When it comes to improving the energy efficiency of a home, the installation of solar panels appears as one of the main points to analyze. After all, this type of investment generates long-term savings in energy consumption. But to understand if this type of investment will be profitable for you, you first need to understand that there are solar panels with different functions. In recent years, solar thermal panels have been the main choice of the Portuguese at a private level. These are devices that allow water heating and support for central heating systems.However, this is not the only option on the market when it comes to solar panels. There are also the photovoltaic solar panels that produce electricity. In this case, there is not only action in a medium, as they act in the production of electrical energy, which can be used in lamps, appliances or even for storage and sale. While each option has its own advantages and disadvantageswhether at the level of utility or costbefore making a final decision, you must first analyze each of these solutions separately. So, in this article, get to know how solar thermal panels work, what models exist, what are their pros and cons, how much they cost and how they can be financed.Also read: How do solar panels work for home?
What are solar thermal panels and how do they work?
As the name implies, solar thermal panels are equipment capable of generating solar thermal energy. That is, these panels transform solar energy into thermal energy. In most cases, these panels are used to heat water in a home. And when well optimized, they can reduce the energy consumption related to water heating up to 70/80% In terms of functionality, the process is not extremely complex. Solar radiation falls on the glass cover of the solar panel. Subsequently, it enters the interior of the panel and the heat that is absorbed is transferred to a fluid, which is responsible for transporting the energy. When this fluid is heated, it circulates in a closed circle capable of transferring the heat to the water inside the accumulator. And in this way, it manages to heat the water through solar energy. This means that the thermal solar panels are useful for a given function that, as a rule, it is the heating of water in a house. However, it should be noted that most of these solar systems need a gas or electric energy support. And why does this happen? Why may need to get extra energy to heat the waters at certain times of the year, such as in winter. However, this fact does not invalidate the significant savings in a year of use. In addition, the installation of thermal solar panels It can be easily carried out in almost all dwellings and buildings.
What kind of solar thermal panels are there?
If you want to invest in thermal solar panels, know that there are currently two types of solar thermal heating systems: compact system (thermosiphon) and the forced circulation system. To understand which best suits your needs, you must first understand what sets them apart.
Compact system (thermosiphon)
The compact system (thermosiphon) is considered a simplest systemand recommended for small spaces, as it takes up little space. This compact system is self-regulating, has neither moving parts nor electronic controls. He works on the principle of gravity, making the hot water lighter and causing it to rise naturally to the accumulator. That is, this system works without pumps. In terms of advantages, it can be easily installed in a small space and can be consisting of one or two panels and a water tank. However, the water tank (accumulator) must be above the panel (collector). In terms of disadvantages, in winter its efficiency may be reducedsince the water circulation is slower, which can generate a lot of heat loss. In summer, this problem tends to disappear, as the heating is much faster.
forced circulation system
As for the forced circulation system, it involves the using a hydraulic group. In this case, the system consists by a bomb, which allows the solar liquid to circulate in the pipes. Compared to the compact system, the forced circulation system is a more complex system, and its installation requires greater technical care. However, this system has many advantages, as allows flow regulation, and allows the access to hot water more efficiently and quickly. It can also consist of one or two panels. Another advantage is that the tank is not placed outside. The accumulator is placed inside of the building, thus avoiding exposure to weather conditions and the reduction of its efficiency at certain times of the year. Furthermore, the tank can still be coupled to another source of hot water production. Finally, in terms of disadvantages in relation to the compact system, there is the issue of price. The forced circulation system requires a bigger investment, because in addition to its installation being more complex, involves the electrical cost related to the operation of the pump. When making a decision, you must take into account your budget, but also the available area, the thermal power you need and your aesthetic preferences.
How much do these panels cost?
The price of thermal solar panels varies according to some factors, such as the supplier, the capacity in liters, the system you want and even the complexity of the installation itself. But to get an idea of the values at stake, there are solutions on the market that start slightly below 2,000 euros. However, the values can reach the 3,500 euros or up to 4,000 euros. Higher prices, as a rule, are associated with the forced circulation system. But keep in mind that the price goes up considerably when opts for a 300 liter system, instead of a 200 liter one. The systems of 300 liters are advisable for households composed of 4 to 6 people. already those of 200 litersserve smaller households, composed of 2 or 4 people.Note: The values shown include VAT and kit assembly. 
Is there support to buy thermal solar panels?
In order to help citizens make their homes more sustainable, the Ministry of the Environment and Climate Action created the Support Program for More Sustainable Buildings. This program is aimed at owners of houses, apartments or buildings, and aims to improve energy efficiency in homes in Portugal. In terms of reimbursement, the program establishes different levels of support depending on the type of project. If the objective is to recover part of the investment in solar thermal systems, know that this program reimburses 85% of the valuer, but the maximum refund is 2,500 euros. However, you must first purchase the system, as the co-payment is paid by return. However, if you are thinking of applying for this support, be aware that since the 2nd of May, the program is closed. For now, it is not known if there will be new reinforcements or if the program is definitively closed. But if you intend to invest in thermal solar panels, at this moment, you will have to support this investment without the prospect of a co-payment.
Can I apply for financing from the bank?
Yup. There is a possibility of personal credit for the purpose of investing in renewable energies in some financial entities. But you can also choose to apply for funding through a personal credit without a specific purpose. However, keep in mind that the contractual conditions will vary depending on your choice.According to the most recent data from Banco de Portugal, in fourth quarter 2022a maximum APR that can be applied in personal credit for renewable energy purposes is 6.8%. In a personal loan without a specific purpose, the Maximum APR is 13.3%. But let’s look at an example to see the difference. Imagine that you take out a personal credit for renewable energies with the value of 3,000 euros. If the credit maturity is 36 months (3 years), and have a 3.5% TAN is APR of 6.3%your monthly installment is 88.09 euros. If you opt for a personal loan without a specific purpose, a loan of 3,000 euros with a term of 36 months, you can have a 8.5% TAN is 13% APR. What in practice would result in a monthly installment of 95.18 euros. For a brief moment, you may be thinking that the difference of 7.09 euros is not significant. But if you take into account the price to be paid at the end of your credit, this scenario changes. This is because the personal credit for renewable energies (payment of 88.09 euros), would have a cost of 3,171.24 euros (only taking into account the value of the monthly installment). On the other hand, personal credit without a specific purpose (payment of 95.18 euros), would have a cost of 3,426.48 euros. Ie, a difference of 255.24 euros.However, we remind you that when comparing proposals, you should take a good look at the commissions involved, mandatory insurance and taxes. Also, keep in mind that the contractual conditions may vary, depending on the purpose. And this implies different interest rates, but also different terms and financing amounts.
Is it currently worth investing in thermal solar panels?
It all depends on your goals and the budget you have available. If your goal is just to reduce energy consumption by heating water at home, this is a lasting solution, where you will be able to obtain a return on investment in the medium term. As a rule, this type of system does not require much care in maintenance, nor large dimensions for its installation. And these are two points in favor of this system. If you want to produce electricity to power your home or sell the excess energy produced, then you should consider photovoltaic solar panels. In terms of investment, these panels allow for a shorter recovery time and have a wider spectrum of uses. However, keep in mind that photovoltaic panels require a larger installation area (depending on the consumption in question), and may need a more regular maintenanceas it involves the replacement of batteries and other elements.Also read: Efficiency in energy and water consumption: How and why?