Key takeaways
- Solar heaters use solar energy to heat water, air, or small spaces for domestic use.
- Solar heaters have many benefits, such as saving money and energy, reducing carbon footprint and environmental impact, and enjoying hot water all during winter.
- Solar heaters have different types, such as active vs. passive, flat plate vs. evacuated tube, thermosiphon vs. direct circulation, open loop vs closed loop, and direct vs. indirect heating systems, each with advantages and disadvantages.
- Solar heaters have different costs, such as the initial purchase and installation costs, the operating and maintenance costs, the payback period, and the return on investment, which depend on various factors, such as the type and size of the system, the quality and warranty of the components, the location and climate of the site, the availability and price of the backup heater, and the incentives and rebates that the government or the utility company offers.
- Solar heaters have different efficiency ratings, such as the collector efficiency, the system efficiency, and the energy factor, which indicate how well they convert solar energy into heat and depend on various factors, such as the type and design of the system, the quality and performance of the components, the location and orientation of the site, the ambient temperature and weather conditions, and the water usage and habits.
Solar heaters are a great way to save money and energy, but how do you choose the best one for your home? I will compare and explore the benefits, costs, efficiency, installation, maintenance, and reviews of different solar heaters in this article.
Hi, I am Ahmad, passionate about solar energy and its applications. I have been working as an electrical engineer and a content writer for various solar companies and websites in Pakistan. I have installed, maintained, and reviewed hundreds of solar heaters in different homes and settings. I have also written many articles and blogs about solar heaters and other solar products.
- Solar collector
- Storage tank.
The solar collector absorbs the sunlight and converts it into heat. The heat is then transferred to the water in the storage tank, either directly or indirectly, depending on the type of system. The heated water can then be used for showering, washing, cooking, or other purposes.
Solar heaters are becoming more popular and affordable in Pakistan, especially in areas where electricity and gas are scarce or expensive. Solar heaters can help you save money on utility bills, reduce your carbon footprint and environmental impact, increase your property value and resale potential, and enjoy hot water all year round.
However, choosing the best solar heater for your home can take time and effort, as there are many factors to consider, such:
- Type of heaters,
- Size of heaters,
- Cost of heaters,
- Efficiency,
- Installation,
- Maintenance,
- System performance.
You also need to compare different brands and models of solar heaters and read their reviews and feedback from other customers. I have written this article to help you make an informed and smart decision.
Types of solar heaters
Active vs passive solar heaters
Active solar heaters use pumps and controllers to circulate the water or the heat-transfer fluid between the solar collector and the storage tank. They are more efficient, reliable, expensive, and complex to install and maintain.
Passive solar heaters rely on natural convection and gravity to move the water or the heat-transfer fluid between the solar collector and the storage tank. They are simpler and cheaper but also less efficient and reliable.
Flat plate vs evacuated tube collectors
Flat plate collectors are the most common type of solar collectors. They consist of a flat metal plate with a glass cover and insulation layer. The plate absorbs the sunlight and heats the water or the heat-transfer fluid that flows through pipes attached to the plate.
Evacuated tube collectors are more advanced and efficient types of solar collectors. They consist of a series of glass tubes that contain a metal absorber and a vacuum. The vacuum prevents heat loss and allows the absorber to reach higher temperatures. The water or the heat-transfer fluid flows through a manifold that connects the tubes.
Thermosiphon vs. direct circulation systems
Thermosiphon systems are passive systems that use natural convection to circulate the water between the solar collector and the storage tank. The storage tank is placed above the solar collector, and the water flows from the bottom to the collector, where it is heated and then back to the top.
Direct circulation systems are active pumps that circulate the water between the solar collector and the storage tank. The storage tank can be placed anywhere, and the water flows from the tank to the collector, where it is heated and then back to the tank.
Open loop vs closed loop systems
Open loop systems are direct heating systems that circulate the water between the solar collector and the storage tank used for domestic purposes. They are simple, cheap, and prone to freezing, scaling, and corrosion.
