A solar collector is an important part of a solar water heater and uses sunlight to heat the water. Read more about the different types of solar collectors and the average prices here.


Solar collectors have different types of effi ciency depending on the system you use, whether flat plate collectors or vacuum tubes

What is a solar collector?


The  solar collectors  are devices that are designed to capture the energy generated by the sun and convert it to thermal energy. They are divided into two large groups, the low temperature collectors (used mainly in domestic heating systems) and the high temperature collectors (which are made up of mirrors and used to produce electrical energy).

The solar collectors are confused regularly with a solar panel, but they are still very different. The solar panels  generate electricity, while a solar collector uses sunlight to heat tap water.

How does a solar collector work?

The operation of a solar collector is actually very simple. The solar collector consists of metal tubes with a liquid in it. The liquid heats the liquid and then flows through a pipe system to the storage tank filled with tap water. 

After a while, the tap water in the storage tank is heated and the hot water can be used.

In addition to a solar collector, a solar water heater also consists of:

  • A storage tank in which water is stored.
  • A post-heater to provide additional heat when there is not enough solar energy available.


What is a solar collector for?

The collector takes the energy that comes from the Sun. In general, this energy is converted into heat, which is used to heat water and distribute it in homes and businesses.

Some collectors take the energy of the Sun to convert it into electricity. This can be used to turn on lights and electrical appliances,   including some solar collectors are used to light the streets and roads, in order to make them safer.

Some collectors are designed in such a way that they can store the heat produced during the day and use it during the night, which is why some people transform their houses into collectors to keep them at a warm temperature at a low cost.

Others are made in such a way that  the solar collector allows to focus the energy of the Sun at a point to create higher temperatures in a specific place or to heat fluids .

How does a solar collector work?

A solar collector captures the heat energy of the Sun and converts it into a form more easily usable by humans. Each type of solar collector works differently according to its design and the purpose for which they were created.

What should we consider to increase the efficiency of the solar collector?

As for the panels, consider:

– Orientation. In the southern hemisphere, the collectors should face north to take advantage of the sunny hours throughout the year. Variations towards the east or west are not greater than 20 degrees.

All shadows cast by other collectors, buildings, trees or terrain irregularities should be avoided.

– Inclination. The optimum inclination of the panel will ensure the maximum solar radiation at the most unfavorable time of the year: winter. 
The highest solar uptake is obtained by placing the collector perpendicular to the sun’s rays. For example: in Buenos Aires (latitude S34.5 °) the slope of the sun in winter will be 33 °. The inclination angle will be 90 ° -33 ° = 57 °.

Types of solar collectors:

Solar collectors are classified according to their purpose in:

  • Solar collectors used to collect heat

  1. No concentrators:  the collecting area (the one that intercepts the solar radiation) is the same as the one that is responsible for absorbing the heat. 
  2. Collectors with internal storage: they  have an additional thermal capacity without requiring a separate storage tank.
  3. Flat collectors and vacuum tubes:  used to heat or cool spaces and water.
  4. Air:  heat the air directly. They are used in commercial and industrial systems of heating, ventilation and air conditioning. They are classified in two categories:
  1. With glass: they  minimize the loss of heat.
  2. Without glass:  absorbent plate that passes the air through itself to separate the heat.
  1. Bowl: it  operates in a similar way to the parabolic plate, only that it has a spherical mirror with a tracking receiver.
  • Solar collectors to generate electricity

  1. Parabolic trough collectors:  generally used in solar power plants. They are composed of a parabolic reflector in the form of a channel that is used to concentrate sunlight in an insulated or heat pipe, placing a coolant in the focal point, which transfers the heat from the collectors to the boilers in the power station .
  2. Parabolic solar dish:  this is the most powerful type of collector. It consists of one or more parabolas that concentrate solar energy in a single focal point. 
  3. Power Tower:  is a large tower surrounded by mirrors, which align and concentrate sunlight on the receiver at the top of the tower, the heat is transferred to a power station below.

Before buying a solar collector, you will still have to make an important choice. There are two different types of solar collectors among which you can choose:

  • flat plate collectors
  • vacuum tube collectors

Flat plate solar collector


Flat plate solar collectors are very popular because they are simple and generally also cheap. A flat plate collector consists of a shallow container. This container closes with a transparent cover, which guarantees that the heat remains in the container correctly. 

