SolarInfra Systems 18x48 Consumer Solar Air Heater Environmentally friendly - use only the infrared spectrum of the sun Self contained - simply stands in a south exposed window and produces heat and air circulation Portable - can be easily moved to other windows Natural light still passes through into the room Supplementary heating that reduces energy costs Environmentally friendly - use only the infrared spectrum of the sun Self contained - simply stands in a south exposed window and produces heat and air circulation Portable - can be easily moved to other windows Natural light still passes through into the room Supplementary heating that reduces energy costs For use behind single pane glass