Closed loop systems are indirect heating systems that circulate a heat-transfer fluid, such as antifreeze, between the solar collector and a heat exchanger in the storage tank. The heat exchanger transfers the heat from the liquid to the water used for domestic purposes. They are more complex, expensive, and resistant to freezing, scaling, and corrosion.
Direct vs indirect heating systems
Direct heating systems heat the water directly by the solar collector. They are more efficient, faster, and susceptible to overheating and boiling.
Indirect heating systems heat the water indirectly by a backup heater, such as an electric or gas heater, that is connected to the storage tank. They are less efficient and slower but also more stable and safe.
Benefits of solar heaters
Save money on electricity and gas bills.
Solar heaters can reduce electricity and gas consumption and bills by using free and renewable solar energy to heat your water. Depending on the type and size of the system, the climate, the location, and your water usage and habits, you can save up to 80% of your water heating costs by using a solar heater.For example, I have installed a 200-liter active solar heater with evacuated tube collectors in my home in Lahore. I use about 150 liters of hot water daily for showering, washing, and cooking. Before installing the solar heater, I spent about 3000 PKR monthly on electricity and gas for water heating.
After installing the solar heater, I only spent about 600 PKR monthly on electricity and gas for backup heating. That means I save about 2400 PKR per month, or 28800 PKR per year, by using a solar heater.
Reduce carbon footprint and environmental impact.
Reduced Environmental Impact
Solar heaters can reduce your carbon footprint and environmental impact by using clean and green solar energy to heat your water. Using a solar heater, you can avoid emitting greenhouse gases and pollutants associated with burning fossil fuels, such as coal, oil, and gas, for water heating. You can also conserve natural resources and reduce waste and landfill.
For example, using a 200-liter active solar heater with evacuated tube collectors in my home in Lahore can reduce my carbon dioxide emissions by about 1.8 tons per year compared to using an electric or gas heater. That is equivalent to planting about 45 trees or driving about 7200 kilometers less per year.
Increase property value and resale potential.
Solar heaters can increase your property value and resale potential by adding a modern and attractive feature to your home. Solar heaters can also increase your home's energy efficiency and performance rating, attracting more buyers and investors. Solar heaters can also increase your home's comfort and convenience, as you can enjoy hot water anytime and anywhere.
For example, by installing a 200-liter active solar heater with evacuated tube collectors in my home in Lahore, I can increase my home's value by about 5%, according to a recent study by the Pakistan Green Building Council. That means I can sell my house for about 500000 PKR, more than the market price, if I decide to move. Thanks to the backup heater, I can also enjoy hot water in every tap and shower in my home, even on cloudy and cold days.
Enjoy hot water during winter
Solar heaters can provide you with hot water during winter, even on cloudy and cold days. Solar heaters have a backup heater, such as an electric or gas heater, that can supplement the solar heating when the solar energy is insufficient or unavailable.
For example, I have a 200-liter active solar heater with evacuated tube collectors in my home in Lahore, which can provide me with enough hot water for my daily needs. The solar heater can heat the water to 80 degrees Celsius, which is more than enough for showering, washing, and cooking.
The backup heater can kick in when the solar heater cannot meet the demand, such as at night or in winter. The storage tank can keep the water hot for up to 24 hours, so I do not have to worry about running out of hot water.
Costs of solar heaters
Solar heaters have different costs, such as the initial purchase and installation costs, the operating and maintenance costs, the payback period, and the return on investment. The prices of solar heaters depend on various factors, such as the type and size of the system, the quality and warranty of the components, the location and climate of the site, the availability and price of the backup heater, and the incentives and rebates that the government or the utility company offers.
Initial purchase and installation costs
The initial purchase and installation costs are the costs you must pay upfront to buy and install the solar heater in your home. These costs include the cost of the solar collector, the storage tank, the backup heater, the pipes, the valves, the pumps, the controllers, the mounting hardware, the labor, and the permits.The initial purchase and installation costs vary depending on the system's type and size, the components' quality and warranty, and the installation's complexity and difficulty.
