By: Pos McMillan

I guess they have actually decreased the usage of PV generated electricity and minimized the need for batteries in off-grid system by implementing additional solar panels for direct air heating (hot-air heating system). Actually such solar heater panels can be build very cheap, especially if recycled parts are used (for example pop-cans). Detailed do-it-yourself instructions can be found here: http://solar.freeonplate.com/diy-how-to/DIY-solar-panels.htm