I advise everyone to SolarBox. I use it to heat a private house. It was possible to hang on the sunny side. First bought one, then another. The effect is clearly positive. It is difficult to measure in some units, but in spring and autumn my gas boiler is turned on only in the evening. If it is a sunny day, then the heating day is not included at all. the temperature from the collector reached 45 degrees.
Ludmila
067-569-64-00