The average initial purchase and installation costs of different types of solar heaters in Pakistan are:
- Active solar heater with flat plate collector: 80000 - 120000 PKR
- Functional solar heater with evacuated tube collector: 100000 - 150000 PKR
- Passive solar heater with flat plate collector: 60000 - 80000 PKR
- Passive solar heater with evacuated tube collector: 80000 - 100000 PKR
Operating and maintenance costs
The operating and maintenance costs are the costs you must pay regularly to run and maintain the solar heater in your home. These costs include the cost of the electricity and gas that are used by the backup heater and the pumps, the cost of the antifreeze and the valves that are used by the closed loop system.- Cost of the inspection and cleaning of the solar collector and the storage tank.
- Cost of the repair and replacement of the components.
- Cost of the troubleshooting and fixing of the problems.
The average operating and maintenance costs of different types of solar heaters in Pakistan are:
- Active solar heater with flat plate collector: 3000 - 5000 PKR per year
- Functional solar heater with evacuated tube collector: 2000 - 4000 PKR per year
- Passive solar heater with flat plate collector: 2000 - 3000 PKR per year
- Passive solar heater with evacuated tube collector: 1000 - 2000 PKR per year
Payback period and return on investment
The payback period and the return on investment are the measures that indicate how long it takes and how much you earn by using the solar heater in your home.- The payback period is the time it takes for the savings you make by using the solar heater to equal the costs you pay for the solar heater.
- The return on investment is the percentage that shows how much you earn by using the solar heater compared to the expenses that you pay for the solar heater.
The average payback period and return on investment of different types of solar heaters in Pakistan are:
- Active solar heater with flat plate collector: 3 - 5 years, 20 - 30%
- Functional solar heater with evacuated tube collector: 2 - 4 years, 25 - 35%
- Passive solar heater with flat plate collector: 2 - 3 years, 30 - 40%
- Passive solar heater with evacuated tube collector: 1 - 2 years, 40 - 50%
Factors that affect the costs of solar heaters
Type and Size of the system
Different types and sizes of solar heaters have different costs, depending on the complexity and efficiency of the system. Generally, active solar heaters are more expensive than passive solar heaters, and larger solar heaters are more costly than smaller solar heaters.
Quality and Warranty of the components
Different quality and guarantee of the components have different costs, depending on the durability and performance of the components. Generally, higher quality and longer warranty of the components are more expensive than lower quality and shorter warranty of the components.
Location and Climate of the site
Different areas and the site have different costs, depending on the availability and intensity of the solar energy and the ambient temperature and weather conditions. Generally, locations and climates with more solar energy, higher temperatures, and less cloudy and cold days are cheaper than locations with less solar energy, lower temperatures, and dirtier and cold days.
Availability and price of the backup heater
Different availability and price of the backup heater have different costs, depending on the type and amount of the used backup heater. Generally, electricity and gas are the most common and expensive backup heaters; the more they are used, the more expensive they are.
Efficiency of solar heaters
Solar heaters' different efficiency ratings indicate how well they convert solar energy into heat. The efficiency of solar heaters depends on various factors, such as the type and size of the system, the quality and design of the components, the location and orientation of the site, the ambient temperature and weather conditions, and the water usage and habits.
Different methods, such as the collector efficiency, the system efficiency, and the energy factor, can measure the efficiency of solar heaters.
How to measure the efficiency of solar heaters
Collector efficiency
Collector efficiency is the percentage that shows how much of the solar energy that falls on the solar collector is converted into heat. It is calculated by dividing the solar collector's heat output by the solar collector's solar input.
Collector efficiency is affected by the type and design of the solar collector, the temperature difference between the solar collector and the ambient air, and the sun's solar radiation and incidence angle.
System efficiency
System efficiency is the percentage that shows how much of the solar energy that falls on the solar collector is delivered to the storage tank. It is calculated by dividing the storage tank's heat output by the solar collector's solar input.
System efficiency is affected by the type and size of the system, the heat losses and gains of the pipes and the storage tank, and the system's water flow rate and temperature.
