The Low-E Baffle is a patented plastic sheet that has almost the insulating value of a Low-E glazing, but only one third of its solar energy transmission losses from reflection and absorption. Like Low-E, it is essentially free. But it can only be used in conjunction with a Low-E layer, not alone. It has been made on mass production machinery, and has passed accelerated aging tests. It was used in the Saint-Gobain sponsored Weather Panel field test in Brussels. Without the Low-E Baffle, it would impossible to capture heat from overcast skies in freezing weather, because this requires both a high insulating value and a high transmission of sunlight.
(1) e.g. U.S. patent 5,524381, see Section 30
The Weather Panel is bolted onto the steel frame from underneath. Then the water for heat storage is added, and foam insulation is inserted between the panels. A 4 x 8 foot x 5 inch (1.2 x 2.4 meter x 13 cm) Panel weights 130 pounds (60 kg), not including its Low-E, Cloud Gel, and water, which are not shown.