate electricity bills, consider an on-grid rooftop solar system for your home, which can help you save tens of lakhs of rupees. Get in touch with SolarSquare for free. Let our experts resolve all your doubts. And there’s no pressure to book

FAQs

Q1. Does a solar water heater work in winters?

Ans. Yes. Active solar water heaters with indirect circulation are reliable in winter. They use antifreeze heat-transfer fluids and backup heating to work even in freezing temperatures. However, passive solar water geysers do not work in winters. They’re suited only for warm climates.

Q2. What is the lifespan of a solar water heater?

Ans. Most solar water heaters can last for 15-20 years. When maintained well, their life can extend to 25 years and even more.

Q3. Do solar water heaters require electricity?

Ans. Passive solar water heaters do not require electricity. The active solar-powered water heaters, on the other hand, do require electricity to power the electric pump.

Q4. What is the solar water heater price in India?

Ans. The solar water heater price in India can range from ~Rs. 19,000 to ~Rs. 1.17 lakh. This is just an estimated number based on standard market estimates. The actual price can vary significantly from manufacturer to manufacturer. The capacity and type of heater can also influence the cost.

Q5. Do solar water heaters require lithium batteries to run?

Ans. No. Solar water heaters do not require lithium batteries or any kind of battery backup. They use solar thermal energy, not electricity, to heat water. Hence, there's no need for lithium batteries.