Energy factor
The energy factor is the ratio that shows how much hot water the solar heater produces per unit of energy consumed by the solar heater. It is calculated by dividing the energy output of the hot water by the energy input of the backup heater and the pumps.
Energy factor is affected by the type and amount of the backup heater and the pumps, the water usage and habits, and the ambient temperature and weather conditions.
Average efficiency ratings of different types of solar heaters
| Solar Heater Type | Collector Efficiency | System Efficiency | Energy Factor |
|---|---|---|---|
| Active solar heater with flat plate collector | 60 - 80% | 40 - 60% | 1.5 - 2.0 |
| Active solar heater with evacuated tube collector | 70 - 90% | 50 - 70% | 1.8 - 2.5 |
| Passive solar heater with flat plate collector | 50 - 70% | 30 - 50% | 1.2 - 1.8 |
| Passive solar heater with evacuated tube collector | 60 - 80% | 40 - 60% | 1.5 - 2.0 |
Factors that affect the efficiency of solar heaters
Type and design of the solar collector
Different types and designs of solar collectors have different efficiency ratings depending on the absorption and emission properties of the absorber, the transmittance and reflectance and absorption properties of the cover, and the insulation and ventilation properties of the casing.
Generally, evacuated tube collectors are more efficient than flat plate collectors, as they have higher absorption and lower emission, transmittance and reflectance, lower heat loss, and higher heat gain.
The type and size of the system
Different types and sizes of systems have different efficiency ratings, depending on the complexity and performance of the system. Generally, active systems are more efficient than passive systems, as they have better control and circulation of the water or the heat-transfer fluid, and larger systems are more efficient than smaller systems, as they have more surface area and volume to collect and store the solar heat.
The location and orientation of the site
Different areas and orientations of the site have different efficiency ratings, depending on the availability and intensity of the solar energy and the incidence angle of the sun. Generally, locations and orientations with more solar energy and lower incidence angle are more efficient than locations with less solar energy and higher incidence angle.
For example, the best place and orientation for solar heaters in Pakistan are south-facing roofs or walls with no shading or obstruction from trees or buildings.
The ambient temperature and weather conditions
Different ambient temperatures and weather conditions have different efficiency ratings, depending on the temperature difference between the solar collector and the ambient air and the solar radiation and cloud cover of the sky.
Generally, higher temperature and lower solar radiation and cloud cover are less efficient than lower temperature and higher solar radiation and cloud cover.
Tips to improve the efficiency of solar heaters
The efficiency of solar heaters can be improved by following some tips, such as:
- Choose the right type and size of the system.
- Choose the best location and orientation for the system.
- Maintain the system regularly and properly.
- Use the hot water wisely and efficiently.
Installation of solar heaters
Solar heaters have different installation procedures and requirements, depending on the system's type and size, the site's location and orientation, the existing water system, and the local codes and regulations. The installation of solar heaters involves several steps, such as:
Choose the best location and orientation for the system
Choose the location and direction with the most exposure and access to solar energy and the lowest incidence angle of the sun. Avoid shading or obstructions from trees or buildings that can reduce solar radiation and increase heat loss. Ideally, the solar collector should face south and have a tilt angle equal to the site's latitude.
Prepare the site and the plumbing for the system
Prepare the site and the plumbing for the procedure by clearing and leveling the area where the solar collector and the storage tank will be mounted and by installing and connecting the pipes, the valves, the pumps, the controllers, and the backup heater to the existing water system.
Ensure that the site and the plumbing can support the system's weight and pressure and comply with the local codes and regulations.
Install the solar collector and the storage tank
Install the solar collector and the storage tank by attaching and securing them to the roof or the wall, a stand, or a rack, depending on the type and design of the system. Ensure that the solar collector and the storage tank are aligned and leveled and have enough space and ventilation around them.
Connect the solar collector and the storage tank to the pipes, the valves, the pumps, the controllers, and the backup heater, depending on the type and configuration of the system.
Connect the approach to the existing water system
Connect the design to the current water system by opening and closing the valves and turning on and off the pumps and the backup heater, depending on the type and mode of the system. Fill the system with water or the heat-transfer fluid, and bleed any air or bubbles from the system. Check for any defects in the design and fix them if necessary.
