About the Unisol Aquecedores vacuum solar collector:

The tubes present in this vacuum-coupled solar heater are named this way precisely because the thermal insulation, which prevents the water from losing heat, is the vacuum (the best thermal insulator currently available).

Therefore, in addition to being extremely resistant to various impacts, freezing or water corrosion, the performance and effectiveness of the vacuum-coupled solar heater are far beyond the common collectors available on the market.