Under the cover plate there is an absorbent, this is a black plate that is heated by absorbing sunlight. Below are the tubes with liquid in them. When the liquid is heated by the absorbent, it is used to heat the tap water in the storage tank.

Vacuum tube solar collector


This solar collector consists of different tubes made of double glazing that are side by side. 

The contents of these tubes are made under vacuum and the tubes have a special coating inside. This allows the heat to retain well. Vacuum tubes are also called heat tubes. 

The heat is collected at the top of the tubes and transferred to the solar collector. The solar collector ensures that the heat is transferred to the water.

 The vacuum tube solar collector has a higher efficiency than the flat plate solar collector. This is because the vacuum tube heats up faster and the vacuum ensures that the solar collector is particularly well insulated and does not depend on the outside temperature at all.


Solar collectors contribute to a sustainable world. The water is heated with the help of sunlight, so that less use of fossil fuels is needed. As a result, a solar collector saves on average 287 kilograms of CO2 per year. A solar collector saves the greatest amount of energy when placed at a 45 degree angle and looks south.

Save on energy costs

Of course, a solar collector is not only sustainable. You can also get many benefits with it. The amount you can save depends on the type of solar collector and the dimensions of the collector, but also on your own situation, such as water consumption and the size of your home. With a solar collector you can save on average 45% in hot water costs. If you want to calculate your annual savings, you can multiply the following factors:

  • Solar collector performance: probably between 100 and 300 m3 of gas per year.
  • The current price of gas: this is € 0.65 per m3 of gas.

By multiplying the above data with each other, you will discover what you can save annually with a solar collector. This is likely to be between € 65 and € 200. It is expected that gas prices will increase in the coming years. This is good for people with solar collectors, because the amount they save each year increases.

Solar water heater

A solar collector is part of a solar water heater. A solar water heater consists of a solar collector, a storage tank and a rear heater. A solar collector is not only available in different types, but there are also several variants of the solar water heater. 

For example, you can choose a standard solar water heater, a compact solar water heater or a central heating solar water heater. Observe in advance the various options to see what type of solar water heater best suits your needs.

 What are the advantages of solar water heaters?

On this occasion we will list the advantages of solar water heaters:

  • Reduction of expenses associated with water heating, such as electricity, gas, firewood or other fuels.
  • They can provide between 50% and 70% of the annual hot water needs, either in single-family homes or in buildings (apartments, hotels, clinics, etc.)
  • The investment is amortized quickly with the saving of electrical energy.
  • Operating and installation costs decrease as the technology develops, while fuels rise in price as they are non-renewable resources.
  • It does not emit harmful gases for health, nor gases that contribute to the greenhouse effect that affect the environment and climate change.
  • They generate a greater value to the property where they are installed.
  • Reduces dependence on external energy suppliers.

Solar collector prices

A solar collector is always installed in combination with a solar water heater. When calculating costs, you must take into account the price of the entire installation. Below is a general description of the average prices of a solar water heater and how much you can save with this.

Type of solar water heaterAvg price (incl installation)Annual savings in m3 of natural gas.Annual savings in euros
1 collector, boiler 100 liters.€ 2,200100 m3€ 65
2 collectors, boiler 100 liters.€ 3,000135 m3€ 85
2 collectors, boiler 200 liters.€ 3,500185 m3€ 120
3 collectors, boiler 300 liters.€ 5,000285 m3€ 185

As you can see, the prices depend on the contents of the boiler. The content you need depends on the size of your home and water consumption. On average about 50 liters per person can be taken into account. 

For a home with 2 people, therefore, it can mean a 100-liter solar boiler. For a solar water heater of this type, with 2 solar collectors, it will pay on average € 3,000, including installation. However, this price is not yet fixed. 

There are different ways in which you can save money on the purchase of a solar water heater. For example, always compare quotes before making a purchase. There are big differences in installer prices. When you compare prices, you can save up to 40% on your solar water heater. In a € 3 solar water heater. 000 means a substantial saving of up to € 1,200.


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