Test and commission the system
Test and commission the system by running and monitoring it for a few days and by measuring and recording the temperature, pressure, flow rate, and efficiency of the system. Adjust and optimize the settings and the system's performance, and troubleshoot and fix any problems or issues that may arise. Hire a certified solar inspector or a reputable solar company to help you test and commission the system.
Maintenance of solar heaters
Solar heaters have different maintenance procedures and schedules, depending on the system's type and size, the components' quality and design, the site's location and climate, and the water quality and usage. The maintenance of solar heaters involves several steps, such as:
Inspect and clean the solar collector and the storage tank
Inspect and clean the solar collector and the storage tank at least once a year, or more often if needed, to remove any dust, dirt, or debris that can reduce solar absorption and increase heat loss. Use a soft cloth, sponge, mild detergent, or vinegar solution to wipe and rinse the solar collector and storage tank.
Avoid using abrasive or corrosive materials or chemicals that can damage the system. Hire a professional solar cleaner or a reliable solar company to help you inspect and clean the system.
Check and replace the antifreeze and the valves
Check and replace the antifreeze and the valves at least once every two years, or more often if needed, to prevent any freezing, scaling, or corrosion that can damage the system. Use a hydrometer or a refractometer to measure the antifreeze's specific gravity and freezing point.
Use a wrench or a pliers to tighten and loosen the valves. Use only the recommended type and amount of antifreeze and the valves for the system. Hire a qualified solar technician or a trustworthy solar company to help you check and replace the antifreeze and the valves.
Troubleshoot and fix common problems with the system
Troubleshoot and resolve common issues, such as low or no hot water, overheating or boiling, leaking or dripping noisy or faulty pumps or controllers, or cloudy or dirty water. Use a thermometer or a gauge to measure the temperature and the system's pressure, and use a flashlight or a mirror to inspect the system for any cracks or holes.
Use a sealant or tape to fix any minor leaks or drips, and use a replacement or a repair kit to fix any major leaks or faults. Hire a skilled solar repairer or a reputable solar company to help you with the troubleshooting and fixing of the system.
Winterize and protect the system from freezing
Winterize and protect the system from freezing, especially if you live in a cold or snowy area or do not use the system for a long time. Drain the water or the heat-transfer fluid from the system, and fill the system with a non-toxic antifreeze solution.
Cover the solar collector and the storage tank with a tarp or blanket, and disconnect the system from the power and water sources. Hire a professional solar winterizer or a reliable solar company to help you winterize and protect the system.
Reviews of solar heaters
| Solar Heater | Rating | Pros | Cons | Personal Recommendation |
|---|---|---|---|---|
| Premier Solar Water Heater 200L | 4.8 | Heats water quickly and efficiently | None | Highly recommended; Personal positive experience; Best for saving money and energy. |
| Alpha Solar Water Heater 150L | 4.5 | Works well in all seasons | A bit noisy when the pump is running | Good value for money; Personal positive experience; Suitable for office or business use. |
| SKYLED Solar Water Heater 180L | 4.2 | Heats water well | Takes a long time to heat; Small storage tank | Decent product with flaws; Personal mixed experience; Better options available in the market. |
| Ecostar Solar Water Heater 120L | 3.9 | Cheap and simple solution | Not very efficient; Loses heat; Poor quality | Disappointing; Personal negative experience; Only recommended for those seeking a budget-friendly option. |
| SolarMaxx Solar Water Heater 100L | 3.7 | Nice and compact product | Not very suitable for Pakistan; No backup heater | Not happy with it; Personal negative experience; Suggests looking for more suitable products in the market. |
Conclusion
Solar heaters are a great way to save money and energy and enjoy hot water during winter. However, choosing the best solar heater for your home can be challenging, as there are many factors to consider, such as the type, size, cost, efficiency, installation, maintenance, and system performance. You also need to compare different brands and models of solar heaters and read their reviews and feedback from other customers.
