1. What is Legionella disease? 2. What are the benefits of having an installation of thermal solar panels?3. What is the payback time of the investment in a thermal solar panel?4. What is the difference between solar thermal panels and photovoltaic panels? 5. How does the thermosiphon system works? 6. How does the closed loop system works? 7. What's the difference between the thermosiphon system and closed loop system? 8. During winter, if the temperature of hot water produced by the solar panel is not enough, may I use my existing gas water heater or boiler to ensure the rest of the heating? 9. On days with little sun or in winter does the solar thermal panels work? 10. I have no equipment. The thermal solar panel is autonomous?11. How long does an installation take?12. I can only install collectors on a roof?13. What is the lifetime of thermal solar panels?14. Must it be installed in summer or winter?15. In case of shadows (eg trees) in front of the house should I install a thermal solar panel?16. What is the influence of solar thermal panels in the energy certificates?17. Are the thermal solar panels certified?18. Can I install a thermal solar system regardless of the orientation of my building?19. Can it be used in together with another equipment (gas water heater, electric water heater, boiler)? 20. The auxiliary heating system (boiler, heater or other) is required to be of natural gas or can it also be of butane gas or diesel? 21. Is the thermosyphon 300l tank equipped with a heat exchanging coil to allow the use of a wood boiler (or other) to heat water during the winter months? Does such extra coil needs to be purchased, or some sort of accessory to make this possible? 22. In case of a closed loop installation, do I also have to install an additional expansion vessel (sanitary)?23. Is it possible to place the closed loop system water tank in horizontal position?