How Many Litres Of Water Does Solar Hot Water System Heat?

The most important question that people tend to ask before they invest in a solar water heating system is: how many litres of water does a hot water system heat? 

The answer is not simple because the output of a hot water heating system depends on multiple factors, such as:

  • The size of the storage unit.
  • The area of the flat plate compressors.
  • The need of a household.
  • The size of the hot water heating system.
  • The duration and intensity of the sun.


A typical heating water system can be expected to heat around 50 litres of water at a temperature of 30C to 40C. System capacities that are defined by LPD, usually determine and correctly answer the question of how many litres of water does a solar hot water system heat. 


This means that a 100 LPD system on a good sunny day will be able to heat around 100 litres of water at 60C per day. 

Solar Hot water system in Orlando

Solar panels are an easy and cost-effective way for you to generate green energy in your homes. The solar panel has to be one of the best inventions of the last few decades and is being utilized by a large number of homes. 


With the advancements in this field, your home can become an energy saving, environmentally safe residence with a water heating system to save you a lot of money in the long run. Investing in this futuristic, safe, and environmentally friendly heating system will also guarantee that you won’t have to constantly spend money on expensive repairs.


Solar panels have evolved and become powerful enough to power air conditioners, fans, and water heaters. Solar water heaters are also known as solar domestic hot water systems and are a great way for you to produce hot water in your homes while lowering your spending. 


Solar water heating systems use panels to harvest energy from the sun and use it to heat the water in your home. Besides being cost-effective and environment-friendly, solar panels are also easy to install. 

Solar water heaters -- also called solar domestic hot water systems -- can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use -- sunshine -- is free. - [1]

Components of a Solar Water Heating System in Orlando

The solar water heating systems consist of a few major components like a collector, a storage tank, a heat exchanger, a controller system, and a backup heater. But before you invest in a solar hot water system, you should gather all the information you can regarding it, like know how many litres of water does a solar hot water system heat, how many panels does it take to heat water for a small home, how do these systems work, etc. 

Domestic Hot Water Solar Panel Close up in Orlando

How do Solar Water Heater Systems Work in Orlando

Solar water heating is a technology works hand in hand with conventional heating systems and uses the heat absorbed from the solar panels to pre-heat the water in the storage tank. 

Pre-heating the water with a solar hot water system can reduce the load on the conventional heater by increasing the water temperature up to a usable one. This effectively reduces the amount of energy the water heater takes, saves fuel, cuts back the cost of electricity, and prolongs the life of the water heater. 


There are various components of the hot water heating system that work together to provide you with hot water via the solar water heater. They are as follows:


  1. Collectors
    The panels of the solar hot water system are known as collectors and are installed on the roof generally facing towards the South or South-West. These panels are different from photovoltaic solar panels because they convert solar energy into heat instead of converting it into electrical energy.

    The solar energy hits the glass collector tubes which is then transferred to the absorber plate. The absorber plate is designed to capture the energy and convert it into heat. This heat is then relocated to a transfer fluid also called antifreeze and sent to small pipes. 
  2. Heat Exchanger and Storage Tank
    When the transfer fluid heats up, it moves through several pipes called heat exchangers that are located outside the storage tank. From here, the heat absorbed by the transfer fluid goes to the water in the tank, heating the water in your house to a usable temperature. 
  3. Controller System
    Controller systems direct and inhibit the flow of water in extreme temperatures. It prevents cold water from cycling through the system during winter and in case the transfer fluid hasn't received enough heat from the panels.
  4. Backup Heater
    Every solar water heating system comes with a backup heater to produce hot water in cold weather and cloudy days. It uses gas or electricity to generate hot water in such conditions and accounts for about 20% of your hot water usage throughout the year. 
  5. System Sizing
    One of the most crucial steps of investing in a hot water system is to make sure you are buying the appropriate size.
  6. Proper System Sizing
    If you buy a solar hot water heating system that is too big for your needs, you will have excess hot water and if you buy a hot water system that is too small, you will be spending extra money on a backup heater. Therefore, determining the hot water needs of your household before investing in one is necessary. 
  7. Collector Sizing and Roof Space
    Solar water heaters have a variety of different sizes. The flat plate collectors also vary in size, depending on the type of heater. The dimensions are roughly from 3 x 6 feet and 4 x 10 feet with a thickness of three inches. 

    The size of the evacuated tube collector depends on the number of tubes being used, for example, a 20 tube collector with a length of approximately 6 x 7 feet can produce hot water for a family of three. 

    To know how many litres of water does a water heater heat, and how many collectors need to be installed, you can calculate by dedicating a minimum of 20 square feet of space for two people in the home. For each additional person, you can add an extra 12 to 14 square feet of space.

    Using this formula, about 52 square feet of flat plate collectors on a south-facing roof can generate enough hot water for three people. Conserving this water and installing water-efficient fixtures can reduce the area of space for the flat plate collector. 
  8. Solar Storage Tank Sizing
    The storage tank must accommodate the number of people using the hot water in the house. Around 20 gallons of hot water is dedicated to a person every day. Three people living in a home, require at least 30 – 60 gallons of storage tank volume. 


If four people are residing in a house, then the storage tank must be big enough to store 80 gallons of water and if there are up to six people in the house, the capacity of the storage tank must be 120 gallons or above.

How Hot Does a Solar Hot Water Heater Get?

The solar water heaters can heat water up to 200 degrees on particularly sunny days. The pipes of the solar hot water system can absorb heat even when the sun isn't shining on it directly, which enables it to produce hot water on cloudy days as well.


There are controller systems installed in the solar hot water systems to control the water from getting too hot or from preventing the antifreeze from freezing in cold temperatures. 

Domestic hot water solar panel in Orlando Florida

What Size Solar Heating System Do I Need?

If you live in a single-person home or live as a couple, then a 100 LPD solar hot water heating system is enough.


For a house with four to six members, a 300 LPD system would be sufficient and for a house with more than six members, the capacity will increase. These numbers can vary according to the need and use of hot water in a household. 

How is Water Heated in a Direct Solar Water Heating System?

The solar energy absorbed by the collector plates gets converted into heat. It is then transported to antifreeze fluid in pipes that are situated around the storage tank. When the fluid heats up inside these pipes, the heat is then transferred to the storage tank and the water in it.

How Much Approximate Area is Required for Solar Heat Water System?

A typical solar water heating system requires up to 15 sq. ft. of roof space for a 100 LPD system. This value can vary with the size of the solar heating systems; for example, a 300 LPD system will require a space of about 40 to 45 sq. ft. of roof space.


If you have any further queries about solar hot water systems and how many litres of water does the system heat, feel free to contact Everything Solar. We have an excellent team of expert technicians who have in-depth knowledge about solar hot water heating systems and are equipped to handle all situations, answer all your questions, installations, and maintenances. Contact Everything Solar for more details. 

1. Solar Water Heaters.