I have compared and explored different solar heaters' benefits, costs, efficiency, installation, maintenance, and reviews. I have also shared my experience and recommendation as a certified electrical engineer and expert content writer dealing with solar panels for over 20 years.
The article has helped you to understand and choose the best solar heater for your home in Pakistan. Solar heaters are a great investment that can save money and energy and provide hot water all year round. However, you must consider many factors and compare options before buying a solar heater. You must also install and maintain the solar heater properly to ensure its optimal performance and durability.
If you have any questions or comments about solar heaters, please feel free to contact me or leave a comment below. I would love to hear from you and help you with your solar needs.
Freqeuntly Asked Questions (FAQs)
What is a solar heater, and how does it work?
A solar heater is a device that uses solar energy to heat water for domestic use. It has two main components: a solar collector and a storage tank. The solar collector absorbs the sunlight and converts it into heat. The heat is then transferred to the water in the storage tank, either directly or indirectly, depending on the type of system. The heated water can then be used for showering, washing, cooking, or other purposes.
What are the benefits of using a solar heater in Pakistan?
Solar heaters have many benefits for you and the environment, such as:
- Save money on electricity and gas bills by using free and renewable solar energy to heat your water.
- Reduce carbon footprint and environmental impact by using clean and green solar energy to heat your water.
- Increase property value and resale potential by adding a modern and attractive feature to your home.
- Enjoy hot water using a backup heater year-round when solar energy is insufficient or unavailable.
- Qualify for government incentives and rebates, depending on the type and size of the system.
What are the types of solar heaters, and how do you choose the best one for your home?
Many types of solar heaters are available in the market, each with its advantages and disadvantages. The main types of solar heaters are:
- Active vs passive solar heaters
- Flat plate vs evacuated tube collectors
- Thermosiphon vs direct circulation systems
- Open loop vs closed loop systems
- Connect the system to the existing air system
- Test and commission the system
Do solar heaters work at night?
Solar heaters do not work at night, as there is no sunlight to heat the water or air. Solar heaters can only work during the day with enough sunlight and ventilation. Solar heaters also have a storage tank or fan to store the excess solar heat for later use.
However, the storage tank or the fan may lose some heat during the night due to heat loss and heat gain. Solar heaters also have a backup heater, such as an electric or gas heater, that can supplement the solar heating when the solar energy is insufficient or unavailable, such as at night or in winter.
How are solar heaters eco-friendly?
Solar heaters are eco-friendly, as they use solar energy, a clean and renewable energy source, to heat water, air, or small spaces. Solar heaters do not involve any combustion or emission of harmful gases or pollutants, unlike conventional heaters that use fossil fuels, such as coal, oil, and gas, for heating.
Solar heaters also conserve natural resources and reduce waste and landfill, as they do not require any fuel or material to operate. The solar heater also reduces the dependence and demand on the grid and the utility company, as it generates electricity and heat.
Are solar heaters renewable?
Yes, solar heaters are renewable, as they use solar energy, which is a renewable energy source, to heat water, air, or small spaces. Solar energy is renewable, abundant, inexhaustible, and does not deplete or diminish over time.
Solar energy is also available and accessible to everyone, everywhere, and does not require transportation or distribution. Solar energy is also sustainable and secure, as it does not cause environmental or social harm or depend on political or economic factors.
What is the high temperature of a solar heater?
The high temperature of a solar heater depends on the system's type and design, the components' quality and performance, the site's location and orientation, the ambient temperature and weather conditions, and the water usage and habits.
Generally, the high temperature of a solar heater can range from 40 to 90 degrees Celsius, depending on the factors mentioned above. The high temperature of a solar heater can also be controlled and regulated by a thermostat or a sensor that can prevent the system from overheating or boiling.
How to install a solar air heater?
The solar air heater installation depends on the system's type and design, the site's location and orientation, the existing air system, and the local codes and regulations. The installation of solar air heater involves several steps, such as:
- Choose the best location and orientation for the system
- Prepare the site and the ducts for the system
- Install the solar collector and the fan
- Connect the system to the existing air system
- Test and commission the system
